GN threading refactor

tools/gn/command_desc.cc

Index: tools/gn/command_desc.cc
diff --git a/tools/gn/command_desc.cc b/tools/gn/command_desc.cc
index 415666ca53367e4271e835497d12b4efb64193f8..f680da38ed5abd02c7a8e4c129c9d3b93248ebd1 100644
--- a/tools/gn/command_desc.cc
+++ b/tools/gn/command_desc.cc
@@ -10,8 +10,8 @@
 #include "tools/gn/commands.h"
 #include "tools/gn/config.h"
 #include "tools/gn/config_values_extractors.h"
+#include "tools/gn/filesystem_utils.h"
 #include "tools/gn/item.h"
-#include "tools/gn/item_node.h"
 #include "tools/gn/label.h"
 #include "tools/gn/setup.h"
 #include "tools/gn/standard_out.h"
@@ -21,6 +21,23 @@ namespace commands {
 
 namespace {
 
+// Prints the given directory in a nice way for the user to view.
+std::string FormatSourceDir(const SourceDir& dir) {
+#if defined(OS_WIN)
+  // On Windows we fix up system absolute paths to look like native ones.
+  // Internally, they'll look like "/C:\foo\bar/"
+  if (dir.is_system_absolute()) {
+    std::string buf = dir.value();
+    if (buf.size() > 3 && buf[2] == ':') {
+      buf.erase(buf.begin());  // Erase beginning slash.
+      ConvertPathToSystem(&buf);  // Convert to backslashes.
+      return buf;
+    }
+  }
+#endif
+  return dir.value();
+}
+
 void RecursiveCollectChildDeps(const Target* target, std::set<Label>* result);
 
 void RecursiveCollectDeps(const Target* target, std::set<Label>* result) {
@@ -114,7 +131,7 @@ void PrintLibDirs(const Target* target, bool display_header) {
     OutputString("\nlib_dirs\n");
 
   for (size_t i = 0; i < lib_dirs.size(); i++)
-    OutputString("    " + lib_dirs[i].value() + "\n");
+    OutputString("    " + FormatSourceDir(lib_dirs[i]) + "\n");
 }
 
 void PrintLibs(const Target* target, bool display_header) {
@@ -176,7 +193,7 @@ template<> struct DescValueWriter<SourceFile> {
 };
 template<> struct DescValueWriter<SourceDir> {
   void operator()(const SourceDir& dir, std::ostream& out) const {
-    out << "    " << dir.value() << "\n";
+    out << "    " << FormatSourceDir(dir) << "\n";
   }
 };