common/scripts: add script to generate distfiles from meson wrap files

useful for mesa, where there are a signficant number of crates
referenced via meson wrap files, but this could be generally useful for
other meson-based packages that do a similar thing for vendored
libraries.

This could be further extended in the future to add support for
git/hg/svn wraps by adding subclasses of `Wrap` that support those
metadata options.

setting `MESON_PACKAGE_CACHE_DIR` allows meson to look for tarballs for
wraps it needs automatically.

Author: classabbyamp

Manual.md

@@ -1107,7 +1107,10 @@ additional paths to be searched when linking target binaries to be introspected.
 - `meson` creates a cross file, `${XBPS_WRAPPERDIR}/meson/xbps_meson.cross`, which configures
 meson for cross builds. This is particularly useful for building packages that wrap meson
 invocations (e.g., `python3-pep517` packages that use a meson backend) and is added by default
-for packages that use the `meson` build style.
+for packages that use the `meson` build style. It also sets `$MESON_PACKAGE_CACHE_DIR` to
+`$XBPS_SRCDISTDIR/$pkgname-$version/` so libraries specified as meson wraps can be added to
+distfiles and will be automatically used by meson. See also `common/scripts/gen-wrap-distfiles.py`
+for a script that generates distfiles entries for wraps.
 
 - `numpy` configures the environment for cross-compilation of python packages that provide
 compiled extensions linking to NumPy C libraries. If the `meson` build helper is also

common/build-helper/meson.sh

@@ -1,6 +1,9 @@
 # This build helper writes a Meson cross-file, allowing other build styles
 # to properly drive cross-builds in Meson when appropriate
 
+# allows meson to automatically unpack wrapped dependencies specified in distfiles
+export MESON_PACKAGE_CACHE_DIR="${XBPS_SRCDISTDIR}/${pkgname}-${version}/"
+
 # Action is only taken for cross builds
 [ -z "$CROSS_BUILD" ] && return 0
 

common/scripts/gen-wrap-distfiles.py

@@ -0,0 +1,120 @@
+#!/usr/bin/python3
+
+import sys
+from abc import ABC, abstractmethod
+from configparser import ConfigParser
+from dataclasses import dataclass
+from pathlib import Path
+
+@dataclass
+class Wrap(ABC):
+	src_path: Path
+
+	directory: str | None = None
+	patch_url: str | None = None
+	patch_fallback_url: str | None = None
+	patch_filename: str | None = None
+	patch_hash: str | None = None
+	patch_directory: str | None = None
+	diff_files: str | None = None
+	method: str | None = None
+
+	@property
+	@abstractmethod
+	def distfile(self):
+		raise NotImplementedError
+
+	@property
+	@abstractmethod
+	def checksum(self):
+		raise NotImplementedError
+
+	@property
+	@abstractmethod
+	def filename(self):
+		raise NotImplementedError
+
+
+@dataclass
+class WrapFile(Wrap):
+	source_url: str | None = None
+	source_fallback_url: str | None = None
+	source_filename: str | None = None
+	source_hash: str | None = None
+	lead_directory_missing: str | None = None
+
+	@property
+	def distfile(self):
+		if self.source_url:
+			return f"{self.source_url}>{self.filename}"
+		raise ValueError(f"missing source_url in wrap {self.src_path}")
+
+	@property
+	def checksum(self):
+		if self.source_hash:
+			return self.source_hash
+		raise ValueError(f"missing source_hash in wrap {self.src_path}")
+
+	@property
+	def filename(self):
+		if self.source_filename:
+			return self.source_filename
+		raise ValueError(f"missing source_filename in wrap {self.src_path}")
+
+
+def read_wrap(p: Path) -> Wrap:
+	wrap = ConfigParser()
+	with p.open() as f:
+		wrap.read_file(f)
+
+	for sec in wrap.sections():
+		if sec.startswith("wrap-"):
+			break
+	else:
+		raise ValueError(f"missing 'wrap-*' section in wrap {p}")
+
+	match sec:
+		case "wrap-file":
+			cls = WrapFile
+		case "wrap-git":
+			raise NotImplementedError
+		case "wrap-hg":
+			raise NotImplementedError
+		case "wrap-svn":
+			raise NotImplementedError
+		case _:
+			raise NotImplementedError
+
+	return cls(src_path=p, **dict(wrap.items(sec)))
+
+
+def print_list(var: str, contents: list[str]):
+	print(f"""{var}+="
+ {"\n ".join(contents)}
+\"""")
+
+
+if __name__ == "__main__":
+	distfiles = []
+	checksums = []
+	skip_extracts = []
+
+	if len(sys.argv[1:]) < 1:
+		print(f"usage: {sys.argv[0]} <wrap files...>")
+		exit()
+
+	for arg in sys.argv[1:]:
+		wrap_path = Path(arg)
+		if wrap_path.is_file():
+			try:
+				wrap = read_wrap(wrap_path)
+
+				distfiles.append(wrap.distfile)
+				checksums.append(wrap.checksum)
+				skip_extracts.append(wrap.filename)
+			except ValueError as e:
+				print("=> ERROR:", e, file=sys.stderr)
+
+	print_list("distfiles", distfiles)
+	print_list("checksum", checksums)
+	print_list("skip_extraction", skip_extracts)