Add initial prototype for the GN meta-buildsystem.

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
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+// 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.
+
+#ifndef TOOLS_GN_FILESYSTEM_UTILS_H_
+#define TOOLS_GN_FILESYSTEM_UTILS_H_
+
+#include <string>
+
+#include "base/files/file_path.h"
+#include "base/strings/string_piece.h"
+#include "tools/gn/settings.h"
+#include "tools/gn/target.h"
+
+class Err;
+class Location;
+class Value;
+
+enum SourceFileType {
+  SOURCE_UNKNOWN,
+  SOURCE_ASM,
+  SOURCE_C,
+  SOURCE_CC,
+  SOURCE_H,
+  SOURCE_M,
+  SOURCE_MM,
+  //SOURCE_S,  // TODO(brettw) what is this?
+  SOURCE_RC,
+};
+
+SourceFileType GetSourceFileType(const SourceFile& file,
+                                 Settings::TargetOS os);
+
+// Returns the extension, not including the dot, for the given file type on the
+// given system.
+//
+// Some targets make multiple files (like a .dll and an import library). This
+// function returns the name of the file other targets should depend on and
+// link to (so in this example, the import library).
+const char* GetExtensionForOutputType(Target::OutputType type,
+                                      Settings::TargetOS os);
+
+std::string FilePathToUTF8(const base::FilePath& path);
+base::FilePath UTF8ToFilePath(const base::StringPiece& sp);
+
+// Extensions -----------------------------------------------------------------
+
+// Returns the index of the extension (character after the last dot not after a
+// slash). Returns std::string::npos if not found. Returns path.size() if the
+// file ends with a dot.
+size_t FindExtensionOffset(const std::string& path);
+
+// Returns a string piece pointing into the input string identifying the
+// extension. Note that the input pointer must outlive the output.
+base::StringPiece FindExtension(const std::string* path);
+
+// Filename parts -------------------------------------------------------------
+
+// Returns the offset of the character following the last slash, or
+// 0 if no slash was found. Returns path.size() if the path ends with a slash.
+// Note that the input pointer must outlive the output.
+size_t FindFilenameOffset(const std::string& path);
+
+// Returns a string piece pointing into the input string identifying the
+// file name (following the last slash, including the extension). Note that the
+// input pointer must outlive the output.
+base::StringPiece FindFilename(const std::string* path);
+
+// Like FindFilename but does not include the extension.
+base::StringPiece FindFilenameNoExtension(const std::string* path);
+
+// Removes everything after the last slash. The last slash, if any, will be
+// preserved.
+void RemoveFilename(std::string* path);
+
+// Returns true if the given path ends with a slash.
+bool EndsWithSlash(const std::string& s);
+
+// Path parts -----------------------------------------------------------------
+
+// Returns a string piece pointing into the input string identifying the
+// directory name of the given path, including the last slash. Note that the
+// input pointer must outlive the output.
+base::StringPiece FindDir(const std::string* path);
+
+// Verifies that the given string references a file inside of the given
+// directory. This is pretty stupid and doesn't handle "." and "..", etc.,
+// it is designed for a sanity check to keep people from writing output files
+// to the source directory accidentally.
+//
+// The originating value will be blamed in the error.
+//
+// If the file isn't in the dir, returns false and sets the error. Otherwise
+// returns true and leaves the error untouched.
+bool EnsureStringIsInOutputDir(const SourceDir& dir,
+                               const std::string& str,
+                               const Value& originating,
+                               Err* err);
+
+// ----------------------------------------------------------------------------
+
+// Converts a directory to its inverse (e.g. "/foo/bar/" -> "../../").
+// This will be the empty string for the root directories ("/" and "//"), and
+// in all other cases, this is guaranteed to end in a slash.
+std::string InvertDir(const SourceDir& dir);
+
+// Collapses "." and sequential "/"s and evaluates "..".
+void NormalizePath(std::string* path);
+
+// Converts slashes to backslashes for Windows. Keeps the string unchanged
+// for other systems.
+void ConvertPathToSystem(std::string* path);
+std::string PathToSystem(const std::string& path);
+
+#endif  // TOOLS_GN_FILESYSTEM_UTILS_H_