From c963c4834d0ab05ce8ecf341c74db6ded379fa8a Mon Sep 17 00:00:00 2001
From: Evan Martin <martine@danga.com>
Date: Sun, 12 Aug 2012 15:09:33 -0700
Subject: msvc helper: attempt to filter out when it prints the input filename

This is a heuristic but it appears to work for the Chrome build.
---
 src/msvc_helper-win32.cc | 23 +++++++++++++++++++++++
 src/msvc_helper.h        |  6 ++++++
 src/msvc_helper_test.cc  | 18 ++++++++++++++++++
 3 files changed, 47 insertions(+)

diff --git a/src/msvc_helper-win32.cc b/src/msvc_helper-win32.cc
index ac957e4..f6b2a22 100644
--- a/src/msvc_helper-win32.cc
+++ b/src/msvc_helper-win32.cc
@@ -19,6 +19,16 @@
 
 #include "util.h"
 
+namespace {
+
+/// Return true if \a input ends with \a needle.
+bool EndsWith(const string& input, const string& needle) {
+  return (input.size() >= needle.size() &&
+          input.substr(input.size() - needle.size()) == needle);
+}
+
+}  // anonymous namespace
+
 // static
 string CLWrapper::FilterShowIncludes(const string& line) {
   static const char kMagicPrefix[] = "Note: including file: ";
@@ -35,6 +45,15 @@ string CLWrapper::FilterShowIncludes(const string& line) {
   return "";
 }
 
+// static
+bool CLWrapper::FilterInputFilename(const string& line) {
+  // TODO: other extensions, like .asm?
+  return EndsWith(line, ".c") ||
+      EndsWith(line, ".cc") ||
+      EndsWith(line, ".cxx") ||
+      EndsWith(line, ".cpp");
+}
+
 int CLWrapper::Run(const string& command, string* extra_output) {
   SECURITY_ATTRIBUTES security_attributes = {};
   security_attributes.nLength = sizeof(SECURITY_ATTRIBUTES);
@@ -97,6 +116,10 @@ int CLWrapper::Run(const string& command, string* extra_output) {
       string include = FilterShowIncludes(line);
       if (!include.empty()) {
         includes_.push_back(include);
+      } else if (FilterInputFilename(line)) {
+        // Drop it.
+        // TODO: if we support compiling multiple output files in a single
+        // cl.exe invocation, we should stash the filename.
       } else {
         if (extra_output) {
           extra_output->append(line);
diff --git a/src/msvc_helper.h b/src/msvc_helper.h
index 5a657be..5bf9787 100644
--- a/src/msvc_helper.h
+++ b/src/msvc_helper.h
@@ -34,5 +34,11 @@ struct CLWrapper {
   /// Exposed for testing.
   static string FilterShowIncludes(const string& line);
 
+  /// Parse a line of cl.exe output and return true if it looks like
+  /// it's printing an input filename.  This is a heuristic but it appears
+  /// to be the best we can do.
+  /// Exposed for testing.
+  static bool FilterInputFilename(const string& line);
+
   vector<string> includes_;
 };
diff --git a/src/msvc_helper_test.cc b/src/msvc_helper_test.cc
index 8db4c69..a0bab90 100644
--- a/src/msvc_helper_test.cc
+++ b/src/msvc_helper_test.cc
@@ -31,6 +31,16 @@ TEST(MSVCHelperTest, ShowIncludes) {
                                           "c:\\initspaces.h"));
 }
 
+TEST(MSVCHelperTest, FilterInputFilename) {
+  ASSERT_TRUE(CLWrapper::FilterInputFilename("foobar.cc"));
+  ASSERT_TRUE(CLWrapper::FilterInputFilename("foo bar.cc"));
+  ASSERT_TRUE(CLWrapper::FilterInputFilename("baz.c"));
+
+  ASSERT_FALSE(CLWrapper::FilterInputFilename(
+                   "src\\cl_helper.cc(166) : fatal error C1075: end "
+                   "of file found ..."));
+}
+
 TEST(MSVCHelperTest, Run) {
   CLWrapper cl;
   string output;
@@ -40,3 +50,11 @@ TEST(MSVCHelperTest, Run) {
   ASSERT_EQ(1u, cl.includes_.size());
   ASSERT_EQ("foo.h", cl.includes_[0]);
 }
+
+TEST(MSVCHelperTest, RunFilenameFilter) {
+  CLWrapper cl;
+  string output;
+  cl.Run("cmd /c \"echo foo.cc&& echo cl: warning\"",
+         &output);
+  ASSERT_EQ("cl: warning\n", output);
+}
-- 
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