GN: Manually search path for Python
This manually searches the path for python rather than executing "cmd" to find it. This saves about 80ms in run time.
Review URL: https://codereview.chromium.org/1462393003
Cr-Original-Commit-Position: refs/heads/master@{#360981}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 30069efcdbf27248a74fcdcf59e4c08df1d75765
diff --git a/tools/gn/setup.cc b/tools/gn/setup.cc
index 033dab4..87339ca 100644
--- a/tools/gn/setup.cc
+++ b/tools/gn/setup.cc
@@ -148,6 +148,42 @@
g_scheduler->DecrementWorkCount();
}
+#if defined(OS_WIN)
+const base::char16 kPythonExeName[] = L"python.exe";
+
+base::FilePath FindWindowsPython() {
+ base::char16 current_directory[MAX_PATH];
+ ::GetCurrentDirectory(MAX_PATH, current_directory);
+
+ // First search for python.exe in the current directory.
+ base::FilePath cur_dir_candidate_exe =
+ base::FilePath(current_directory).Append(kPythonExeName);
+ if (base::PathExists(cur_dir_candidate_exe))
+ return cur_dir_candidate_exe;
+
+ // Get the path.
+ const base::char16 kPathEnvVarName[] = L"Path";
+ DWORD path_length = ::GetEnvironmentVariable(kPathEnvVarName, nullptr, 0);
+ if (path_length == 0)
+ return base::FilePath();
+ scoped_ptr<base::char16[]> full_path(new base::char16[path_length]);
+ DWORD actual_path_length =
+ ::GetEnvironmentVariable(kPathEnvVarName, full_path.get(), path_length);
+ CHECK_EQ(path_length, actual_path_length + 1);
+
+ // Search for python.exe in the path.
+ for (const auto& component : base::SplitStringPiece(
+ base::StringPiece16(full_path.get(), path_length), L";",
+ base::TRIM_WHITESPACE, base::SPLIT_WANT_NONEMPTY)) {
+ base::FilePath candidate_exe =
+ base::FilePath(component).Append(kPythonExeName);
+ if (base::PathExists(candidate_exe))
+ return candidate_exe;
+ }
+ return base::FilePath();
+}
+#endif
+
} // namespace
const char Setup::kBuildArgFileName[] = "args.gn";
@@ -478,21 +514,13 @@
// Trace this since it tends to be a bit slow on Windows.
ScopedTrace setup_trace(TraceItem::TRACE_SETUP, "Fill Python Path");
#if defined(OS_WIN)
- // Find Python on the path so we can use the absolute path in the build.
- const base::char16 kGetPython[] =
- L"cmd.exe /c python -c \"import sys; print sys.executable\"";
- std::string python_path;
- if (base::GetAppOutput(kGetPython, &python_path)) {
- base::TrimWhitespaceASCII(python_path, base::TRIM_ALL, &python_path);
- if (scheduler_.verbose_logging())
- scheduler_.Log("Found python", python_path);
- } else {
+ base::FilePath python_path = FindWindowsPython();
+ if (python_path.empty()) {
scheduler_.Log("WARNING", "Could not find python on path, using "
"just \"python.exe\"");
- python_path = "python.exe";
+ python_path = base::FilePath(kPythonExeName);
}
- build_settings_.set_python_path(base::FilePath(base::UTF8ToUTF16(python_path))
- .NormalizePathSeparatorsTo('/'));
+ build_settings_.set_python_path(python_path.NormalizePathSeparatorsTo('/'));
#else
build_settings_.set_python_path(base::FilePath("python"));
#endif
