build/midl.py

   1 # This Source Code Form is subject to the terms of the Mozilla Public
   2 # License, v. 2.0. If a copy of the MPL was not distributed with this
   3 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
   4
   5 import buildconfig
   6 import subprocess
   7 import os
   8 import sys
   9
  10
  11 def relativize(path, base=None):
  12     # For absolute path in Unix builds, we need relative paths because
  13     # Windows programs run via Wine don't like these Unix absolute paths
  14     # (they look like command line arguments).
  15     if path.startswith("/"):
  16         return os.path.relpath(path, base)
  17     # For Windows absolute paths, we can just use the unmodified path.
  18     # And if the path starts with '-', it's a command line argument.
  19     if os.path.isabs(path) or path.startswith("-"):
  20         return path
  21     # Remaining case is relative paths, which may be relative to a different
  22     # directory (os.getcwd()) than the needed `base`, so we "rebase" it.
  23     return os.path.relpath(path, base)
  24
  25
  26 def midl(out, input, *flags):
  27     out.avoid_writing_to_file()
  28     midl = buildconfig.substs["MIDL"]
  29     wine = buildconfig.substs.get("WINE")
  30     base = os.path.dirname(out.name) or "."
  31     if midl.lower().endswith(".exe") and wine:
  32         command = [wine, midl]
  33     else:
  34         command = [midl]
  35     command.extend(buildconfig.substs["MIDL_FLAGS"])
  36     command.extend([relativize(f, base) for f in flags])
  37     command.append("-Oicf")
  38     command.append(relativize(input, base))
  39     print("Executing:", " ".join(command))
  40     result = subprocess.run(command, cwd=base)
  41     return result.returncode
  42
  43
  44 # midl outputs dlldata to a single dlldata.c file by default. This prevents running
  45 # midl in parallel in the same directory for idl files that would generate dlldata.c
  46 # because of race conditions updating the file. Instead, we ask midl to create
  47 # separate files, and we merge them manually.
  48 def merge_dlldata(out, *inputs):
  49     inputs = [open(i) for i in inputs]
  50     read_a_line = [True] * len(inputs)
  51     while True:
  52         lines = [
  53             f.readline() if read_a_line[n] else lines[n] for n, f in enumerate(inputs)
  54         ]
  55         unique_lines = set(lines)
  56         if len(unique_lines) == 1:
  57             # All the lines are identical
  58             if not lines[0]:
  59                 break
  60             out.write(lines[0])
  61             read_a_line = [True] * len(inputs)
  62         elif (
  63             len(unique_lines) == 2
  64             and len([l for l in unique_lines if "#define" in l]) == 1
  65         ):
  66             # Most lines are identical. When they aren't, it's typically because some
  67             # files have an extra #define that others don't. When that happens, we
  68             # print out the #define, and get a new input line from the files that had
  69             # a #define on the next iteration. We expect that next line to match what
  70             # the other files had on this iteration.
  71             # Note: we explicitly don't support the case where there are different
  72             # defines across different files, except when there's a different one
  73             # for each file, in which case it's handled further below.
  74             a = unique_lines.pop()
  75             if "#define" in a:
  76                 out.write(a)
  77             else:
  78                 out.write(unique_lines.pop())
  79             read_a_line = ["#define" in l for l in lines]
  80         elif len(unique_lines) != len(lines):
  81             # If for some reason, we don't get lines that are entirely different
  82             # from each other, we have some unexpected input.
  83             print(
  84                 "Error while merging dlldata. Last lines read: {}".format(lines),
  85                 file=sys.stderr,
  86             )
  87             return 1
  88         else:
  89             for line in lines:
  90                 out.write(line)
  91             read_a_line = [True] * len(inputs)
  92
  93     return 0