Add initial prototype for the GN meta-buildsystem.

tools/gn/escape.cc

Index: tools/gn/escape.cc
diff --git a/tools/gn/escape.cc b/tools/gn/escape.cc
new file mode 100644
index 0000000000000000000000000000000000000000..5fc7b6f6a837bd489629206bec2330af11d09278
--- /dev/null
+++ b/tools/gn/escape.cc
@@ -0,0 +1,77 @@
+// 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/escape.h"
+
+#include "base/containers/stack_container.h"
+
+namespace {
+
+template<typename DestString>
+void EscapeStringToString(const base::StringPiece& str,
+                          const EscapeOptions& options,
+                          DestString* dest) {
+  bool used_quotes = false;
+
+  for (size_t i = 0; i < str.size(); i++) {
+    if (str[i] == '$' && options.mode == ESCAPE_NINJA) {
+      // Escape dollars signs since ninja treats these specially.
+      dest->push_back('$');
+      dest->push_back('$');
+    } else if (str[i] == '"' && options.mode == ESCAPE_SHELL) {
+      // Escape quotes with backslashes for the command-line (Ninja doesn't
+      // care).
+      dest->push_back('\\');
+      dest->push_back('"');
+    } else if (str[i] == ' ') {
+      if (options.mode == ESCAPE_NINJA) {
+        // For ninja just escape spaces with $.
+        dest->push_back('$');
+      } else if (options.mode == ESCAPE_SHELL && !options.inhibit_quoting) {
+        // For the shell, quote the whole string.
+        if (!used_quotes) {
+          used_quotes = true;
+          dest->insert(dest->begin(), '"');
+        }
+      }
+      dest->push_back(' ');
+#if defined(OS_WIN)
+    } else if (str[i] == '/' && options.convert_slashes) {
+      // Convert slashes on Windows if requested.
+      dest->push_back('\\');
+#else
+    } else if (str[i] == '\\' && options.mode == ESCAPE_SHELL) {
+      // For non-Windows shell, escape backslashes.
+      dest->push_back('\\');
+      dest->push_back('\\');
+#endif
+    } else {
+      dest->push_back(str[i]);
+    }
+  }
+
+  if (used_quotes)
+    dest->push_back('"');
+}
+
+}  // namespace
+
+std::string EscapeString(const base::StringPiece& str,
+                         const EscapeOptions& options) {
+  std::string result;
+  result.reserve(str.size() + 4);  // Guess we'll add a couple of extra chars.
+  EscapeStringToString(str, options, &result);
+  return result;
+}
+
+void EscapeStringToStream(std::ostream& out,
+                          const base::StringPiece& str,
+                          const EscapeOptions& options) {
+  // Escape to a stack buffer and then write out to the stream.
+  base::StackVector<char, 256> result;
+  result->reserve(str.size() + 4);  // Guess we'll add a couple of extra chars.
+  EscapeStringToString(str, options, &result.container());
+  if (!result->empty())
+    out.write(result->data(), result->size());
+}