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# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at
import buildconfig
import subprocess
import os
import sys
def relativize(path, base=None):
# For absolute path in Unix builds, we need relative paths because
# Windows programs run via Wine don't like these Unix absolute paths
# (they look like command line arguments).
if path.startswith("/"):
return os.path.relpath(path, base)
# For Windows absolute paths, we can just use the unmodified path.
# And if the path starts with '-', it's a command line argument.
if os.path.isabs(path) or path.startswith("-"):
return path
# Remaining case is relative paths, which may be relative to a different
# directory (os.getcwd()) than the needed `base`, so we "rebase" it.
return os.path.relpath(path, base)
def midl(out, input, *flags):
midl = buildconfig.substs["MIDL"]
wine = buildconfig.substs.get("WINE")
base = os.path.dirname( or "."
if midl.lower().endswith(".exe") and wine:
command = [wine, midl]
command = [midl]
command.extend([relativize(f, base) for f in flags])
command.append(relativize(input, base))
print("Executing:", " ".join(command))
result =, cwd=base)
return result.returncode
# midl outputs dlldata to a single dlldata.c file by default. This prevents running
# midl in parallel in the same directory for idl files that would generate dlldata.c
# because of race conditions updating the file. Instead, we ask midl to create
# separate files, and we merge them manually.
def merge_dlldata(out, *inputs):
inputs = [open(i) for i in inputs]
read_a_line = [True] * len(inputs)
while True:
lines = [
f.readline() if read_a_line[n] else lines[n] for n, f in enumerate(inputs)
unique_lines = set(lines)
if len(unique_lines) == 1:
# All the lines are identical
if not lines[0]:
read_a_line = [True] * len(inputs)
elif (
len(unique_lines) == 2
and len([l for l in unique_lines if "#define" in l]) == 1
# Most lines are identical. When they aren't, it's typically because some
# files have an extra #define that others don't. When that happens, we
# print out the #define, and get a new input line from the files that had
# a #define on the next iteration. We expect that next line to match what
# the other files had on this iteration.
# Note: we explicitly don't support the case where there are different
# defines across different files, except when there's a different one
# for each file, in which case it's handled further below.
a = unique_lines.pop()
if "#define" in a:
read_a_line = ["#define" in l for l in lines]
elif len(unique_lines) != len(lines):
# If for some reason, we don't get lines that are entirely different
# from each other, we have some unexpected input.
"Error while merging dlldata. Last lines read: {}".format(lines),
return 1
for line in lines:
read_a_line = [True] * len(inputs)
return 0