GN generator for GYP actions

tools/gn/filesystem_utils.h

Index: tools/gn/filesystem_utils.h
diff --git a/tools/gn/filesystem_utils.h b/tools/gn/filesystem_utils.h
index 9899cae4eacfdcc22612a2e06f360ea3fec06c42..152851d971cc4a1e167254eae66ae38a76f9842b 100644
--- a/tools/gn/filesystem_utils.h
+++ b/tools/gn/filesystem_utils.h
@@ -138,4 +138,25 @@ std::string PathToSystem(const std::string& path);
 std::string RebaseSourceAbsolutePath(const std::string& input,
                                      const SourceDir& dest_dir);
 
+// Returns the given directory with no terminating slash at the end, such that
+// appending a slash and more stuff will produce a valid path.
+//
+// If the directory refers to either the source or system root, we'll append
+// a "." so this remains valid.
+std::string DirectoryWithNoLastSlash(const SourceDir& dir);
+
+// -----------------------------------------------------------------------------
+
+// These functions return the various flavors of output and gen directories.
+SourceDir GetToolchainOutputDir(const Settings* settings);
+SourceDir GetToolchainGenDir(const Settings* settings);
+SourceDir GetOutputDirForSourceDir(const Settings* settings,
+                                   const SourceDir& source_dir);
+SourceDir GetGenDirForSourceDir(const Settings* settings,
+                                const SourceDir& source_dir);
+SourceDir GetTargetOutputDir(const Target* target);
+SourceDir GetTargetGenDir(const Target* target);
+SourceDir GetCurrentOutputDir(const Scope* scope);
+SourceDir GetCurrentGenDir(const Scope* scope);
+
 #endif  // TOOLS_GN_FILESYSTEM_UTILS_H_