iobuf_unittest.cpp

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

#include <gtest/gtest.h>
#include <sys/types.h>
#include <sys/socket.h>                // socketpair
#include <errno.h>                     // errno
#include <fcntl.h>                     // O_RDONLY
#include <stdlib.h>
#include <memory>
#include <cstring>
#include <butil/files/temp_file.h>      // TempFile
#include <butil/containers/flat_map.h>
#include <butil/macros.h>
#include <butil/time.h>                 // Timer
#include <butil/fd_utility.h>           // make_non_blocking
#include <butil/iobuf.h>
#include <butil/single_iobuf.h>
#include <butil/logging.h>
#include <butil/fd_guard.h>
#include <butil/errno.h>
#include <butil/fast_rand.h>
#include "iobuf.pb.h"

namespace butil {
namespace iobuf {
extern void* (*blockmem_allocate)(size_t);
extern void (*blockmem_deallocate)(void*);
extern void reset_blockmem_allocate_and_deallocate();
extern int32_t block_shared_count(butil::IOBuf::Block const* b);
extern uint32_t block_cap(butil::IOBuf::Block const* b);
extern IOBuf::Block* get_tls_block_head();
extern int get_tls_block_count();
extern void remove_tls_block_chain();
extern IOBuf::Block* acquire_tls_block();
extern IOBuf::Block* share_tls_block();
extern void release_tls_block_chain(IOBuf::Block* b);
extern uint32_t block_cap(IOBuf::Block const* b);
extern uint32_t block_size(IOBuf::Block const* b);
extern IOBuf::Block* get_portal_next(IOBuf::Block const* b);
}
}

namespace {

const size_t BLOCK_OVERHEAD = 32; //impl dependent
const size_t DEFAULT_PAYLOAD = butil::IOBuf::DEFAULT_BLOCK_SIZE - BLOCK_OVERHEAD;

void check_tls_block() {
    ASSERT_EQ((butil::IOBuf::Block*)NULL, butil::iobuf::get_tls_block_head());
    printf("tls_block of butil::IOBuf was deleted\n");
}
const int ALLOW_UNUSED check_dummy = butil::thread_atexit(check_tls_block);

static butil::FlatSet<void*> s_set;

void* debug_block_allocate(size_t block_size) {
    void* b = operator new (block_size, std::nothrow);
    s_set.insert(b);
    return b;
}

void debug_block_deallocate(void* b) {
    if (1ul != s_set.erase(b)) {
        ASSERT_TRUE(false) << "Bad block=" << b;
    } else {
        operator delete(b);
    }
}

inline bool is_debug_allocator_enabled() {
    return (butil::iobuf::blockmem_allocate == debug_block_allocate);
}

void install_debug_allocator() {
    if (!is_debug_allocator_enabled()) {
        butil::iobuf::remove_tls_block_chain();
        s_set.init(1024);
        butil::iobuf::blockmem_allocate = debug_block_allocate;
        butil::iobuf::blockmem_deallocate = debug_block_deallocate;
        LOG(INFO) << "<Installed debug create/destroy>";
    }
}

void show_prof_and_rm(const char* bin_name, const char* filename, size_t topn) {
    char cmd[1024];
    if (topn != 0) {
        snprintf(cmd, sizeof(cmd), "if [ -e %s ] ; then CPUPROFILE_FREQUENCY=1000 ./pprof --text %s %s | head -%lu; rm -f %s; fi", filename, bin_name, filename, topn+1, filename);
    } else {
        snprintf(cmd, sizeof(cmd), "if [ -e %s ] ; then CPUPROFILE_FREQUENCY=1000 ./pprof --text %s %s; rm -f %s; fi", filename, bin_name, filename, filename);
    }
    ASSERT_EQ(0, system(cmd));
}

static void check_memory_leak() {
    if (is_debug_allocator_enabled()) {
        butil::IOBuf::Block* p = butil::iobuf::get_tls_block_head();
        size_t n = 0;
        while (p) {
            ASSERT_TRUE(s_set.seek(p)) << "Memory leak: " << p;
            p = butil::iobuf::get_portal_next(p);
            ++n;
        }
        ASSERT_EQ(n, s_set.size());
        ASSERT_EQ(n, (size_t)butil::iobuf::get_tls_block_count());
    }
}

class IOBufTest : public ::testing::Test{
protected:
    IOBufTest(){};
    virtual ~IOBufTest(){};
    virtual void SetUp() {
    };
    virtual void TearDown() {
        check_memory_leak();
    };
};

std::string to_str(const butil::IOBuf& p) {
    return p.to_string();
}

TEST_F(IOBufTest, append_zero) {
    int fds[2];
    ASSERT_EQ(0, pipe(fds));
    butil::IOPortal p;
    ASSERT_EQ(0, p.append_from_file_descriptor(fds[0], 0));
    ASSERT_EQ(0, close(fds[0]));
    ASSERT_EQ(0, close(fds[1]));
}

TEST_F(IOBufTest, pop_front) {
    install_debug_allocator();

    butil::IOBuf buf;
    ASSERT_EQ(0UL, buf.pop_front(1));   // nothing happened

    std::string s = "hello";
    buf.append(s);
    ASSERT_EQ(s, to_str(buf));
    ASSERT_EQ(0UL, buf.pop_front(0));   // nothing happened
    ASSERT_EQ(s, to_str(buf));

    ASSERT_EQ(1UL, buf.pop_front(1));
    s.erase(0, 1);
    ASSERT_EQ(s, to_str(buf));
    ASSERT_EQ(s.length(), buf.length());
    ASSERT_FALSE(buf.empty());

    ASSERT_EQ(s.length(), buf.pop_front(INT_MAX));
    s.clear();
    ASSERT_EQ(s, to_str(buf));
    ASSERT_EQ(0UL, buf.length());
    ASSERT_TRUE(buf.empty());

    for (size_t i = 0; i < DEFAULT_PAYLOAD * 3/2; ++i) {
        s.push_back(i);
    }
    buf.append(s);
    ASSERT_EQ(1UL, buf.pop_front(1));
    s.erase(0, 1);
    ASSERT_EQ(s, to_str(buf));
    ASSERT_EQ(s.length(), buf.length());
    ASSERT_FALSE(buf.empty());

    ASSERT_EQ(s.length(), buf.pop_front(INT_MAX));
    s.clear();
    ASSERT_EQ(s, to_str(buf));
    ASSERT_EQ(0UL, buf.length());
    ASSERT_TRUE(buf.empty());
}

TEST_F(IOBufTest, pop_back) {
    install_debug_allocator();

    butil::IOBuf buf;
    ASSERT_EQ(0UL, buf.pop_back(1));   // nothing happened

    std::string s = "hello";
    buf.append(s);
    ASSERT_EQ(s, to_str(buf));
    ASSERT_EQ(0UL, buf.pop_back(0));   // nothing happened
    ASSERT_EQ(s, to_str(buf));

    ASSERT_EQ(1UL, buf.pop_back(1));
    s.resize(s.size() - 1);
    ASSERT_EQ(s, to_str(buf));
    ASSERT_EQ(s.length(), buf.length());
    ASSERT_FALSE(buf.empty());

    ASSERT_EQ(s.length(), buf.pop_back(INT_MAX));
    s.clear();
    ASSERT_EQ(s, to_str(buf));
    ASSERT_EQ(0UL, buf.length());
    ASSERT_TRUE(buf.empty());

    for (size_t i = 0; i < DEFAULT_PAYLOAD * 3/2; ++i) {
        s.push_back(i);
    }
    buf.append(s);
    ASSERT_EQ(1UL, buf.pop_back(1));
    s.resize(s.size() - 1);
    ASSERT_EQ(s, to_str(buf));
    ASSERT_EQ(s.length(), buf.length());
    ASSERT_FALSE(buf.empty());

    ASSERT_EQ(s.length(), buf.pop_back(INT_MAX));
    s.clear();
    ASSERT_EQ(s, to_str(buf));
    ASSERT_EQ(0UL, buf.length());
    ASSERT_TRUE(buf.empty());
}

TEST_F(IOBufTest, append) {
    install_debug_allocator();

    butil::IOBuf b;
    ASSERT_EQ(0UL, b.length());
    ASSERT_TRUE(b.empty());
    ASSERT_EQ(-1, b.append(NULL));
    ASSERT_EQ(0, b.append(""));
    ASSERT_EQ(0, b.append(std::string()));
    ASSERT_EQ(-1, b.append(NULL, 1));
    ASSERT_EQ(0, b.append("dummy", 0));
    ASSERT_EQ(0UL, b.length());
    ASSERT_TRUE(b.empty());
    ASSERT_EQ(0, b.append("1"));
    ASSERT_EQ(1UL, b.length());
    ASSERT_FALSE(b.empty());
    ASSERT_EQ("1", to_str(b));
    const std::string s = "22";
    ASSERT_EQ(0, b.append(s));
    ASSERT_EQ(3UL, b.length());
    ASSERT_FALSE(b.empty());
    ASSERT_EQ("122", to_str(b));
}

TEST_F(IOBufTest, appendv) {
    install_debug_allocator();

    butil::IOBuf b;
    const_iovec vec[] = { {"hello1", 6}, {" world1", 7},
                          {"hello2", 6}, {" world2", 7},
                          {"hello3", 6}, {" world3", 7},
                          {"hello4", 6}, {" world4", 7},
                          {"hello5", 6}, {" world5", 7} };
    ASSERT_EQ(0, b.appendv(vec, arraysize(vec)));
    ASSERT_EQ("hello1 world1hello2 world2hello3 world3hello4 world4hello5 world5",
              b.to_string());

    // Make some iov_len shorter to test if iov_len works.
    vec[2].iov_len = 4;  // "hello2"
    vec[5].iov_len = 3;  // " world3"
    b.clear();
    ASSERT_EQ(0, b.appendv(vec, arraysize(vec)));
    ASSERT_EQ("hello1 world1hell world2hello3 wohello4 world4hello5 world5",
              b.to_string());

    // Append some long stuff.
    const size_t full_len = DEFAULT_PAYLOAD * 9;
    char* str = (char*)malloc(full_len);
    ASSERT_TRUE(str);
    const size_t len1 = full_len / 6;
    const size_t len2 = full_len / 3;
    const size_t len3 = full_len - len1 - len2;
    ASSERT_GT(len1, (size_t)DEFAULT_PAYLOAD);
    ASSERT_GT(len2, (size_t)DEFAULT_PAYLOAD);
    ASSERT_GT(len3, (size_t)DEFAULT_PAYLOAD);
    ASSERT_EQ(full_len, len1 + len2 + len3);

    for (size_t i = 0; i < full_len; ++i) {
        str[i] = i * 7;
    }
    const_iovec vec2[] = {{str, len1},
                          {str + len1, len2},
                          {str + len1 + len2, len3}};
    b.clear();
    ASSERT_EQ(0, b.appendv(vec2, arraysize(vec2)));
    ASSERT_EQ(full_len, b.size());
    ASSERT_EQ(0, memcmp(str, b.to_string().data(), full_len));
    free(str);
}

TEST_F(IOBufTest, reserve) {
    butil::IOBuf b;
    ASSERT_EQ(butil::IOBuf::INVALID_AREA, b.reserve(0));
    const size_t NRESERVED1 = 5;
    const butil::IOBuf::Area a1 = b.reserve(NRESERVED1);
    ASSERT_TRUE(a1 != butil::IOBuf::INVALID_AREA);
    ASSERT_EQ(NRESERVED1, b.size());
    b.append("hello world");
    ASSERT_EQ(0, b.unsafe_assign(a1, "prefix")); // `x' will not be copied
    ASSERT_EQ("prefihello world", b.to_string());
    ASSERT_EQ((size_t)16, b.size());

    // pop/append sth. from back-side and assign again.
    ASSERT_EQ((size_t)5, b.pop_back(5));
    ASSERT_EQ("prefihello ", b.to_string());
    b.append("blahblahfoobar");
    ASSERT_EQ(0, b.unsafe_assign(a1, "goodorbad")); // `x' will not be copied
    ASSERT_EQ("goodohello blahblahfoobar", b.to_string());

    // append a long string and assign again.
    std::string s1(DEFAULT_PAYLOAD * 3, '\0');
    for (size_t i = 0; i < s1.size(); ++i) {
        s1[i] = i * 7;
    }
    ASSERT_EQ(DEFAULT_PAYLOAD * 3, s1.size());
    // remove everything after reserved area
    ASSERT_GE(b.size(), NRESERVED1);
    b.pop_back(b.size() - NRESERVED1);
    ASSERT_EQ(NRESERVED1, b.size());
    b.append(s1);
    ASSERT_EQ(0, b.unsafe_assign(a1, "appleblahblah"));
    ASSERT_EQ("apple" + s1, b.to_string());

    // Reserve long
    b.pop_back(b.size() - NRESERVED1);
    ASSERT_EQ(NRESERVED1, b.size());
    const size_t NRESERVED2 = DEFAULT_PAYLOAD * 3;
    const butil::IOBuf::Area a2 = b.reserve(NRESERVED2);
    ASSERT_EQ(NRESERVED1 + NRESERVED2, b.size());
    b.append(s1);
    ASSERT_EQ(NRESERVED1 + NRESERVED2 + s1.size(), b.size());
    std::string s2(NRESERVED2, 0);
    for (size_t i = 0; i < s2.size(); ++i) {
        s2[i] = i * 13;
    }
    ASSERT_EQ(NRESERVED2, s2.size());
    ASSERT_EQ(0, b.unsafe_assign(a2, s2.data()));
    ASSERT_EQ("apple" + s2 + s1, b.to_string());
    ASSERT_EQ(0, b.unsafe_assign(a1, "orangeblahblah"));
    ASSERT_EQ("orang" + s2 + s1, b.to_string());
}

#ifndef BUTIL_USE_ASAN
// ASan will detect heap-buffer-overflow error casued by FakeBlock.
struct FakeBlock {
    int nshared;
    FakeBlock() : nshared(1) {}
};

TEST_F(IOBufTest, iobuf_as_queue) {
    install_debug_allocator();

    // If INITIAL_CAP gets bigger, creating butil::IOBuf::Block are very
    // small. Since We don't access butil::IOBuf::Block::data in this case.
    // We replace butil::IOBuf::Block with FakeBlock with only nshared (in
    // the same offset)
    FakeBlock* blocks[butil::IOBuf::INITIAL_CAP+16];
    const size_t NBLOCKS = ARRAY_SIZE(blocks);
    butil::IOBuf::BlockRef r[NBLOCKS];
    const size_t LENGTH = 7UL;
    for (size_t i = 0; i < NBLOCKS; ++i) {
        ASSERT_TRUE((blocks[i] = new FakeBlock));
        r[i].offset = 1;
        r[i].length = LENGTH;
        r[i].block = (butil::IOBuf::Block*)blocks[i];
    }

    butil::IOBuf p;
    
    // Empty
    ASSERT_EQ(0UL, p._ref_num());
    ASSERT_EQ(-1, p._pop_front_ref());
    ASSERT_EQ(0UL, p.length());

    // Add one ref
    p._push_back_ref(r[0]);
    ASSERT_EQ(1UL, p._ref_num());
    ASSERT_EQ(LENGTH, p.length());
    ASSERT_EQ(r[0], p._front_ref());
    ASSERT_EQ(r[0], p._back_ref());
    ASSERT_EQ(r[0], p._ref_at(0));
    ASSERT_EQ(2, butil::iobuf::block_shared_count(r[0].block));

    // Add second ref
    p._push_back_ref(r[1]);
    ASSERT_EQ(2UL, p._ref_num());
    ASSERT_EQ(LENGTH*2, p.length());
    ASSERT_EQ(r[0], p._front_ref());
    ASSERT_EQ(r[1], p._back_ref());
    ASSERT_EQ(r[0], p._ref_at(0));
    ASSERT_EQ(r[1], p._ref_at(1));
    ASSERT_EQ(2, butil::iobuf::block_shared_count(r[1].block));

    // Pop a ref
    ASSERT_EQ(0, p._pop_front_ref());
    ASSERT_EQ(1UL, p._ref_num());
    ASSERT_EQ(LENGTH, p.length());
    
    ASSERT_EQ(r[1], p._front_ref());
    ASSERT_EQ(r[1], p._back_ref());
    ASSERT_EQ(r[1], p._ref_at(0));
    //ASSERT_EQ(1, butil::iobuf::block_shared_count(r[0].block));

    // Pop second
    ASSERT_EQ(0, p._pop_front_ref());
    ASSERT_EQ(0UL, p._ref_num());
    ASSERT_EQ(0UL, p.length());
    //ASSERT_EQ(1, r[1].block->nshared);
    
    // Add INITIAL_CAP+2 refs, r[0] and r[1] are used, don't use again
    for (size_t i = 0; i < butil::IOBuf::INITIAL_CAP+2; ++i) {
        p._push_back_ref(r[i+2]);
        ASSERT_EQ(i+1, p._ref_num());
        ASSERT_EQ(p._ref_num()*LENGTH, p.length());
        ASSERT_EQ(r[2], p._front_ref()) << i;
        ASSERT_EQ(r[i+2], p._back_ref());
        for (size_t j = 0; j <= i; j+=std::max(1UL, i/20) /*not check all*/) {
            ASSERT_EQ(r[j+2], p._ref_at(j));
        }
        ASSERT_EQ(2, butil::iobuf::block_shared_count(r[i+2].block));
    }

    // Pop them all
    const size_t saved_ref_num = p._ref_num();
    while (p._ref_num() >= 2UL) {
        const size_t last_ref_num = p._ref_num();
        ASSERT_EQ(0, p._pop_front_ref());
        ASSERT_EQ(last_ref_num, p._ref_num()+1);
        ASSERT_EQ(p._ref_num()*LENGTH, p.length());
        const size_t f = saved_ref_num - p._ref_num() + 2;
        ASSERT_EQ(r[f], p._front_ref());
        ASSERT_EQ(r[saved_ref_num+1], p._back_ref());
        for (size_t j = 0; j < p._ref_num(); j += std::max(1UL, p._ref_num()/20)) {
            ASSERT_EQ(r[j+f], p._ref_at(j));
        }
        //ASSERT_EQ(1, r[f-1].block->nshared);
    }
    
    ASSERT_EQ(1ul, p._ref_num());
    // Pop last one
    ASSERT_EQ(0, p._pop_front_ref());
    ASSERT_EQ(0UL, p._ref_num());
    ASSERT_EQ(0UL, p.length());
    //ASSERT_EQ(1, r[saved_ref_num+1].block->nshared);

    // Delete blocks
    for (size_t i = 0; i < NBLOCKS; ++i) {
        delete blocks[i];
    }
}
#endif // BUTIL_USE_ASAN

TEST_F(IOBufTest, iobuf_sanity) {
    install_debug_allocator();
        
    LOG(INFO) << "sizeof(butil::IOBuf)=" << sizeof(butil::IOBuf)
              << " sizeof(IOPortal)=" << sizeof(butil::IOPortal);
    
    butil::IOBuf b1;
    std::string s1 = "hello world";
    const char c1 = 'A';
    const std::string s2 = "too simple";
    std::string s1c = s1;
    s1c.erase(0, 1);

    // Append a c-std::string
    ASSERT_EQ(0, b1.append(s1.c_str()));
    ASSERT_EQ(s1.length(), b1.length());
    ASSERT_EQ(s1, to_str(b1));
    ASSERT_EQ(1UL, b1._ref_num());

    // Append a char
    ASSERT_EQ(0, b1.push_back(c1));
    ASSERT_EQ(s1.length() + 1, b1.length());
    ASSERT_EQ(s1+c1, to_str(b1));
    ASSERT_EQ(1UL, b1._ref_num());
    
    // Append a std::string
    ASSERT_EQ(0, b1.append(s2));
    ASSERT_EQ(s1.length() + 1 + s2.length(), b1.length());
    ASSERT_EQ(s1+c1+s2, to_str(b1));
    ASSERT_EQ(1UL, b1._ref_num());

    // Pop first char
    ASSERT_EQ(1UL, b1.pop_front(1));
    ASSERT_EQ(1UL, b1._ref_num());
    ASSERT_EQ(s1.length() + s2.length(), b1.length());
    ASSERT_EQ(s1c+c1+s2, to_str(b1));

    // Pop all
    ASSERT_EQ(0UL, b1.pop_front(0));
    ASSERT_EQ(s1.length() + s2.length(), b1.pop_front(b1.length()+1));
    ASSERT_TRUE(b1.empty());
    ASSERT_EQ(0UL, b1.length());
    ASSERT_EQ(0UL, b1._ref_num());
    ASSERT_EQ("", to_str(b1));

    // Restore
    ASSERT_EQ(0, b1.append(s1.c_str()));
    ASSERT_EQ(0, b1.push_back(c1));
    ASSERT_EQ(0, b1.append(s2));
    
    // Cut first char
    butil::IOBuf p;
    b1.cutn(&p, 0);
    b1.cutn(&p, 1);
    ASSERT_EQ(s1.substr(0, 1), to_str(p));
    ASSERT_EQ(s1c+c1+s2, to_str(b1));

    // Cut another two and append to p
    b1.cutn(&p, 2);
    ASSERT_EQ(s1.substr(0, 3), to_str(p));
    std::string s1d = s1;
    s1d.erase(0, 3);
    ASSERT_EQ(s1d+c1+s2, to_str(b1));

    // Clear
    b1.clear();
    ASSERT_TRUE(b1.empty());
    ASSERT_EQ(0UL, b1.length());
    ASSERT_EQ(0UL, b1._ref_num());
    ASSERT_EQ("", to_str(b1));
    ASSERT_EQ(s1.substr(0, 3), to_str(p));    
}

TEST_F(IOBufTest, copy_and_assign) {
    install_debug_allocator();

    const size_t TARGET_SIZE = butil::IOBuf::DEFAULT_BLOCK_SIZE * 2;
    butil::IOBuf buf0;
    buf0.append("hello");
    ASSERT_EQ(1u, buf0._ref_num());

    // Copy-construct from SmallView
    butil::IOBuf buf1 = buf0;
    ASSERT_EQ(1u, buf1._ref_num());
    ASSERT_EQ(buf0, buf1);

    buf1.resize(TARGET_SIZE, 'z');
    ASSERT_LT(2u, buf1._ref_num());
    ASSERT_EQ(TARGET_SIZE, buf1.size());

    // Copy-construct from BigView 
    butil::IOBuf buf2 = buf1;
    ASSERT_EQ(buf1, buf2);

    // assign BigView to SmallView
    butil::IOBuf buf3;
    buf3 = buf1;
    ASSERT_EQ(buf1, buf3);

    // assign BigView to BigView
    butil::IOBuf buf4;
    buf4.resize(TARGET_SIZE, 'w');
    ASSERT_NE(buf1, buf4);
    buf4 = buf1;
    ASSERT_EQ(buf1, buf4);
}

TEST_F(IOBufTest, compare) {
    install_debug_allocator();

    const char* SEED = "abcdefghijklmnqopqrstuvwxyz";
    butil::IOBuf seedbuf;
    seedbuf.append(SEED);
    const int REP = 100;
    butil::IOBuf b1;
    for (int i = 0; i < REP; ++i) {
        b1.append(seedbuf);
        b1.append(SEED);
    }
    butil::IOBuf b2;
    for (int i = 0; i < REP * 2; ++i) {
        b2.append(SEED);
    }
    ASSERT_EQ(b1, b2);

    butil::IOBuf b3 = b2;

    b2.push_back('0');
    ASSERT_NE(b1, b2);
    ASSERT_EQ(b1, b3);
    
    b1.clear();
    b2.clear();
    ASSERT_EQ(b1, b2);
}

TEST_F(IOBufTest, append_and_cut_it_all) {
    butil::IOBuf b;
    const size_t N = 32768UL;
    for (size_t i = 0; i < N; ++i) {
        ASSERT_EQ(0, b.push_back(i));
    }
    ASSERT_EQ(N, b.length());
    butil::IOBuf p;
    b.cutn(&p, N);
    ASSERT_TRUE(b.empty());
    ASSERT_EQ(N, p.length());
}

TEST_F(IOBufTest, copy_to) {
    butil::IOBuf b;
    const std::string seed = "abcdefghijklmnopqrstuvwxyz";
    std::string src;
    for (size_t i = 0; i < 1000; ++i) {
        src.append(seed);
    }
    b.append(src);
    ASSERT_GT(b.size(), DEFAULT_PAYLOAD);
    std::string s1;
    ASSERT_EQ(src.size(), b.copy_to(&s1));
    ASSERT_EQ(src, s1);

    std::string s2;
    ASSERT_EQ(32u, b.copy_to(&s2, 32));
    ASSERT_EQ(src.substr(0, 32), s2);

    std::string s3;
    const std::string expected = src.substr(DEFAULT_PAYLOAD - 1, 33);
    ASSERT_EQ(33u, b.copy_to(&s3, 33, DEFAULT_PAYLOAD - 1));
    ASSERT_EQ(expected, s3);

    ASSERT_EQ(33u, b.append_to(&s3, 33, DEFAULT_PAYLOAD - 1));
    ASSERT_EQ(expected + expected, s3);

    butil::IOBuf b1;
    ASSERT_EQ(src.size(), b.append_to(&b1));
    ASSERT_EQ(src, b1.to_string());

    butil::IOBuf b2;
    ASSERT_EQ(32u, b.append_to(&b2, 32));
    ASSERT_EQ(src.substr(0, 32), b2.to_string());

    butil::IOBuf b3;
    ASSERT_EQ(33u, b.append_to(&b3, 33, DEFAULT_PAYLOAD - 1));
    ASSERT_EQ(expected, b3.to_string());

    ASSERT_EQ(33u, b.append_to(&b3, 33, DEFAULT_PAYLOAD - 1));
    ASSERT_EQ(expected + expected, b3.to_string());
}

TEST_F(IOBufTest, cut_by_single_text_delim) {
    install_debug_allocator();
    
    butil::IOBuf b;
    butil::IOBuf p;
    std::vector<butil::IOBuf> ps;
    std::string s1 = "1234567\n12\n\n2567";
    ASSERT_EQ(0, b.append(s1));
    ASSERT_EQ(s1.length(), b.length());
    
    for (; b.cut_until(&p, "\n") == 0; ) {
        ps.push_back(p);
        p.clear();
    }
    
    ASSERT_EQ(3UL, ps.size());
    ASSERT_EQ("1234567", to_str(ps[0]));
    ASSERT_EQ("12", to_str(ps[1]));
    ASSERT_EQ("", to_str(ps[2]));
    ASSERT_EQ("2567", to_str(b));

    b.append("\n");
    ASSERT_EQ(0, b.cut_until(&p, "\n"));
    ASSERT_EQ("2567", to_str(p));
    ASSERT_EQ("", to_str(b));
}

TEST_F(IOBufTest, cut_by_multiple_text_delim) {
    install_debug_allocator();
    
    butil::IOBuf b;
    butil::IOBuf p;
    std::vector<butil::IOBuf> ps;
    std::string s1 = "\r\n1234567\r\n12\r\n\n\r2567";
    ASSERT_EQ(0, b.append(s1));
    ASSERT_EQ(s1.length(), b.length());
    
    for (; b.cut_until(&p, "\r\n") == 0; ) {
        ps.push_back(p);
        p.clear();
    }
    
    ASSERT_EQ(3UL, ps.size());
    ASSERT_EQ("", to_str(ps[0]));
    ASSERT_EQ("1234567", to_str(ps[1]));
    ASSERT_EQ("12", to_str(ps[2]));
    ASSERT_EQ("\n\r2567", to_str(b));

    b.append("\r\n");
    ASSERT_EQ(0, b.cut_until(&p, "\r\n"));
    ASSERT_EQ("\n\r2567", to_str(p));
    ASSERT_EQ("", to_str(b));
}

TEST_F(IOBufTest, append_a_lot_and_cut_them_all) {
    install_debug_allocator();
    
    butil::IOBuf b;
    butil::IOBuf p;
    std::string s1 = "12345678901234567";
    const size_t N = 10000;
    for (size_t i= 0; i < N; ++i) {
        b.append(s1);
    }
    ASSERT_EQ(N*s1.length(), b.length());

    while (b.length() >= 7) {
        b.cutn(&p, 7);
    }
    size_t remain = s1.length()*N % 7;
    ASSERT_EQ(remain, b.length());
    ASSERT_EQ(s1.substr(s1.length() - remain, remain), to_str(b));
    ASSERT_EQ(s1.length()*N/7*7, p.length());
}

TEST_F(IOBufTest, cut_into_fd_tiny) {
    install_debug_allocator();
    
    butil::IOPortal b1, b2;
    std::string ref;
    int fds[2];

    for (int j = 10; j > 0; --j) {
        ref.push_back(j);
    }
    b1.append(ref);
    ASSERT_EQ(1UL, b1.pop_front(1));
    ref.erase(0, 1);
    ASSERT_EQ(ref, to_str(b1));
    LOG(INFO) << "ref.size=" << ref.size();
    
    //ASSERT_EQ(0, pipe(fds));
    ASSERT_EQ(0, socketpair(AF_UNIX, SOCK_STREAM, 0, fds));

    butil::make_non_blocking(fds[0]);
    butil::make_non_blocking(fds[1]);
    
    while (!b1.empty() || b2.length() != ref.length()) {
        size_t b1len = b1.length(), b2len = b2.length();
        errno = 0;
        printf("b1.length=%lu - %ld (%m), ",
               b1len, b1.cut_into_file_descriptor(fds[1]));
        printf("b2.length=%lu + %ld (%m)\n",
               b2len, b2.append_from_file_descriptor(fds[0], LONG_MAX));
    }
    printf("b1.length=%lu, b2.length=%lu\n", b1.length(), b2.length());

    ASSERT_EQ(ref, to_str(b2));
    
    close(fds[0]);
    close(fds[1]);
}

TEST_F(IOBufTest, cut_multiple_into_fd_tiny) {
    install_debug_allocator();
    
    butil::IOBuf* b1[10];
    butil::IOPortal b2;
    std::string ref;
    int fds[2];

    for (size_t j = 0; j < ARRAY_SIZE(b1); ++j) {
        std::string s;
        for (int i = 10; i > 0; --i) {
            s.push_back(j * 10 + i);
        }
        ref.append(s);
        butil::IOPortal* b = new butil::IOPortal();
        b->append(s);
        b1[j] = b;
    }
    
    ASSERT_EQ(0, socketpair(AF_UNIX, SOCK_STREAM, 0, fds));
    butil::make_non_blocking(fds[0]);
    butil::make_non_blocking(fds[1]);
    
    ASSERT_EQ((ssize_t)ref.length(),
              butil::IOBuf::cut_multiple_into_file_descriptor(
                  fds[1], b1, ARRAY_SIZE(b1)));
    for (size_t j = 0; j < ARRAY_SIZE(b1); ++j) {
        ASSERT_TRUE(b1[j]->empty());
        delete (butil::IOPortal*)b1[j];
        b1[j] = NULL;
    }
    ASSERT_EQ((ssize_t)ref.length(),
              b2.append_from_file_descriptor(fds[0], LONG_MAX));
    ASSERT_EQ(ref, to_str(b2));
    
    close(fds[0]);
    close(fds[1]);
}

TEST_F(IOBufTest, cut_into_fd_a_lot_of_data) {
    install_debug_allocator();

    butil::IOPortal b0, b1, b2;
    std::string s, ref;
    int fds[2];

    for (int j = rand()%7777+300000; j > 0; --j) {
        ref.push_back(j);
        s.push_back(j);

        if (s.length() == 1024UL || j == 1) {
            b0.append(s);
            ref.append("tailing");
            b0.cutn(&b1, b0.length());
            ASSERT_EQ(0, b1.append("tailing"));
            s.clear();
        }
    }

    ASSERT_EQ(ref.length(), b1.length());
    ASSERT_EQ(ref, to_str(b1));
    ASSERT_TRUE(b0.empty());
    LOG(INFO) << "ref.size=" << ref.size();

    //ASSERT_EQ(0, pipe(fds));
    ASSERT_EQ(0, socketpair(AF_UNIX, SOCK_STREAM, 0, fds));
    butil::make_non_blocking(fds[0]);
    butil::make_non_blocking(fds[1]);
    const int sockbufsize = 16 * 1024 - 17;
    ASSERT_EQ(0, setsockopt(fds[1], SOL_SOCKET, SO_SNDBUF,
                            (const char*)&sockbufsize, sizeof(int)));
    ASSERT_EQ(0, setsockopt(fds[0], SOL_SOCKET, SO_RCVBUF,
                            (const char*)&sockbufsize, sizeof(int)));
    
    while (!b1.empty() || b2.length() != ref.length()) {
        size_t b1len = b1.length(), b2len = b2.length();
        errno = 0;
        printf("b1.length=%lu - %ld (%m), ", b1len, b1.cut_into_file_descriptor(fds[1]));
        printf("b2.length=%lu + %ld (%m)\n", b2len, b2.append_from_file_descriptor(fds[0], LONG_MAX));
    }
    printf("b1.length=%lu, b2.length=%lu\n", b1.length(), b2.length());

    ASSERT_EQ(ref, to_str(b2));
    
    close(fds[0]);
    close(fds[1]);
}

TEST_F(IOBufTest, cut_by_delim_perf) {
    butil::iobuf::reset_blockmem_allocate_and_deallocate();
    
    butil::IOBuf b;
    butil::IOBuf p;
    std::vector<butil::IOBuf> ps;
    std::string s1 = "123456789012345678901234567890\n";
    const size_t N = 100000;
    for (size_t i = 0; i < N; ++i) {
        ASSERT_EQ(0, b.append(s1));
    }
    ASSERT_EQ(N * s1.length(), b.length());

    butil::Timer t;
    //ProfilerStart("cutd.prof");
    t.start();
    for (; b.cut_until(&p, "\n") == 0; ) { }
    t.stop();
    //ProfilerStop();

    LOG(INFO) << "IOPortal::cut_by_delim takes "
              << t.n_elapsed()/N << "ns, tp="
              << s1.length() * N * 1000.0 / t.n_elapsed () << "MB/s";
    show_prof_and_rm("test_iobuf", "cutd.prof", 10);
}


TEST_F(IOBufTest, cut_perf) {
    butil::iobuf::reset_blockmem_allocate_and_deallocate();
    
    butil::IOBuf b;
    butil::IOBuf p;
    const size_t length = 60000000UL;
    const size_t REP = 10;
    butil::Timer t;
    std::string s = "1234567890";
    const bool push_char = false;

    if (!push_char) {
        //ProfilerStart("iobuf_append.prof");
        t.start();
        for (size_t j = 0; j < REP; ++j) {
            b.clear();
            for (size_t i = 0; i < length/s.length(); ++i) {
                b.append(s);
            }
        }
        t.stop();
        //ProfilerStop();
        LOG(INFO) << "IOPortal::append(std::string_" << s.length() << ") takes "
                  << t.n_elapsed() * s.length() / length / REP << "ns, tp="
                  << REP * length * 1000.0 / t.n_elapsed () << "MB/s";
    } else {
        //ProfilerStart("iobuf_pushback.prof");
        t.start();
        for (size_t i = 0; i < length; ++i) {
            b.push_back(i);
        }
        t.stop();
        //ProfilerStop();
        LOG(INFO) << "IOPortal::push_back(char) takes "
                  << t.n_elapsed() / length << "ns, tp="
                  << length * 1000.0 / t.n_elapsed () << "MB/s";
    }

    ASSERT_EQ(length, b.length());

    size_t w[3] = { 16, 128, 1024 };
    //char name[32];

    for (size_t i = 0; i < ARRAY_SIZE(w); ++i) {
        // snprintf(name, sizeof(name), "iobuf_cut%lu.prof", w[i]);
        // ProfilerStart(name);
    
        t.start ();
        while (b.length() >= w[i]+12) {
            b.cutn(&p, 12);
            b.cutn(&p, w[i]);
        }
        t.stop ();

        //ProfilerStop();
        
        LOG(INFO) << "IOPortal::cutn(12+" << w[i] << ") takes "
                  << t.n_elapsed()*(w[i]+12)/length << "ns, tp="
                  << length * 1000.0 / t.n_elapsed () << "MB/s";
    
        ASSERT_LT(b.length(), w[i]+12);

        t.start();
        b.append(p);
        t.stop();
        LOG(INFO) << "IOPortal::append(butil::IOBuf) takes "
                  << t.n_elapsed ()/p._ref_num() << "ns, tp="
                  << length * 1000.0 / t.n_elapsed () << "MB/s";
        
        p.clear();
        ASSERT_EQ(length, b.length());
    }

    show_prof_and_rm("test_iobuf", "./iobuf_append.prof", 10);
    show_prof_and_rm("test_iobuf", "./iobuf_pushback.prof", 10);
}

TEST_F(IOBufTest, append_store_append_cut) {
    butil::iobuf::reset_blockmem_allocate_and_deallocate();
    
    std::string ref;
    ref.resize(rand()%376813+19777777);
    for (size_t j = 0; j < ref.size(); ++j) {
        ref[j] = j;
    }
    
    butil::IOPortal b1, b2;
    std::vector<butil::IOBuf> ps;
    ssize_t nr;
    size_t HINT = 16*1024UL;
    butil::Timer t;
    size_t w[3] = { 16, 128, 1024 };
    char name[64];
    char profname[64];
    char cmd[512];
    bool write_to_dev_null = true;
    size_t nappend, ncut;

    butil::TempFile f;
    ASSERT_EQ(0, f.save_bin(ref.data(), ref.length()));
    
    for (size_t i = 0; i < ARRAY_SIZE(w); ++i) {
        ps.reserve(ref.size()/(w[i]+12) + 1);
        // LOG(INFO) << "ps.cap=" << ps.capacity();

        const int ifd = open(f.fname(), O_RDONLY);
        ASSERT_TRUE(ifd > 0);
        if (write_to_dev_null) {
            snprintf(name, sizeof(name), "/dev/null");
        } else {
            snprintf(name, sizeof(name), "iobuf_asac%lu.output", w[i]);
            snprintf(cmd, sizeof(cmd), "cmp %s %s", f.fname(), name);
        }
        const int ofd = open(name, O_CREAT | O_WRONLY, 0666);
        ASSERT_TRUE(ofd > 0) << strerror(errno);
        snprintf(profname, sizeof(profname), "iobuf_asac%lu.prof", w[i]);
        
        //ProfilerStart(profname);
        t.start();

        nappend = ncut = 0;
        while ((nr = b1.append_from_file_descriptor(ifd, HINT)) > 0) {
            ++nappend;
            while (b1.length() >= w[i] + 12) {
                butil::IOBuf p;
                b1.cutn(&p, 12);
                b1.cutn(&p, w[i]);
                ps.push_back(p);
            }
        }
        for (size_t j = 0; j < ps.size(); ++j) {
            b2.append(ps[j]);
            if (b2.length() >= HINT) {
                b2.cut_into_file_descriptor(ofd);
            }
        }
        b2.cut_into_file_descriptor(ofd);
        b1.cut_into_file_descriptor(ofd);

        close(ifd);
        close(ofd);
        t.stop();
        //ProfilerStop();

        ASSERT_TRUE(b1.empty());
        ASSERT_TRUE(b2.empty());
        //LOG(INFO) << "ps.size=" << ps.size();
        ps.clear();
        LOG(INFO) << "Bandwidth of append(" << f.fname() << ")->cut(12+" << w[i]
                  << ")->store->append->cut(" << name << ") is "
                  << ref.length() * 1000.0 / t.n_elapsed () << "MB/s";

        if (!write_to_dev_null) {
            ASSERT_EQ(0, system(cmd));
        }
	if (!write_to_dev_null) {
           remove(name);
	}
    }

    for (size_t i = 0; i < ARRAY_SIZE(w); ++i) {
        snprintf(name, sizeof(name), "iobuf_asac%lu.prof", w[i]);
        show_prof_and_rm("test_iobuf", name, 10);
    }
}

TEST_F(IOBufTest, conversion_with_protobuf) {
    const int REP = 1000;
    proto::Misc m1;
    m1.set_required_enum(proto::CompressTypeGzip);
    m1.set_required_uint64(0xdeadbeef);
    m1.set_optional_uint64(10000);
    m1.set_required_string("hello iobuf");
    m1.set_optional_string("hello iobuf again");
    for (int i = 0; i < REP; ++i) {
        char buf[16];
        snprintf(buf, sizeof(buf), "value%d", i);
        m1.add_repeated_string(buf);
    }
    m1.set_required_bool(true);
    m1.set_required_int32(0xbeefdead);

    butil::IOBuf buf;
    const std::string header("just-make-sure-wrapper-does-not-clear-IOBuf");
    ASSERT_EQ(0, buf.append(header));
    butil::IOBufAsZeroCopyOutputStream out_wrapper(&buf);
    ASSERT_EQ(0, out_wrapper.ByteCount());
    ASSERT_TRUE(m1.SerializeToZeroCopyStream(&out_wrapper));
    ASSERT_EQ((size_t)m1.ByteSize() + header.size(), buf.length());
    ASSERT_EQ(m1.ByteSize(), out_wrapper.ByteCount());

    ASSERT_EQ(header.size(), buf.pop_front(header.size()));
    butil::IOBufAsZeroCopyInputStream in_wrapper(buf);
    ASSERT_EQ(0, in_wrapper.ByteCount());
    {
        const void* dummy_blk = NULL;
        int dummy_size = 0;
        ASSERT_TRUE(in_wrapper.Next(&dummy_blk, &dummy_size));
        ASSERT_EQ(dummy_size, in_wrapper.ByteCount());
        in_wrapper.BackUp(1);
        ASSERT_EQ(dummy_size - 1, in_wrapper.ByteCount());
        const void* dummy_blk2 = NULL;
        int dummy_size2 = 0;
        ASSERT_TRUE(in_wrapper.Next(&dummy_blk2, &dummy_size2));
        ASSERT_EQ(1, dummy_size2);
        ASSERT_EQ((char*)dummy_blk + dummy_size - 1, (char*)dummy_blk2);
        ASSERT_EQ(dummy_size, in_wrapper.ByteCount());
        in_wrapper.BackUp(dummy_size);
        ASSERT_EQ(0, in_wrapper.ByteCount());
    }
    proto::Misc m2;
    ASSERT_TRUE(m2.ParseFromZeroCopyStream(&in_wrapper));
    ASSERT_EQ(m1.ByteSize(), in_wrapper.ByteCount());
    ASSERT_EQ(m2.ByteSize(), in_wrapper.ByteCount());
    
    ASSERT_EQ(m1.required_enum(), m2.required_enum());
    ASSERT_FALSE(m2.has_optional_enum());
    ASSERT_EQ(m1.required_uint64(), m2.required_uint64());
    ASSERT_TRUE(m2.has_optional_uint64());
    ASSERT_EQ(m1.optional_uint64(), m2.optional_uint64());
    ASSERT_EQ(m1.required_string(), m2.required_string());
    ASSERT_TRUE(m2.has_optional_string());
    ASSERT_EQ(m1.optional_string(), m2.optional_string());
    ASSERT_EQ(REP, m2.repeated_string_size());
    for (int i = 0; i < REP; ++i) {
        ASSERT_EQ(m1.repeated_string(i), m2.repeated_string(i));
    }
    ASSERT_EQ(m1.required_bool(), m2.required_bool());
    ASSERT_FALSE(m2.has_optional_bool());
    ASSERT_EQ(m1.required_int32(), m2.required_int32());
    ASSERT_FALSE(m2.has_optional_int32());
}

TEST_F(IOBufTest, extended_backup) {
    for (int i = 0; i < 2; ++i) {
        std::cout << "i=" << i << std::endl;
        // Consume the left TLS block so that cases are easier to check.
        butil::iobuf::remove_tls_block_chain();
        butil::IOBuf src;
        const int BLKSIZE = (i == 0 ? 1024 : butil::IOBuf::DEFAULT_BLOCK_SIZE);
        const int PLDSIZE = BLKSIZE - BLOCK_OVERHEAD;
        butil::IOBufAsZeroCopyOutputStream out_stream1(&src, BLKSIZE);
        butil::IOBufAsZeroCopyOutputStream out_stream2(&src);
        butil::IOBufAsZeroCopyOutputStream & out_stream =
            (i == 0 ? out_stream1 : out_stream2);
        void* blk1 = NULL;
        int size1 = 0;
        ASSERT_TRUE(out_stream.Next(&blk1, &size1));
        ASSERT_EQ(PLDSIZE, size1);
        ASSERT_EQ(size1, out_stream.ByteCount());
        void* blk2 = NULL;
        int size2 = 0;
        ASSERT_TRUE(out_stream.Next(&blk2, &size2));
        ASSERT_EQ(PLDSIZE, size2);
        ASSERT_EQ(size1 + size2, out_stream.ByteCount());
        // BackUp a size that's valid for all ZeroCopyOutputStream
        out_stream.BackUp(PLDSIZE / 2);
        ASSERT_EQ(size1 + size2 - PLDSIZE / 2, out_stream.ByteCount());
        void* blk3 = NULL;
        int size3 = 0;
        ASSERT_TRUE(out_stream.Next(&blk3, &size3));
        ASSERT_EQ((char*)blk2 + PLDSIZE / 2, blk3);
        ASSERT_EQ(PLDSIZE / 2, size3);
        ASSERT_EQ(size1 + size2, out_stream.ByteCount());

        // BackUp a size that's undefined in regular ZeroCopyOutputStream
        out_stream.BackUp(PLDSIZE * 2);
        ASSERT_EQ(0, out_stream.ByteCount());
        void* blk4 = NULL;
        int size4 = 0;
        ASSERT_TRUE(out_stream.Next(&blk4, &size4));
        ASSERT_EQ(PLDSIZE, size4);
        ASSERT_EQ(size4, out_stream.ByteCount());
        if (i == 1) {
            ASSERT_EQ(blk1, blk4);
        }
        void* blk5 = NULL;
        int size5 = 0;
        ASSERT_TRUE(out_stream.Next(&blk5, &size5));
        ASSERT_EQ(PLDSIZE, size5);
        ASSERT_EQ(size4 + size5, out_stream.ByteCount());
        if (i == 1) {
            ASSERT_EQ(blk2, blk5);
        }
    }
}

TEST_F(IOBufTest, backup_iobuf_never_called_next) {
    {
        // Consume the left TLS block so that later cases are easier
        // to check.
        butil::IOBuf dummy;
        butil::IOBufAsZeroCopyOutputStream dummy_stream(&dummy);
        void* dummy_data = NULL;
        int dummy_size = 0;
        ASSERT_TRUE(dummy_stream.Next(&dummy_data, &dummy_size));
    }
    butil::IOBuf src;
    const size_t N = DEFAULT_PAYLOAD * 2;
    src.resize(N);
    ASSERT_EQ(2u, src.backing_block_num());
    ASSERT_EQ(N, src.size());
    butil::IOBufAsZeroCopyOutputStream out_stream(&src);
    out_stream.BackUp(1); // also succeed.
    ASSERT_EQ(-1, out_stream.ByteCount());
    ASSERT_EQ(DEFAULT_PAYLOAD * 2 - 1, src.size());
    ASSERT_EQ(2u, src.backing_block_num());
    void* data0 = NULL;
    int size0 = 0;
    ASSERT_TRUE(out_stream.Next(&data0, &size0));
    ASSERT_EQ(1, size0);
    ASSERT_EQ(0, out_stream.ByteCount());
    ASSERT_EQ(2u, src.backing_block_num());
    void* data1 = NULL;
    int size1 = 0;
    ASSERT_TRUE(out_stream.Next(&data1, &size1));
    ASSERT_EQ(size1, out_stream.ByteCount());
    ASSERT_EQ(3u, src.backing_block_num());
    ASSERT_EQ(N + size1, src.size());
    void* data2 = NULL;
    int size2 = 0;    
    ASSERT_TRUE(out_stream.Next(&data2, &size2));
    ASSERT_EQ(size1 + size2, out_stream.ByteCount());
    ASSERT_EQ(4u, src.backing_block_num());
    ASSERT_EQ(N + size1 + size2, src.size());
    LOG(INFO) << "Backup1";
    out_stream.BackUp(size1); // intended size1, not size2 to make this BackUp
    // to cross boundary of blocks.
    ASSERT_EQ(size2, out_stream.ByteCount());
    ASSERT_EQ(N + size2, src.size());
    LOG(INFO) << "Backup2";
    out_stream.BackUp(size2);
    ASSERT_EQ(0, out_stream.ByteCount());
    ASSERT_EQ(N, src.size());
}

void *backup_thread(void *arg) {
    butil::IOBufAsZeroCopyOutputStream *wrapper = 
        (butil::IOBufAsZeroCopyOutputStream *)arg;
    wrapper->BackUp(1024);
    return NULL;
}

TEST_F(IOBufTest, backup_in_another_thread) {
    butil::IOBuf buf;
    butil::IOBufAsZeroCopyOutputStream wrapper(&buf);
    size_t alloc_size = 0;
    for (int i = 0; i < 10; ++i) {
        void *data; 
        int len;
        ASSERT_TRUE(wrapper.Next(&data, &len));
        alloc_size += len;
    }
    ASSERT_EQ(alloc_size, buf.length());
    for (int i = 0; i < 10; ++i) {
        void *data; 
        int len;
        ASSERT_TRUE(wrapper.Next(&data, &len));
        alloc_size += len;
        pthread_t tid;
        pthread_create(&tid, NULL, backup_thread, &wrapper);
        pthread_join(tid, NULL);
    }
    ASSERT_EQ(alloc_size - 1024 * 10, buf.length()); 
}

TEST_F(IOBufTest, own_block) {
    butil::IOBuf buf;
    const ssize_t BLOCK_SIZE = 1024;
    butil::IOBuf::Block *saved_tls_block = butil::iobuf::get_tls_block_head();
    butil::IOBufAsZeroCopyOutputStream wrapper(&buf, BLOCK_SIZE);
    int alloc_size = 0;
    for (int i = 0; i < 100; ++i) {
        void *data;
        int size;
        ASSERT_TRUE(wrapper.Next(&data, &size));
        alloc_size += size;
        if (size > 1) {
            wrapper.BackUp(1);
            alloc_size -= 1;
        }
    }
    ASSERT_EQ(static_cast<size_t>(alloc_size), buf.length());
    ASSERT_EQ(saved_tls_block, butil::iobuf::get_tls_block_head());
    ASSERT_EQ(butil::iobuf::block_cap(buf._front_ref().block), BLOCK_SIZE - BLOCK_OVERHEAD);
}

struct Foo1 {
    explicit Foo1(int x2) : x(x2) {}
    int x;
};

struct Foo2 {
    std::vector<Foo1> foo1;
};

std::ostream& operator<<(std::ostream& os, const Foo1& foo1) {
    return os << "foo1.x=" << foo1.x;
}

std::ostream& operator<<(std::ostream& os, const Foo2& foo2) {
    for (size_t i = 0; i < foo2.foo1.size(); ++i) {
        os << "foo2[" << i << "]=" << foo2.foo1[i];
    }
    return os;
}

TEST_F(IOBufTest, as_ostream) {
    butil::iobuf::reset_blockmem_allocate_and_deallocate();

    butil::IOBufBuilder builder;
    LOG(INFO) << "sizeof(IOBufBuilder)=" << sizeof(builder) << std::endl
              << "sizeof(IOBuf)=" << sizeof(butil::IOBuf) << std::endl
              << "sizeof(IOBufAsZeroCopyOutputStream)="
              << sizeof(butil::IOBufAsZeroCopyOutputStream) << std::endl
              << "sizeof(ZeroCopyStreamAsStreamBuf)="
              << sizeof(butil::ZeroCopyStreamAsStreamBuf) << std::endl
              << "sizeof(ostream)=" << sizeof(std::ostream);
    int x = -1;
    builder << 2 << " " << x << " " << 1.1 << " hello ";
    ASSERT_EQ("2 -1 1.1 hello ", builder.buf().to_string());

    builder << "world!";
    ASSERT_EQ("2 -1 1.1 hello world!", builder.buf().to_string());

    builder.buf().clear();
    builder << "world!";
    ASSERT_EQ("world!", builder.buf().to_string());

    Foo2 foo2;
    for (int i = 0; i < 10000; ++i) {
        foo2.foo1.push_back(Foo1(i));
    }
    builder.buf().clear();
    builder << "<before>" << foo2 << "<after>";
    std::ostringstream oss;
    oss << "<before>" << foo2 << "<after>";
    ASSERT_EQ(oss.str(), builder.buf().to_string());

    butil::IOBuf target;
    builder.move_to(target);
    ASSERT_TRUE(builder.buf().empty());
    ASSERT_EQ(oss.str(), target.to_string());

    std::ostringstream oss2;
    oss2 << target;
    ASSERT_EQ(oss.str(), oss2.str());
}

TEST_F(IOBufTest, append_from_fd_with_offset) {
    butil::TempFile file;
    file.save("dummy");
    butil::fd_guard fd(open(file.fname(), O_RDWR | O_TRUNC));
    ASSERT_TRUE(fd >= 0) << file.fname() << ' ' << berror();
    butil::IOPortal buf;
    char dummy[10 * 1024];
    buf.append(dummy, sizeof(dummy));
    ASSERT_EQ((ssize_t)sizeof(dummy), buf.cut_into_file_descriptor(fd));
    for (size_t i = 0; i < sizeof(dummy); ++i) {
        butil::IOPortal b0;
        ASSERT_EQ(sizeof(dummy) - i, (size_t)b0.pappend_from_file_descriptor(fd, i, sizeof(dummy))) << berror();
        char tmp[sizeof(dummy)];
        ASSERT_EQ(0, memcmp(dummy + i, b0.fetch(tmp, b0.length()), b0.length()));
    }

}

static butil::atomic<int> s_nthread(0);
static long number_per_thread = 1024;

void* cut_into_fd(void* arg) {
    int fd = (int)(long)arg;
    const long start_num = number_per_thread * 
        s_nthread.fetch_add(1, butil::memory_order_relaxed);
    off_t offset = start_num * sizeof(int);
    for (int i = 0; i < number_per_thread; ++i) {
        int to_write = start_num + i;
        butil::IOBuf out;
        out.append(&to_write, sizeof(int));
        CHECK_EQ(out.pcut_into_file_descriptor(fd, offset + sizeof(int) * i), 
                 (ssize_t)sizeof(int));
    }
    return NULL;
}

TEST_F(IOBufTest, cut_into_fd_with_offset_multithreaded) {
    s_nthread.store(0);
    number_per_thread = 10240;
    pthread_t threads[8];
    long fd = open(".out.txt", O_RDWR | O_CREAT | O_TRUNC, 0644);
    ASSERT_TRUE(fd >= 0) << berror();
    for (size_t i = 0; i < ARRAY_SIZE(threads); ++i) {
        ASSERT_EQ(0, pthread_create(&threads[i], NULL, cut_into_fd, (void*)fd));
    }
    for (size_t i = 0; i < ARRAY_SIZE(threads); ++i) {
        pthread_join(threads[i], NULL);
    }
    for (int i = 0; i < number_per_thread * (int)ARRAY_SIZE(threads); ++i) {
        off_t offset = i * sizeof(int);
        butil::IOPortal in;
        ASSERT_EQ((ssize_t)sizeof(int), in.pappend_from_file_descriptor(fd, offset, sizeof(int)));
        int j;
        ASSERT_EQ(sizeof(j), in.cutn(&j, sizeof(j)));
        ASSERT_EQ(i, j);
    }
}

TEST_F(IOBufTest, slice) {
    size_t N = 100000;
    std::string expected;
    expected.reserve(N);
    butil::IOBuf buf;
    for (size_t i = 0; i < N; ++i) {
        expected.push_back(i % 26 + 'a');
        buf.push_back(i % 26 + 'a');
    }
    const size_t block_count = buf.backing_block_num();
    std::string actual;
    actual.reserve(expected.size());
    for (size_t i = 0; i < block_count; ++i) {
        butil::StringPiece p = buf.backing_block(i);
        ASSERT_FALSE(p.empty());
        actual.append(p.data(), p.size());
    }
    ASSERT_TRUE(expected == actual);
}

TEST_F(IOBufTest, swap) {
    butil::IOBuf a;
    a.append("I'am a");
    butil::IOBuf b;
    b.append("I'am b");
    std::swap(a, b);
    ASSERT_TRUE(a.equals("I'am b"));
    ASSERT_TRUE(b.equals("I'am a"));
}

TEST_F(IOBufTest, resize) {
    butil::IOBuf a;
    a.resize(100);
    std::string as;
    as.resize(100);
    butil::IOBuf b;
    b.resize(100, 'b');
    std::string bs;
    bs.resize(100, 'b');
    ASSERT_EQ(100u, a.length());
    ASSERT_EQ(100u, b.length());
    ASSERT_TRUE(a.equals(as));
    ASSERT_TRUE(b.equals(bs));
}

TEST_F(IOBufTest, iterate_bytes) {
    butil::IOBuf a;
    a.append("hello world");
    std::string saved_a = a.to_string();
    size_t n = 0;
    butil::IOBufBytesIterator it(a);
    for (; it != NULL; ++it, ++n) {
        ASSERT_EQ(saved_a[n], *it);
    }
    ASSERT_EQ(saved_a.size(), n);
    ASSERT_TRUE(saved_a == a);

    // append more to the iobuf, iterator should still be ended.
    a.append(", this is iobuf");
    ASSERT_TRUE(it == NULL);

    // append more-than-one-block data to the iobuf
    for (int i = 0; i < 1024; ++i) {
        a.append("ab33jm4hgaklkv;2[25lj4lkj312kl4j321kl4j3k");
    }
    saved_a = a.to_string();
    n = 0;
    for (butil::IOBufBytesIterator it2(a); it2 != NULL; it2++/*intended post++*/, ++n) {
        ASSERT_EQ(saved_a[n], *it2);
    }
    ASSERT_EQ(saved_a.size(), n);
    ASSERT_TRUE(saved_a == a);    
}

TEST_F(IOBufTest, appender) {
    butil::IOBufAppender appender;
    ASSERT_EQ(0, appender.append("hello", 5));
    ASSERT_EQ("hello", appender.buf());
    ASSERT_EQ(0, appender.push_back(' '));
    ASSERT_EQ(0, appender.append("world", 5));
    ASSERT_EQ("hello world", appender.buf());
    butil::IOBuf buf2;
    appender.move_to(buf2);
    ASSERT_EQ("", appender.buf());
    ASSERT_EQ("hello world", buf2);
    std::string str;
    for (int i = 0; i < 10000; ++i) {
        char buf[128];
        int len = snprintf(buf, sizeof(buf), "1%d2%d3%d4%d5%d", i, i, i, i, i);
        appender.append(buf, len);
        str.append(buf, len);
    }
    ASSERT_EQ(str, appender.buf());
    butil::IOBuf buf3;
    appender.move_to(buf3);
    ASSERT_EQ("", appender.buf());
    ASSERT_EQ(str, buf3);
}

TEST_F(IOBufTest, appender_perf) {
    const size_t N1 = 100000;
    butil::Timer tm1;
    tm1.start();
    butil::IOBuf buf1;
    for (size_t i = 0; i < N1; ++i) {
        buf1.push_back(i);
    }
    tm1.stop();

    butil::Timer tm2;
    tm2.start();
    butil::IOBufAppender appender1;
    for (size_t i = 0; i < N1; ++i) {
        appender1.push_back(i);
    }
    tm2.stop();

    LOG(INFO) << "IOBuf.push_back=" << tm1.n_elapsed() / N1
              << "ns IOBufAppender.push_back=" << tm2.n_elapsed() / N1
              << "ns";

    const size_t N2 = 50000;
    const std::string s = "a repeatly appended string";
    std::string str2;
    butil::IOBuf buf2;
    tm1.start();
    for (size_t i = 0; i < N2; ++i) {
        buf2.append(s);
    }
    tm1.stop();

    tm2.start();
    butil::IOBufAppender appender2;
    for (size_t i = 0; i < N2; ++i) {
        appender2.append(s);
    }
    tm2.stop();

    butil::Timer tm3;
    tm3.start();
    for (size_t i = 0; i < N2; ++i) {
        str2.append(s);
    }
    tm3.stop();

    LOG(INFO) << "IOBuf.append=" << tm1.n_elapsed() / N2
              << "ns IOBufAppender.append=" << tm2.n_elapsed() / N2
              << "ns string.append=" << tm3.n_elapsed() / N2
              << "ns (string-length=" << s.size() << ')';
}

TEST_F(IOBufTest, printed_as_binary) {
    butil::IOBuf buf;
    std::string str;
    for (int i = 0; i < 256; ++i) {
        buf.push_back((char)i);
        str.push_back((char)i);
    }
    const char* const OUTPUT =
        "\\00\\01\\02\\03\\04\\05\\06\\07\\b\\t\\n\\0B\\0C\\r\\0E\\0F"
        "\\10\\11\\12\\13\\14\\15\\16\\17\\18\\19\\1A\\1B\\1C\\1D\\1E"
        "\\1F !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUV"
        "WXYZ[\\\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\\7F\\80\\81\\82"
        "\\83\\84\\85\\86\\87\\88\\89\\8A\\8B\\8C\\8D\\8E\\8F\\90\\91"
        "\\92\\93\\94\\95\\96\\97\\98\\99\\9A\\9B\\9C\\9D\\9E\\9F\\A0"
        "\\A1\\A2\\A3\\A4\\A5\\A6\\A7\\A8\\A9\\AA\\AB\\AC\\AD\\AE\\AF"
        "\\B0\\B1\\B2\\B3\\B4\\B5\\B6\\B7\\B8\\B9\\BA\\BB\\BC\\BD\\BE"
        "\\BF\\C0\\C1\\C2\\C3\\C4\\C5\\C6\\C7\\C8\\C9\\CA\\CB\\CC\\CD"
        "\\CE\\CF\\D0\\D1\\D2\\D3\\D4\\D5\\D6\\D7\\D8\\D9\\DA\\DB\\DC"
        "\\DD\\DE\\DF\\E0\\E1\\E2\\E3\\E4\\E5\\E6\\E7\\E8\\E9\\EA\\EB"
        "\\EC\\ED\\EE\\EF\\F0\\F1\\F2\\F3\\F4\\F5\\F6\\F7\\F8\\F9\\FA"
        "\\FB\\FC\\FD\\FE\\FF";
    std::ostringstream os;
    os << butil::ToPrintable(buf, 256);
    ASSERT_STREQ(OUTPUT, os.str().c_str());
    os.str("");
    os << butil::ToPrintable(str, 256);
    ASSERT_STREQ(OUTPUT, os.str().c_str());
}

TEST_F(IOBufTest, copy_to_string_from_iterator) {
    butil::IOBuf b0;
    for (size_t i = 0; i < 1 * 1024 * 1024lu; ++i) {
        b0.push_back(butil::fast_rand_in('a', 'z'));
    }
    butil::IOBuf b1(b0);
    butil::IOBufBytesIterator iter(b0);
    size_t nc = 0;
    while (nc < b0.length()) {
        size_t to_copy = butil::fast_rand_in(1024lu, 64 * 1024lu);
        butil::IOBuf b;
        b1.cutn(&b, to_copy);
        std::string s;
        const size_t copied = iter.copy_and_forward(&s, to_copy);
        ASSERT_GT(copied, 0u);
        ASSERT_TRUE(b.equals(s));
        nc += copied;
    }
    ASSERT_EQ(nc, b0.length());
}

static void* my_free_params = NULL;
static void my_free(void* m) {
    free(m);
    my_free_params = m;
}
    
TEST_F(IOBufTest, append_user_data_and_consume) {
    butil::IOBuf b0;
    const int REP = 16;
    const size_t len = REP * 256;
    char* data = (char*)malloc(len);
    for (int i = 0; i < 256; ++i) {
        for (int j = 0; j < REP; ++j) {
            data[i * REP + j] = (char)i;
        }
    }
    my_free_params = NULL;
    ASSERT_EQ(0, b0.append_user_data(data, len, my_free));
    ASSERT_EQ(1UL, b0._ref_num());
    butil::IOBuf::BlockRef r = b0._front_ref();
    ASSERT_EQ(1, butil::iobuf::block_shared_count(r.block));
    ASSERT_EQ(len, b0.size());
    std::string out;
    ASSERT_EQ(len, b0.cutn(&out, len));
    ASSERT_TRUE(b0.empty());
    ASSERT_EQ(data, my_free_params);
        
    ASSERT_EQ(len, out.size());
    // note: cannot memcmp with data which is already free-ed
    for (int i = 0; i < 256; ++i) {
        for (int j = 0; j < REP; ++j) {
            ASSERT_EQ((char)i, out[i * REP + j]);
        }
    }
}

TEST_F(IOBufTest, append_stateful_user_data) {
    butil::IOBuf b0;
    const int REP = 16;
    const size_t len = REP * 256;
    std::shared_ptr<char> mem(new char[len], std::default_delete<char[]>());
    std::weak_ptr<char> weaker = mem;
    ASSERT_EQ(1, mem.use_count());
    char* data = mem.get();
    for (int i = 0; i < 256; ++i) {
        for (int j = 0; j < REP; ++j) {
            data[i * REP + j] = (char)i;
        }
    }

    int incr_upon_destructrion = 0;

    struct Deleter {
        Deleter(std::shared_ptr<char> partial, int& incr) : partial(std::move(partial)), incr(&incr), allow_incr(false) {}
        ~Deleter() {
            if (allow_incr) (*incr)++;
        }
        Deleter(const Deleter&) { std::abort(); /*if copy, then crash*/ }
        Deleter(Deleter&&) noexcept = default;
        void operator()(void*) {
            partial.reset();
            allow_incr = true;
        }
        std::shared_ptr<char> partial;
        int* incr;
        bool allow_incr;
    };

    for (int i = 0; i < 256; i++) {
        std::shared_ptr<char> ptr(mem, data + i * REP);
        ASSERT_EQ(0, b0.append_user_data(data + i * REP, REP, Deleter{std::move(ptr), incr_upon_destructrion}));
    }
    ASSERT_EQ(256, b0._ref_num());
    ASSERT_EQ(257, mem.use_count());
    mem.reset();
    butil::IOBuf::BlockRef r = b0._front_ref();
    ASSERT_EQ(1, butil::iobuf::block_shared_count(r.block));
    ASSERT_EQ(len, b0.size());
    std::string out;
    ASSERT_EQ(len, b0.cutn(&out, len));
    ASSERT_TRUE(b0.empty());
    ASSERT_TRUE(weaker.expired());
    ASSERT_EQ(256, incr_upon_destructrion);

    ASSERT_EQ(len, out.size());
    // note: cannot memcmp with data which is already free-ed
    for (int i = 0; i < 256; ++i) {
        for (int j = 0; j < REP; ++j) {
            ASSERT_EQ((char)i, out[i * REP + j]);
        }
    }
}

TEST_F(IOBufTest, append_user_data_and_share) {
    butil::IOBuf b0;
    const int REP = 16;
    const size_t len = REP * 256;
    char* data = (char*)malloc(len);
    for (int i = 0; i < 256; ++i) {
        for (int j = 0; j < REP; ++j) {
            data[i * REP + j] = (char)i;
        }
    }
    my_free_params = NULL;
    ASSERT_EQ(0, b0.append_user_data(data, len, my_free));
    ASSERT_EQ(1UL, b0._ref_num());
    butil::IOBuf::BlockRef r = b0._front_ref();
    ASSERT_EQ(1, butil::iobuf::block_shared_count(r.block));
    ASSERT_EQ(len, b0.size());

    {
        butil::IOBuf bufs[256];
        for (int i = 0; i < 256; ++i) {
            ASSERT_EQ((size_t)REP, b0.cutn(&bufs[i], REP));
            ASSERT_EQ(len - (i+1) * REP, b0.size());
            if (i != 255) {
                ASSERT_EQ(1UL, b0._ref_num());
                butil::IOBuf::BlockRef r = b0._front_ref();
                ASSERT_EQ(i + 2, butil::iobuf::block_shared_count(r.block));
            } else {
                ASSERT_EQ(0UL, b0._ref_num());
                ASSERT_TRUE(b0.empty());
            }
        }
        ASSERT_EQ(NULL, my_free_params);
        for (int i = 0; i < 256; ++i) {
            std::string out = bufs[i].to_string();
            ASSERT_EQ((size_t)REP, out.size());
            for (int j = 0; j < REP; ++j) {
                ASSERT_EQ((char)i, out[j]);
            }
        }
    }
    ASSERT_EQ(data, my_free_params);
}

TEST_F(IOBufTest, append_user_data_with_meta) {
    butil::IOBuf b0;
    const int REP = 16;
    const size_t len = 256;
    char* data[REP];
    for (int i = 0; i < REP; ++i) {
        data[i] = (char*)malloc(len);
        ASSERT_EQ(0, b0.append_user_data_with_meta(data[i], len, my_free, i));
    }
    for (int i = 0; i < REP; ++i) {
        ASSERT_EQ(i, b0.get_first_data_meta());
        butil::IOBuf out;
        ASSERT_EQ(len / 2, b0.cutn(&out, len / 2));
        ASSERT_EQ(i, b0.get_first_data_meta());
        ASSERT_EQ(len / 2, b0.cutn(&out, len / 2));
    }
}

TEST_F(IOBufTest, share_tls_block) {
    butil::iobuf::remove_tls_block_chain();
    butil::IOBuf::Block* b = butil::iobuf::acquire_tls_block();
    ASSERT_EQ(0u, butil::iobuf::block_size(b));

    butil::IOBuf::Block* b2 = butil::iobuf::share_tls_block();
    butil::IOBuf buf;
    for (size_t i = 0; i < butil::iobuf::block_cap(b2); i++) {
        buf.push_back('x');
    }
    // after pushing to b2, b2 is full but it is still head of tls block.
    ASSERT_NE(b, b2);
    butil::iobuf::release_tls_block_chain(b);
    ASSERT_EQ(b, butil::iobuf::share_tls_block());
    // After releasing b, now tls block is b(not full) -> b2(full) -> NULL
    for (size_t i = 0; i < butil::iobuf::block_cap(b); i++) {
        buf.push_back('x');
    }
    // now tls block is b(full) -> b2(full) -> NULL
    butil::IOBuf::Block* head_block = butil::iobuf::share_tls_block();
    ASSERT_EQ(0u, butil::iobuf::block_size(head_block));
    ASSERT_NE(b, head_block);
    ASSERT_NE(b2, head_block);
}

TEST_F(IOBufTest, acquire_tls_block) {
    butil::iobuf::remove_tls_block_chain();
    butil::IOBuf::Block* b = butil::iobuf::acquire_tls_block();
    const size_t block_cap = butil::iobuf::block_cap(b);
    butil::IOBuf buf;
    for (size_t i = 0; i < block_cap; i++) {
        buf.append("x");
    }
    ASSERT_EQ(1, butil::iobuf::get_tls_block_count());
    butil::IOBuf::Block* head = butil::iobuf::get_tls_block_head();
    ASSERT_EQ(butil::iobuf::block_cap(head), butil::iobuf::block_size(head));
    butil::iobuf::release_tls_block_chain(b);
    ASSERT_EQ(2, butil::iobuf::get_tls_block_count());
    for (size_t i = 0; i < block_cap; i++) {
        buf.append("x");
    }
    ASSERT_EQ(2, butil::iobuf::get_tls_block_count());
    head = butil::iobuf::get_tls_block_head();
    ASSERT_EQ(butil::iobuf::block_cap(head), butil::iobuf::block_size(head));
    b = butil::iobuf::acquire_tls_block();
    ASSERT_EQ(0, butil::iobuf::get_tls_block_count());
    ASSERT_NE(butil::iobuf::block_cap(b), butil::iobuf::block_size(b));
}

TEST_F(IOBufTest, reserve_aligned) {
    {
        butil::IOReserveAlignedBuf buf(16);
        auto area = buf.reserve(1024);
        ASSERT_NE(area, butil::IOBuf::INVALID_AREA);
        butil::IOBufAsZeroCopyInputStream wrapper(buf);
        const void* data;
        int size;
        int total_size = 0;
        while (wrapper.Next(&data, &size)) {
            ASSERT_EQ(reinterpret_cast<uintptr_t>(data) % 16, 0);
            ASSERT_EQ(size % 16, 0);
            total_size += size;
        }
        ASSERT_EQ(total_size, 1024);
    }
    {
        butil::IOReserveAlignedBuf buf(4096);
        auto area = buf.reserve(1024);
        ASSERT_NE(area, butil::IOBuf::INVALID_AREA);
        butil::IOBufAsZeroCopyInputStream wrapper(buf);
        const void* data;
        int size;
        int total_size = 0;
        while (wrapper.Next(&data, &size)) {
            ASSERT_EQ(reinterpret_cast<uintptr_t>(data) % 4096, 0);
            ASSERT_EQ(size % 4096, 0);
            total_size += size;
        }
        ASSERT_EQ(total_size, 4096);
    }
    {
        butil::IOReserveAlignedBuf buf(4096);
        auto area = buf.reserve(8191);
        ASSERT_NE(area, butil::IOBuf::INVALID_AREA);
        butil::IOBufAsZeroCopyInputStream wrapper(buf);
        const void* data;
        int size;
        int total_size = 0;
        while (wrapper.Next(&data, &size)) {
            ASSERT_EQ(reinterpret_cast<uintptr_t>(data) % 4096, 0);
            ASSERT_EQ(size % 4096, 0);
            total_size += size;
        }
        ASSERT_EQ(total_size, 8192);
    }
    {
        butil::IOReserveAlignedBuf buf(4096);
        auto area = buf.reserve(4096 * 10 - 1);
        ASSERT_NE(area, butil::IOBuf::INVALID_AREA);
        butil::IOBufAsZeroCopyInputStream wrapper(buf);
        const void* data;
        int size;
        int total_size = 0;
        while (wrapper.Next(&data, &size)) {
            ASSERT_EQ(reinterpret_cast<uintptr_t>(data) % 4096, 0);
            ASSERT_EQ(size % 4096, 0);
            total_size += size;
        }
        ASSERT_EQ(total_size, 4096 * 10);
    }
    {
        butil::IOReserveAlignedBuf buf(4095);
        auto area = buf.reserve(4096);
        ASSERT_EQ(area, butil::IOBuf::INVALID_AREA);
    }
    {
        butil::IOReserveAlignedBuf buf(8192);
        auto area = buf.reserve(4096 * 10 + 1);
        ASSERT_NE(area, butil::IOBuf::INVALID_AREA);
        butil::IOBufAsZeroCopyInputStream wrapper(buf);
        const void* data;
        int size;
        int total_size = 0;
        while (wrapper.Next(&data, &size)) {
            ASSERT_EQ(reinterpret_cast<uintptr_t>(data) % 4096, 0);
            ASSERT_EQ(size % 4096, 0);
            total_size += size;
        }
        ASSERT_EQ(total_size, 4096 * 10 + 8192);
    }
    {
        butil::IOReserveAlignedBuf buf(4096);
        auto area = buf.reserve(1024 * 1024 * 3);
        ASSERT_NE(area, butil::IOBuf::INVALID_AREA);
        butil::IOBufAsZeroCopyInputStream wrapper(buf);
        const void* data;
        int size;
        int count = 0;
        int total_size = 0;
        std::stringstream ss;
        while (wrapper.Next(&data, &size)) {
            ASSERT_EQ(reinterpret_cast<uintptr_t>(data) % 4096, 0);
            ASSERT_EQ(size % 4096, 0);
            std::string str(size, 'A' + count++);
            ss << str;
            std::memcpy(const_cast<void*>(data), str.data(), str.size());
            total_size += size;
        }
        ASSERT_EQ(total_size, 3145728);
        ASSERT_EQ(ss.str(), buf.to_string());
    }
}

TEST_F(IOBufTest, single_iobuf) {
    butil::IOBuf buf1;
    // It will be freed by IOBuf.
    char *usr_str = (char *)malloc(16);
    memset(usr_str, 0, 16);
    char src_str[] = "abcdefgh12345678";
    size_t total_len = sizeof(src_str);
    strncpy(usr_str, src_str + 8, total_len - 8);
    buf1.append(src_str, 8);
    buf1.append_user_data(usr_str, total_len - 8, NULL);
    ASSERT_EQ(2, buf1.backing_block_num());
    butil::SingleIOBuf sbuf;
    ASSERT_EQ(0, sbuf.backing_block_num());
    sbuf.assign(buf1, total_len);
    ASSERT_EQ(1, sbuf.backing_block_num());
    size_t s_len = sbuf.get_length();
    ASSERT_EQ(s_len, total_len);
    const char* str = (const char*) sbuf.get_begin();
    int ret = strcmp(str, src_str);
    ASSERT_EQ(0, ret);
    butil::IOBuf buf2;
    sbuf.append_to(&buf2);
    ASSERT_EQ(buf2.length(), total_len);
    butil::SingleIOBuf sbuf2;
    sbuf2.swap(sbuf);
    ASSERT_EQ(sbuf.get_length(), 0);
    ASSERT_EQ(sbuf2.get_length(), total_len);
    sbuf2.reset();
    ASSERT_EQ(0, sbuf2.get_length());
    
    void* buf = sbuf.allocate(1024);
    ASSERT_TRUE(NULL != buf);
    buf = sbuf.reallocate_downward(16384, 0, 0);
    ASSERT_TRUE(NULL != buf);
    s_len = sbuf.get_length();
    ASSERT_EQ(16384, s_len);

    butil::IOBuf::BlockRef ref = sbuf.get_cur_ref();
    butil::SingleIOBuf sbuf3(ref);
    s_len = sbuf3.get_length();
    ASSERT_EQ(16384, s_len);
    sbuf.deallocate(buf);

    errno = 0;
    void *null_buf = sbuf3.reallocate_downward(s_len - 1, 0, 0);
    ASSERT_EQ(null_buf, nullptr);

    uint32_t old_size = sbuf3.get_length();
    void *p = sbuf3.reallocate_downward(old_size + 16, 0, old_size); 
    ASSERT_TRUE(p != nullptr);
    old_size = sbuf3.get_length();
    p = sbuf3.reallocate_downward(old_size + 16, old_size, 0);
    ASSERT_TRUE(p != nullptr);
}

// Regression tests for https://github.com/apache/brpc/issues/3243
//
// A duplicate return of a block that's already in the TLS free list can create
// either a self-loop (when the block is block_head) or a longer cycle (when
// the block already exists deeper in the list).  Any later traversal then
// spins forever.  Run these tests in a dedicated pthread so the main thread's
// TLS remains untouched.

static bool tls_block_chain_has_cycle() {
    butil::IOBuf::Block* slow = butil::iobuf::get_tls_block_head();
    butil::IOBuf::Block* fast = slow;
    while (fast != NULL) {
        fast = butil::iobuf::get_portal_next(fast);
        if (fast == NULL) {
            return false;
        }
        slow = butil::iobuf::get_portal_next(slow);
        fast = butil::iobuf::get_portal_next(fast);
        if (slow == fast) {
            return true;
        }
    }
    return false;
}

static void dec_ref_distinct_blocks(butil::IOBuf::Block* b1,
                                    butil::IOBuf::Block* b2,
                                    butil::IOBuf::Block* b3 = NULL) {
    if (b1 != NULL) {
        b1->dec_ref();
    }
    if (b2 != NULL && b2 != b1) {
        b2->dec_ref();
    }
    if (b3 != NULL && b3 != b1 && b3 != b2) {
        b3->dec_ref();
    }
}

static void cleanup_corrupted_tls_chain(int drain_times) {
    butil::IOBuf::Block* b1 = NULL;
    butil::IOBuf::Block* b2 = NULL;
    butil::IOBuf::Block* b3 = NULL;
    if (drain_times >= 1) {
        b1 = butil::iobuf::acquire_tls_block();
    }
    if (drain_times >= 2) {
        b2 = butil::iobuf::acquire_tls_block();
    }
    if (drain_times >= 3) {
        b3 = butil::iobuf::acquire_tls_block();
    }
    dec_ref_distinct_blocks(b1, b2, b3);
}

static void* double_return_release_tls_block_head_thread(void* arg) {
    bool* has_cycle = static_cast<bool*>(arg);
    butil::iobuf::remove_tls_block_chain();

    butil::IOBuf::Block* b = butil::iobuf::acquire_tls_block();
    if (!b) {
        return NULL;
    }
    butil::iobuf::release_tls_block(b);
    butil::iobuf::release_tls_block(b);

    if (tls_block_chain_has_cycle()) {
        *has_cycle = true;
        cleanup_corrupted_tls_chain(2);
    } else {
        butil::iobuf::remove_tls_block_chain();
    }
    return NULL;
}

TEST_F(IOBufTest, regression_3243_release_tls_block_head_no_cycle) {
    bool has_cycle = false;
    pthread_t tid;
    ASSERT_EQ(0, pthread_create(&tid, NULL,
                                double_return_release_tls_block_head_thread,
                                &has_cycle));
    ASSERT_EQ(0, pthread_join(tid, NULL));

    EXPECT_FALSE(has_cycle)
        << "release_tls_block() created a cycle when the same block was "
           "returned twice while already cached in TLS.  (GitHub issue #3243)";
}

static void* double_return_release_tls_block_non_head_thread(void* arg) {
    bool* has_cycle = static_cast<bool*>(arg);
    butil::iobuf::remove_tls_block_chain();

    butil::IOBuf::Block* tail = butil::iobuf::acquire_tls_block();
    butil::IOBuf::Block* head = butil::iobuf::acquire_tls_block();
    if (!tail || !head) {
        dec_ref_distinct_blocks(tail, head);
        return NULL;
    }

    butil::iobuf::release_tls_block(tail);
    butil::iobuf::release_tls_block(head);
    // TLS: head -> tail -> NULL. Returning tail again used to create
    // tail -> head -> tail.
    butil::iobuf::release_tls_block(tail);

    if (tls_block_chain_has_cycle()) {
        *has_cycle = true;
        cleanup_corrupted_tls_chain(3);
    } else {
        butil::iobuf::remove_tls_block_chain();
    }
    return NULL;
}

TEST_F(IOBufTest, regression_3243_release_tls_block_non_head_no_cycle) {
    bool has_cycle = false;
    pthread_t tid;
    ASSERT_EQ(0, pthread_create(&tid, NULL,
                                double_return_release_tls_block_non_head_thread,
                                &has_cycle));
    ASSERT_EQ(0, pthread_join(tid, NULL));

    EXPECT_FALSE(has_cycle)
        << "release_tls_block() created a cycle when a block already present "
           "deeper in the TLS list was returned again.  "
           "(GitHub issue #3243)";
}

static void* double_return_release_tls_block_chain_head_thread(void* arg) {
    bool* has_cycle = static_cast<bool*>(arg);
    butil::iobuf::remove_tls_block_chain();

    butil::IOBuf::Block* b = butil::iobuf::acquire_tls_block();
    if (!b) {
        return NULL;
    }
    butil::iobuf::release_tls_block(b);
    b->u.portal_next = NULL;
    butil::iobuf::release_tls_block_chain(b);

    if (tls_block_chain_has_cycle()) {
        *has_cycle = true;
        cleanup_corrupted_tls_chain(2);
    } else {
        butil::iobuf::remove_tls_block_chain();
    }
    return NULL;
}

TEST_F(IOBufTest, regression_3243_release_tls_block_chain_head_no_cycle) {
    bool has_cycle = false;
    pthread_t tid;
    ASSERT_EQ(0, pthread_create(&tid, NULL,
                                double_return_release_tls_block_chain_head_thread,
                                &has_cycle));
    ASSERT_EQ(0, pthread_join(tid, NULL));

    EXPECT_FALSE(has_cycle)
        << "release_tls_block_chain() created a cycle when the returned chain "
           "overlapped the TLS head.  (GitHub issue #3243)";
}

static void* double_return_release_tls_block_chain_non_head_thread(void* arg) {
    bool* has_cycle = static_cast<bool*>(arg);
    butil::iobuf::remove_tls_block_chain();

    butil::IOBuf::Block* tail = butil::iobuf::acquire_tls_block();
    butil::IOBuf::Block* head = butil::iobuf::acquire_tls_block();
    if (!tail || !head) {
        dec_ref_distinct_blocks(tail, head);
        return NULL;
    }

    butil::iobuf::release_tls_block(tail);
    butil::iobuf::release_tls_block(head);
    // TLS: head -> tail -> NULL. Returning the single-node chain [tail]
    // again used to create tail -> head -> tail.
    tail->u.portal_next = NULL;
    butil::iobuf::release_tls_block_chain(tail);

    if (tls_block_chain_has_cycle()) {
        *has_cycle = true;
        cleanup_corrupted_tls_chain(3);
    } else {
        butil::iobuf::remove_tls_block_chain();
    }
    return NULL;
}

TEST_F(IOBufTest, regression_3243_release_tls_block_chain_non_head_no_cycle) {
    bool has_cycle = false;
    pthread_t tid;
    ASSERT_EQ(0, pthread_create(&tid, NULL,
                                double_return_release_tls_block_chain_non_head_thread,
                                &has_cycle));
    ASSERT_EQ(0, pthread_join(tid, NULL));

    EXPECT_FALSE(has_cycle)
        << "release_tls_block_chain() created a cycle when the returned chain "
           "contained a block already present deeper in TLS.  "
           "(GitHub issue #3243)";
}

struct PartialOverlapResult {
    bool has_cycle;
    int tls_block_count;
};

static void* partial_overlap_release_tls_block_chain_thread(void* arg) {
    PartialOverlapResult* result = static_cast<PartialOverlapResult*>(arg);
    result->has_cycle = false;
    result->tls_block_count = -1;
    butil::iobuf::remove_tls_block_chain();

    butil::IOBuf::Block* tail = butil::iobuf::acquire_tls_block();
    butil::IOBuf::Block* head = butil::iobuf::acquire_tls_block();
    butil::IOBuf::Block* prefix = butil::iobuf::acquire_tls_block();
    if (!tail || !head || !prefix) {
        dec_ref_distinct_blocks(tail, head, prefix);
        return NULL;
    }

    butil::iobuf::release_tls_block(tail);
    butil::iobuf::release_tls_block(head);
    // TLS: head -> tail -> NULL. Returning prefix -> tail should preserve
    // prefix and avoid both the tail->head->tail cycle and leaking prefix.
    prefix->u.portal_next = tail;
    butil::iobuf::release_tls_block_chain(prefix);

    result->has_cycle = tls_block_chain_has_cycle();
    result->tls_block_count = butil::iobuf::get_tls_block_count();
    if (result->has_cycle) {
        cleanup_corrupted_tls_chain(3);
    } else {
        butil::iobuf::remove_tls_block_chain();
    }
    return NULL;
}

TEST_F(IOBufTest, regression_3243_release_tls_block_chain_partial_overlap_keeps_prefix) {
    install_debug_allocator();

    PartialOverlapResult result;
    result.has_cycle = false;
    result.tls_block_count = -1;

    pthread_t tid;
    ASSERT_EQ(0, pthread_create(&tid, NULL,
                                partial_overlap_release_tls_block_chain_thread,
                                &result));
    ASSERT_EQ(0, pthread_join(tid, NULL));

    EXPECT_FALSE(result.has_cycle)
        << "release_tls_block_chain() created a cycle when a unique prefix "
           "was returned ahead of a block already cached in TLS.  "
           "(GitHub issue #3243)";
    EXPECT_EQ(3, result.tls_block_count)
        << "release_tls_block_chain() dropped the unique prefix when the "
           "returned chain overlapped the TLS list.  (GitHub issue #3243)";
}

// Reproduce the issue through IOBufAsZeroCopyOutputStream::BackUp().  BackUp()
// eagerly returns _cur_block to TLS.  A subsequent release of the same pointer
// used to create a self-loop at the head.
static void* backup_double_return_thread(void* arg) {
    bool* has_cycle = static_cast<bool*>(arg);
    butil::iobuf::remove_tls_block_chain();

    butil::IOBuf buf;
    {
        butil::IOBufAsZeroCopyOutputStream stream(&buf);
        void* data = NULL;
        int size = 0;
        EXPECT_TRUE(stream.Next(&data, &size));
        stream.BackUp(size);

        butil::IOBuf::Block* head = butil::iobuf::get_tls_block_head();
        EXPECT_TRUE(head != NULL);
        butil::iobuf::release_tls_block(head);

        if (tls_block_chain_has_cycle()) {
            *has_cycle = true;
            cleanup_corrupted_tls_chain(2);
        }
    }
    if (!*has_cycle) {
        butil::iobuf::remove_tls_block_chain();
    }
    return NULL;
}

TEST_F(IOBufTest, regression_3243_backup_then_double_release_no_cycle) {
    bool has_cycle = false;
    pthread_t tid;
    ASSERT_EQ(0, pthread_create(&tid, NULL,
                                backup_double_return_thread, &has_cycle));
    ASSERT_EQ(0, pthread_join(tid, NULL));

    EXPECT_FALSE(has_cycle)
        << "After IOBufAsZeroCopyOutputStream::BackUp() returned a block to "
           "TLS, a second release_tls_block() created a cycle.  "
           "(GitHub issue #3243)";
}

} // namespace