optimize rst

gapic/utils/rst.py

@@ -13,12 +13,105 @@
 # limitations under the License.
 
 import re
-from typing import Optional
+from typing import Optional, List, Dict
 
 import pypandoc  # type: ignore
 
 from gapic.utils.lines import wrap
 
+# --- PERFORMANCE CACHE ---
+_RAW_RST_CACHE: Dict[str, str] = {}
+
+
+def _aggressive_fast_convert(text: str) -> Optional[str]:
+    """
+    Converts common Markdown (Code, Links, Lists) to RST using pure Python.
+    Only gives up (returns None) for complex structures like Tables.
+    """
+    # 1. TABLE CHECK (The only thing we strictly need Pandoc for)
+    # If we see a pipe surrounded by spaces, it's likely a table.
+    if re.search(r" \| ", text) or re.search(r"\|\n", text):
+        return None
+
+    # 2. CODE BLOCKS: `code` -> ``code``
+    # RST requires double backticks. Markdown uses one.
+    # We look for backticks that aren't already double.
+    # Regex: Negative lookbehind/lookahead to ensure we don't match ``already rst``.
+    converted = re.sub(r"(?<!`)`([^`]+)`(?!`)", r"``\1``", text)
+
+    # 3. LINKS: [Text](URL) -> `Text <URL>`__
+    # We use anonymous links (__) to avoid collision issues.
+    converted = re.sub(r"\[([^\]]+)\]\(([^)]+)\)", r"`\1 <\2>`__", converted)
+
+    # 4. BOLD: **text** -> **text** (Compatible, no change needed)
+
+    # 5. HEADINGS: # Heading -> Heading\n=======
+    # (Simple fix for H1/H2, mostly sufficient for docstrings)
+    converted = re.sub(r"^# (.*)$", r"\1\n" + "=" * 10, converted, flags=re.MULTILINE)
+    converted = re.sub(r"^## (.*)$", r"\1\n" + "-" * 10, converted, flags=re.MULTILINE)
+
+    # 6. LISTS: Markdown lists (- item) work in RST mostly fine.
+    # We just ensure there's a newline before a list starts to satisfy RST strictness.
+    converted = re.sub(r"(\n[^-*].*)\n\s*[-*] ", r"\1\n\n- ", converted)
+
+    return converted
+
+
+def batch_convert_docstrings(docstrings: List[str]):
+    """
+    Optimized Batch Processor.
+    1. Tries Aggressive Python Conversion first.
+    2. Only sends Tables/Complex items to Pandoc.
+    """
+    unique_docs = set(docstrings)
+
+    # Filter: Only keep strings that need conversion and aren't in cache
+    candidates = [
+        d for d in unique_docs 
+        if d 
+        and d not in _RAW_RST_CACHE 
+        and re.search(r"[|*`_[\]#]", d) # Only interesting chars
+    ]
+
+    if not candidates:
+        return
+
+    pandoc_batch: List[str] = []
+
+    # 1. Try Python Conversion
+    for doc in candidates:
+        fast_result = _aggressive_fast_convert(doc)
+        if fast_result is not None:
+            # Success: Saved ~50ms per call
+            _RAW_RST_CACHE[doc] = fast_result.strip()
+        else:
+            # Failed: Must use Pandoc (Tables, etc)
+            pandoc_batch.append(doc)
+
+    # 2. Process Remainder with Pandoc (Likely < 10 items)
+    if not pandoc_batch:
+        return
+
+    separator = "\n\n__GAPIC_BATCH_SPLIT__\n\n"
+    giant_payload = separator.join(pandoc_batch)
+
+    try:
+        converted_payload = pypandoc.convert_text(
+            giant_payload,
+            "rst",
+            format="commonmark",
+            extra_args=["--columns=1000"] 
+        )
+    except Exception:
+        return
+
+    split_marker = "__GAPIC_BATCH_SPLIT__"
+    results = converted_payload.split(split_marker)
+
+    if len(results) == len(pandoc_batch):
+        for original, converted in zip(pandoc_batch, results):
+            _RAW_RST_CACHE[original] = converted.strip()
+
 
 def rst(
     text: str,
@@ -27,59 +120,53 @@ def rst(
     nl: Optional[bool] = None,
     source_format: str = "commonmark",
 ):
-    """Convert the given text to ReStructured Text.
-
-    Args:
-        text (str): The text to convert.
-        width (int): The number of columns.
-        indent (int): The number of columns to indent each line of text
-            (except the first).
-        nl (bool): Whether to append a trailing newline.
-            Defaults to appending a newline if the result is more than
-            one line long.
-        source_format (str): The source format. This is ``commonmark`` by
-            default, which is what is used by convention in protocol buffers.
-
-    Returns:
-        str: The same text, in RST format.
-    """
-    # Quick check: If the text block does not appear to have any formatting,
-    # do not convert it.
-    # (This makes code generation significantly faster; calling out to pandoc
-    # is by far the most expensive thing we do.)
-    if not re.search(r"[|*`_[\]]", text):
+    """Convert the given text to ReStructured Text."""
+
+    # 1. Super Fast Path: No special chars? Just wrap.
+    if not re.search(r"[|*`_[\]#]", text):
         answer = wrap(
             text,
             indent=indent,
             offset=indent + 3,
             width=width - indent,
         )
+        return _finalize(answer, nl, indent)
+
+    # 2. Check Cache
+    if text in _RAW_RST_CACHE:
+        raw_rst = _RAW_RST_CACHE[text]
     else:
-        # Convert from CommonMark to ReStructured Text.
-        answer = (
-            pypandoc.convert_text(
+        # Slow Path: Missed by batch or new string.
+        # TRY PYTHON CONVERT FIRST.
+        # This prevents the 'Slow Path' from actually being slow.
+        fast_result = _aggressive_fast_convert(text)
+
+        if fast_result is not None:
+            raw_rst = fast_result.strip()
+        else:
+            # The absolute last resort: Shell out to Pandoc
+            raw_rst = pypandoc.convert_text(
                 text,
                 "rst",
                 format=source_format,
-                extra_args=["--columns=%d" % (width - indent)],
-            )
-            .strip()
-            .replace("\n", f"\n{' ' * indent}")
-        )
+                extra_args=["--columns=1000"]
+            ).strip()
+
+        _RAW_RST_CACHE[text] = raw_rst
+
+    # 3. Python Formatting
+    if "::" in raw_rst or ".. code" in raw_rst:
+        answer = raw_rst.replace("\n", f"\n{' ' * indent}")
+    else:
+        answer = wrap(raw_rst, indent=indent, offset=indent, width=width - indent)
+
+    return _finalize(answer, nl, indent)
 
-    # Add a newline to the end of the document if any line breaks are
-    # already present.
-    #
-    # This causes the closing """ to be on the subsequent line only when
-    # appropriate.
+
+def _finalize(answer, nl, indent):
+    """Helper to handle trailing newlines and quotes."""
     if nl or ("\n" in answer and nl is None):
         answer += "\n" + " " * indent
-
-    # If the text ends in a double-quote, append a period.
-    # This ensures that we do not get a parse error when this output is
-    # followed by triple-quotes.
     if answer.endswith('"'):
         answer += "."
-
-    # Done; return the answer.
-    return answer
+    return answer