msvc helper: drop system includes

Drop any #includes that look like they're referencing system headers.
This reduces the dependency information considerably.

3 files changed, 30 insertions, 3 deletions

diff --git a/src/msvc_helper-win32.cc b/src/msvc_helper-win32.cc
index f6b2a22..624bc2d 100644
--- a/src/msvc_helper-win32.cc
+++ b/src/msvc_helper-win32.cc
@@ -17,6 +17,7 @@
 #include <string.h>
 #include <windows.h>
 
+#include "includes_normalize.h"
 #include "util.h"
 
 namespace {
@@ -46,6 +47,13 @@ string CLWrapper::FilterShowIncludes(const string& line) {
 }
 
 // static
+bool CLWrapper::IsSystemInclude(const string& path) {
+  // TODO: this is a heuristic, perhaps there's a better way?
+  return (path.find("program files") != string::npos ||
+          path.find("microsoft visual studio") != string::npos);
+}
+
+// static
 bool CLWrapper::FilterInputFilename(const string& line) {
   // TODO: other extensions, like .asm?
   return EndsWith(line, ".c") ||
@@ -115,7 +123,9 @@ int CLWrapper::Run(const string& command, string* extra_output) {
 
       string include = FilterShowIncludes(line);
       if (!include.empty()) {
-        includes_.push_back(include);
+        include = IncludesNormalize::Normalize(include, NULL);
+        if (!IsSystemInclude(include))
+          includes_.push_back(include);
       } else if (FilterInputFilename(line)) {
         // Drop it.
         // TODO: if we support compiling multiple output files in a single
diff --git a/src/msvc_helper.h b/src/msvc_helper.h
index 5bf9787..41b9f9b 100644
--- a/src/msvc_helper.h
+++ b/src/msvc_helper.h
@@ -16,8 +16,6 @@
 #include <vector>
 using namespace std;
 
-struct StringPiece;
-
 /// Visual Studio's cl.exe requires some massaging to work with Ninja;
 /// for example, it emits include information on stderr in a funny
 /// format when building with /showIncludes.  This class wraps a CL
@@ -34,6 +32,11 @@ struct CLWrapper {
   /// Exposed for testing.
   static string FilterShowIncludes(const string& line);
 
+  /// Return true if a mentioned include file is a system path.
+  /// Expects the path to already by normalized (including lower case).
+  /// Filtering these out reduces dependency information considerably.
+  static bool IsSystemInclude(const string& path);
+
   /// 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.
diff --git a/src/msvc_helper_test.cc b/src/msvc_helper_test.cc
index a0bab90..b65d66f 100644
--- a/src/msvc_helper_test.cc
+++ b/src/msvc_helper_test.cc
@@ -58,3 +58,17 @@ TEST(MSVCHelperTest, RunFilenameFilter) {
          &output);
   ASSERT_EQ("cl: warning\n", output);
 }
+
+TEST(MSVCHelperTest, RunSystemInclude) {
+  CLWrapper cl;
+  string output;
+  cl.Run("cmd /c \"echo Note: including file: c:\\Program Files\\foo.h&&"
+         "echo Note: including file: d:\\Microsoft Visual Studio\\bar.h&&"
+         "echo Note: including file: path.h\"",
+         &output);
+  // We should have dropped the first two includes because they look like
+  // system headers.
+  ASSERT_EQ("", output);
+  ASSERT_EQ(1u, cl.includes_.size());
+  ASSERT_EQ("path.h", cl.includes_[0]);
+}