Optimize parsing, filtering, and rendering performance (#27)

## Summary
This PR reduces allocation and CPU overhead across parsing, filtering,
query execution, and table rendering in `cirup_core`.

Highlights:
- Replace regex-backed text filter compilation and matching with a
purpose-built matcher for the supported pattern subset.
- Replace `prettytable-rs` table rendering with a manual ASCII formatter
while preserving the existing output layout.
- Remove `dot_json`-based JSON flattening in favor of direct recursive
flattening.
- Replace the RESTEXT regex parser with a manual parser and direct
writer.
- Reduce RESX escaping and parsing allocations by writing escapes
directly into output buffers and iterating parsed nodes directly.
- Reuse fast in-memory query execution for rusqlite-backed queries and
avoid extra row cloning when reading DB results.
- Preallocate file reads and avoid redundant UTF-8 output copies when
writing resource files.

## Benchmark Highlights
- Query filter compilation (`5,000` key patterns + `5,000` value
patterns): `~1.251s -> ~2.451ms`
- Filter pass on `50,000` resources with key and value filters: `~2.57ms
-> ~1.71ms`
- Repeated resource table rendering (`20,000` iterations): `~102.6ms ->
~13.3ms`
- Repeated report table rendering (`20,000` iterations): `~193.1ms ->
~26.5ms`

## Validation
- `cargo fmt --all`
- `cargo test --workspace`
- `cargo clippy --workspace --all-targets`

Author: mamoreau-devolutions

Cargo.lock

@@ -10,14 +10,13 @@ turso-rust = ["dep:tokio", "dep:turso", "dep:libsql"]
 rusqlite-c = ["dep:rusqlite"]
 
 [dependencies]
-regex = "1.0"
 serde = { version = "1.0", features = ["derive"] }
 xml-rs = "0.8.0"
 dot_json = "0.2.0"
 lazy_static = "1.0.0"
-prettytable-rs = "^0.10"
 log = "0.4"
 sha2 = "0.10"
+unicode-width = "0.2"
 
 [dependencies.uuid]
 version = "0.6"

cirup_core/Cargo.toml

@@ -4,6 +4,8 @@ use std::path::Path;
 
 use std::collections::HashMap;
 use std::sync::Mutex;
+#[cfg(test)]
+use std::time::Instant;
 
 use sha2::{Digest, Sha256};
 
@@ -50,8 +52,14 @@ pub(crate) fn load_string_from_file(filename: &str) -> Result<String, Box<dyn Er
     if let Some(text) = vfile_get(filename) {
         return Ok(text);
     }
+
     let mut file = fs::File::open(filename)?;
-    let mut text = String::new();
+    let capacity = file
+        .metadata()
+        .ok()
+        .and_then(|metadata| usize::try_from(metadata.len()).ok())
+        .unwrap_or(0);
+    let mut text = String::with_capacity(capacity);
     file.read_to_string(&mut text)?;
     Ok(text)
 }
@@ -74,13 +82,14 @@ fn should_write_output(output_hash: [u8; 32], existing_bytes: Option<&[u8]>, tou
     output_hash != sha256_hash(existing_bytes)
 }
 
-fn encode_utf8(text: &str, output_encoding: OutputEncoding) -> Vec<u8> {
+fn encode_utf8_owned(text: String, output_encoding: OutputEncoding) -> Vec<u8> {
     match output_encoding {
-        OutputEncoding::Utf8NoBom => text.as_bytes().to_vec(),
+        OutputEncoding::Utf8NoBom => text.into_bytes(),
         OutputEncoding::Utf8Bom => {
+            let text = text.into_bytes();
             let mut output = Vec::with_capacity(UTF8_BOM.len() + text.len());
             output.extend_from_slice(&UTF8_BOM);
-            output.extend_from_slice(text.as_bytes());
+            output.extend_from_slice(&text);
             output
         }
     }
@@ -95,17 +104,17 @@ fn output_bytes_for_format(
         FormatType::Json => {
             let file_format = JsonFileFormat {};
             let text = file_format.write_to_str(resources);
-            encode_utf8(&text, output_encoding)
+            encode_utf8_owned(text, output_encoding)
         }
         FormatType::Resx => {
             let file_format = ResxFileFormat {};
             let text = file_format.write_to_str(resources);
-            encode_utf8(&text, output_encoding)
+            encode_utf8_owned(text, output_encoding)
         }
         FormatType::Restext => {
             let file_format = RestextFileFormat {};
             let text = file_format.write_to_str(resources);
-            encode_utf8(&text, output_encoding)
+            encode_utf8_owned(text, output_encoding)
         }
         FormatType::Unknown => Vec::new(),
     }
@@ -355,3 +364,31 @@ fn would_save_resource_file_reports_true_for_missing_output() {
 
     assert!(would_write);
 }
+
+#[test]
+#[ignore = "benchmark: run manually with --ignored --nocapture"]
+#[allow(clippy::print_stdout)]
+fn benchmark_output_bytes_for_format_large_input() {
+    let resources = (0..50_000usize)
+        .map(|index| Resource::new(&format!("group{index}.key{}", index % 13), &format!("value{index}")))
+        .collect::<Vec<_>>();
+
+    let started = Instant::now();
+    let utf8_no_bom = output_bytes_for_format(FormatType::Json, &resources, OutputEncoding::Utf8NoBom);
+    let utf8_no_bom_elapsed = started.elapsed();
+
+    let started = Instant::now();
+    let utf8_bom = output_bytes_for_format(FormatType::Json, &resources, OutputEncoding::Utf8Bom);
+    let utf8_bom_elapsed = started.elapsed();
+
+    assert!(utf8_no_bom.len() < utf8_bom.len());
+
+    println!(
+        "output-bytes benchmark: resources={} utf8_no_bom_bytes={} utf8_bom_bytes={} no_bom={:?} bom={:?}",
+        resources.len(),
+        utf8_no_bom.len(),
+        utf8_bom.len(),
+        utf8_no_bom_elapsed,
+        utf8_bom_elapsed
+    );
+}

cirup_core/src/file.rs

@@ -1,10 +1,10 @@
-extern crate dot_json;
 extern crate serde;
 extern crate serde_json;
 
-use dot_json::value_to_dot;
 use serde::Serialize;
 use serde_json::{Map, Value};
+#[cfg(test)]
+use std::time::Instant;
 
 use crate::Resource;
 use crate::file::FileFormat;
@@ -14,23 +14,37 @@ use std::error::Error;
 pub(crate) struct JsonFileFormat {}
 
 fn json_dot_insert(root_map: &mut Map<String, Value>, name: &str, value: &str) {
-    if let Some(dot_index) = name.find('.') {
-        let root_path = &name[0..dot_index];
-        let child_path = &name[dot_index + 1..name.len()];
+    if let Some((root_path, child_path)) = name.split_once('.') {
+        let child_value = root_map
+            .entry(root_path.to_owned())
+            .or_insert_with(|| Value::Object(Map::new()));
 
-        if !root_map.contains_key(root_path) {
-            let child_map: Map<String, Value> = Map::new();
-            root_map.insert(root_path.to_owned(), Value::Object(child_map));
-        }
-
-        if let Some(Value::Object(child_map)) = root_map.get_mut(root_path) {
+        if let Value::Object(child_map) = child_value {
             json_dot_insert(child_map, child_path, value);
         }
     } else {
         root_map.insert(name.to_owned(), Value::String(value.to_owned()));
     }
 }
 
+fn flatten_json_value(value: &Value, path: &mut String, resources: &mut Vec<Resource>) {
+    match value {
+        Value::Object(object) => {
+            for (key, child_value) in object {
+                let prefix_len = path.len();
+                if prefix_len > 0 {
+                    path.push('.');
+                }
+                path.push_str(key);
+                flatten_json_value(child_value, path, resources);
+                path.truncate(prefix_len);
+            }
+        }
+        Value::String(text) => resources.push(Resource::new(path, text)),
+        _ => {}
+    }
+}
+
 fn json_to_string_pretty(value: &Map<String, Value>) -> String {
     let writer = Vec::new();
     let formatter = serde_json::ser::PrettyFormatter::with_indent(b"    ");
@@ -47,17 +61,18 @@ impl FileFormat for JsonFileFormat {
     fn parse_from_str(&self, text: &str) -> Result<Vec<Resource>, Box<dyn Error>> {
         let mut resources: Vec<Resource> = Vec::new();
         let root_value: Value = serde_json::from_str(text)?;
-        let root_value_dot = value_to_dot(&root_value);
-        let root_object_dot = match root_value_dot.as_object() {
+        let root_object = match root_value.as_object() {
             Some(object) => object,
-            None => Err("json dot value is not an object")?,
+            None => Err("json value is not an object")?,
         };
-        for (key, value) in root_object_dot.iter() {
-            if let Some(value) = value.as_str() {
-                let resource = Resource::new(key.as_str(), value);
-                resources.push(resource);
-            }
+
+        let mut path = String::new();
+        for (key, value) in root_object {
+            path.clear();
+            path.push_str(key);
+            flatten_json_value(value, &mut path, &mut resources);
         }
+
         Ok(resources)
     }
 
@@ -161,3 +176,42 @@ fn test_json_write() {
     //println!("{}", expected_text);
     assert_eq!(actual_text, expected_text);
 }
+
+#[test]
+#[ignore = "benchmark: run manually with --ignored --nocapture"]
+#[allow(clippy::print_stdout)]
+fn benchmark_json_parse_and_write_large_input() {
+    let file_format = JsonFileFormat {};
+    let repetitions = 5_000usize;
+    let mut resources = Vec::with_capacity(repetitions * 6);
+
+    for index in 0..repetitions {
+        let prefix = format!("group{index}");
+        resources.push(Resource::new(&format!("{prefix}.lblBoat"), "I'm on a boat."));
+        resources.push(Resource::new(&format!("{prefix}.lblYolo"), "You only live once"));
+        resources.push(Resource::new(&format!("{prefix}.lblDogs"), "Who let the dogs out?"));
+        resources.push(Resource::new(&format!("{prefix}.language.en"), "English"));
+        resources.push(Resource::new(&format!("{prefix}.language.fr"), "French"));
+        resources.push(Resource::new(&format!("{prefix}.very.deep.object"), "value"));
+    }
+
+    let started = Instant::now();
+    let written = file_format.write_to_str(&resources);
+    let write_elapsed = started.elapsed();
+
+    let started = Instant::now();
+    let reparsed = file_format
+        .parse_from_str(&written)
+        .unwrap_or_else(|e| panic!("json benchmark parse failed: {}", e));
+    let parse_elapsed = started.elapsed();
+
+    assert_eq!(reparsed.len(), resources.len());
+
+    println!(
+        "json benchmark: resources={} bytes={} write={:?} parse={:?}",
+        resources.len(),
+        written.len(),
+        write_elapsed,
+        parse_elapsed
+    );
+}

cirup_core/src/json.rs

@@ -1,4 +1,3 @@
-extern crate regex;
 extern crate treexml;
 extern crate uuid;
 
@@ -10,9 +9,6 @@ extern crate serde_json;
 #[macro_use]
 extern crate log;
 
-#[macro_use]
-extern crate prettytable;
-
 #[macro_use]
 extern crate lazy_static;