Absolute path fixes for gn.

tools/gn/label.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "tools/gn/label.h"
 
 #include "base/logging.h"
 #include "tools/gn/err.h"
+#include "tools/gn/filesystem_utils.h"
 #include "tools/gn/parse_tree.h"
 #include "tools/gn/value.h"
 
 namespace {
 
 // We print user visible label names with no trailing slash after the
 // directory name.
 std::string DirWithNoTrailingSlash(const SourceDir& dir) {
   // Be careful not to trim if the input is just "/" or "//".
   if (dir.value().size() > 2)
@@ skipping 67 matching lines @@
              const Label& current_toolchain,
              const Value& original_value,
              const base::StringPiece& input,
              SourceDir* out_dir,
              std::string* out_name,
              SourceDir* out_toolchain_dir,
              std::string* out_toolchain_name,
              Err* err) {
   // To workaround the problem that StringPiece operator[] doesn't return a ref.
   const char* input_str = input.data();
-
-  size_t path_separator = input.find_first_of(":(");
+  size_t offset = 0;
+#if defined(OS_WIN)

[brettw, 2015/01/20 21:05:00]

On Windows, this accepts either "/C:/foo" or "C:/foo" I think. I'm not sure this
condition is correct. I think we should probably prohibit absolute paths that
don't begin in slashes here (the current behavior is to support paths returned
by third party tools, and these normally won't return label names). Can we also
add unit tests for these cases?

+  if (IsPathAbsolute(input)) {
+    // Skip over the drive letter colon.
+    offset = 3;
+  }
+#endif
+  size_t path_separator = input.find_first_of(":(", offset);
   base::StringPiece location_piece;
   base::StringPiece name_piece;
   base::StringPiece toolchain_piece;
   if (path_separator == std::string::npos) {
     location_piece = input;
     // Leave name & toolchain piece null.
   } else {
     location_piece = base::StringPiece(&input_str[0], path_separator);
 
     size_t toolchain_separator = input.find('(', path_separator);
@@ skipping 145 matching lines @@
   }
   return ret;
 }
 
 std::string Label::GetUserVisibleName(const Label& default_toolchain) const {
   bool include_toolchain =
       default_toolchain.dir() != toolchain_dir_ ||
       default_toolchain.name() != toolchain_name_;
   return GetUserVisibleName(include_toolchain);
 }