[libc-commits] [libc] [libc][docs] adds macro handling, POSIX status, and validation to docgen (PR #89421)

[Nick Desaulniers via libc-commits]

================
@@ -9,61 +9,160 @@
 # ==-------------------------------------------------------------------------==#
 from argparse import ArgumentParser, Namespace
 from pathlib import Path
-from typing import Dict
+from typing import Dict, Generator
 import sys
 import json
 
 
-def load_api(hname: str) -> Dict:
-    p = Path(__file__).parent / Path(hname).with_suffix(".json")
-    api = p.read_text(encoding="utf-8")
-    return json.loads(api)
+class DocgenAPIFormatError(Exception):
+    """Raised on fatal formatting errors with a description of a formatting error"""
 
 
-# TODO: we may need to get more sophisticated for less generic implementations.
-# Does libc/src/{hname minus .h suffix}/{fname}.cpp exist?
-def is_implemented(hname: str, fname: str) -> bool:
-    path = Path(
-        Path(__file__).parent.parent.parent,
-        "src",
-        hname.rstrip(".h")
-    )
+class Header:
+    """
+    Maintains implementation information about a standard header file:
+    * where does its implementation dir live
+    * where is its macros file
+    * where is its docgen json file
 
-    if not path.exists():
-        raise FileNotFoundError(f"implementation dir does not exist: {path}")
+    By convention, the macro-only part of a header file is in a header-specific
+    file somewhere in the directory tree with root at
+    ``$LLVM_PROJECT_ROOT/libc/include/llvm-libc-macros``.  Docgen expects that
+    if a macro is implemented, that it appears in a string
+    ``#define MACRO_NAME`` in some ``*-macros.h`` file in the directory tree..
+    Docgen searches for this string in the file to set the implementation status
+    shown in the generated rst docs rendered as html for display at
+    <libc.llvm.org>.
 
-    if not path.is_dir():
-        raise NotADirectoryError(f"implementation dir is not a dir: {path}")
+    By convention, each function for a header is implemented in a function-specific
+    cpp file somewhere in the directory tree with root at, e.g,
+    ``$LLVM_PROJECT_ROOT/libc/src/fenv``. Some headers have architecture-specific
+    implementations, like ``math``, and some don't, like ``fenv``. Docgen uses the
+    presence of this function-specific cpp file to set the implementation status
+    shown in the generated rst docs rendered as html for display at
+    <libc.llvm.org>.
+    """
 
-    # Recursively search for the target source file in the subdirectories under
-    # libc/src/{hname}.
-    for _ in path.glob("**/" + fname + ".cpp"):
-        return True
+    def __init__(self, header_name: str):
+        """
+        :param header_name: e.g., ``"threads.h"`` or ``"signal.h"``
+        """
+        self.name = header_name
+        self.stem = header_name.rstrip(".h")
+        self.libc_root = Path(__file__).parent.parent.parent
+        self.docgen_root = Path(__file__).parent
+        self.docgen_json = self.docgen_root / Path(header_name).with_suffix(".json")
+        self.fns_dir = Path(self.libc_root, "src", self.stem)
+        self.macros_dir = Path(self.libc_root, "include", "llvm-libc-macros")
 
-    return False
+    def macro_file_exists(self) -> bool:
+        for _ in self.__get_macro_files():
+            return True
 
+        return False
 
-def print_functions(header: str, functions: Dict):
-    for key in sorted(functions.keys()):
-        print(f"  * - {key}")
+    def fns_dir_exists(self) -> bool:
----------------
nickdesaulniers wrote:

I don't see the `src` dir going away any time soon.  If this is simply checking for the existence of `libc/src`, consider omitting this check so that we have less code to maintain in docgen.

https://github.com/llvm/llvm-project/pull/89421