[vlc-devel] [PATCH v2] contrib: Workaround for absolute paths in pc files

[Marvin Scholz]

Meson generates pc files with absolute paths to static libraries, while
this is completely fine, libtool can not deal with this and produces
broken build results in that case.
---
 contrib/src/libplacebo/rules.mak    |   3 +
 contrib/src/pkg-rewrite-absolute.py | 141 ++++++++++++++++++++++++++++
 2 files changed, 144 insertions(+)
 create mode 100755 contrib/src/pkg-rewrite-absolute.py

diff --git a/contrib/src/libplacebo/rules.mak b/contrib/src/libplacebo/rules.mak
index 9d4295e72c..1f34691824 100644
--- a/contrib/src/libplacebo/rules.mak
+++ b/contrib/src/libplacebo/rules.mak
@@ -36,4 +36,7 @@ libplacebo: $(PLACEBO_ARCHIVE) .sum-libplacebo
 	cd $< && cd build && ninja install
 # Work-around messon issue https://github.com/mesonbuild/meson/issues/4091
 	sed -i.orig -e 's/Libs: \(.*\) -L$${libdir} -lplacebo/Libs: -L$${libdir} -lplacebo \1/g' $(PREFIX)/lib/pkgconfig/libplacebo.pc
+# Work-around for full paths to static libraries, which libtool does not like
+# See https://github.com/mesonbuild/meson/issues/5479
+	(cd $(UNPACK_DIR) && $(SRC_BUILT)/pkg-rewrite-absolute.py -i "$(PREFIX)/lib/pkgconfig/libplacebo.pc")
 	touch $@
diff --git a/contrib/src/pkg-rewrite-absolute.py b/contrib/src/pkg-rewrite-absolute.py
new file mode 100755
index 0000000000..7cab6c89d4
--- /dev/null
+++ b/contrib/src/pkg-rewrite-absolute.py
@@ -0,0 +1,141 @@
+#!/usr/bin/env python3
+import os, sys, argparse
+
+class PkgConfigFile():
+    """Representation of a pkg-config file (.pc)"""
+
+    pc_variables = {}
+    pc_variables_expanded = {}
+
+    pc_keywords = {}
+
+    def __init__(self, file):
+        for line in file:
+            self.parse_pc_line(line)
+
+    def parse_pc_line(self, line):
+        for i, c in enumerate(line):
+            if c is '=':
+                # This is a pkg-config variable line
+                key = line[:i].strip()
+                val = line[(i + 1):].strip()
+
+                # Add unexpanded version of variable
+                self.pc_variables.update({ key : val })
+
+                # Add expanded version of variable
+                self.pc_variables_expanded.update({ key : self.expand_pc_vars(val) })
+            elif c is ':':
+                # This is a pkg-config keyword line
+                key = line[:i].strip()
+                val = line[(i + 1):].strip()
+
+                self.pc_keywords.update({ key : val })
+
+    def expand_pc_vars(self, line):
+        for key, val in self.pc_variables_expanded.items():
+            line = line.replace('${' + key + '}', val)
+        return line
+
+    def get_variable(self, key, expand=True):
+        if expand:
+            return self.pc_variables_expanded.get(key, None)
+        else:
+            return self.pc_variables.get(key, None)
+
+    def get_keyword(self, key, expand=True):
+        keyword = self.pc_keywords.get(key, None)
+        if expand and keyword != None:
+            return self.expand_pc_vars(keyword)
+        else:
+            return keyword
+
+    def set_keyword(self, key, value):
+        self.pc_keywords.update({ key : value })
+
+    def write(self, file):
+        pc_contents = ''
+        # Print variables
+        for key, val in self.pc_variables.items():
+            pc_contents += key + '=' + val + '\n'
+        pc_contents += '\n'
+        # Print keywords
+        for key, val in self.pc_keywords.items():
+            pc_contents += key + ': ' + val + '\n'
+
+        file.write(pc_contents)
+
+def remove_str_fix(text, prefix, suffix):
+    start = len(prefix) if text.startswith(prefix) else 0
+    end_offset = len(suffix) if text.endswith(suffix) else 0
+    end = len(text) - end_offset
+    return text[start:end]
+
+def rewrite_abs_to_rel(pc_file):
+    linker_args = pc_file.get_keyword('Libs', expand=False)
+    if linker_args is None:
+        raise KeyError('No "Libs" keyword in input .pc file found!')
+    linker_args_list = linker_args.split()
+
+    # Replace absolute library paths with relative ones
+    # i.e. /foo/bar/baz.a to -L/foo/bar -lbaz
+    lib_paths = []
+    out_args = []
+    for arg in linker_args_list:
+        if arg.startswith('-L'):
+            path = arg[2:]
+            path = pc_file.expand_pc_vars(path)
+            lib_paths.append(path)
+
+        # Filter all absolute static library paths
+        if arg.startswith('/') and arg.endswith('.a'):
+            lib_path = os.path.dirname(arg)
+            lib_filename = os.path.basename(arg)
+            # Remove lib prefix and .a suffix
+            lib_name = remove_str_fix(lib_filename, 'lib', '.a')
+            if lib_path not in lib_paths:
+                out_args.append('-L' + lib_path)
+                lib_paths.append(lib_path)
+            out_args.append('-l' + lib_name)
+        else:
+            out_args.append(arg)
+
+    linker_args = ' '.join(out_args)
+    pc_file.set_keyword('Libs', linker_args)
+
+# Main function
+# Do argument parsing and other stuff needed
+# for CLI usage here.
+def main():
+    if not sys.version_info >= (3, 4):
+        print("Python version 3.4 or higher required!", file=sys.stderr)
+        exit(1)
+
+    # Create main parser
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-i', '--input', required=True)
+    parser.add_argument('-o', '--output')
+
+    args = parser.parse_args()
+
+    # Default to input file (in-place editing) if no output file is given
+    args.output = args.output or args.input
+
+    # Read .pc from input file
+    input_file = sys.stdin if args.input is '-' else open(args.input, 'r')
+    pc_file = PkgConfigFile(input_file)
+    if input_file is not sys.stdin:
+        input_file.close()
+
+    rewrite_abs_to_rel(pc_file)
+
+    # Write output
+    output_file = sys.stdout if args.output is '-' else open(args.output, 'w')
+    pc_file.write(output_file)
+    if output_file is not sys.stdout:
+        output_file.close()
+
+    return 0
+
+if __name__ == "__main__":
+    exit(main())
-- 
2.21.0 (Apple Git-122)