1 files changed, 126 insertions, 0 deletions
diff --git a/gn/tools/gn/label.h b/gn/tools/gn/label.h
new file mode 100644
index 00000000000..3c3d85a4802
--- /dev/null
+++ b/gn/tools/gn/label.h
@@ -0,0 +1,126 @@
+// 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_LABEL_H_
+#define TOOLS_GN_LABEL_H_
+
+#include <stddef.h>
+
+#include "tools/gn/source_dir.h"
+
+class Err;
+class Value;
+
+// A label represents the name of a target or some other named thing in
+// the source path. The label is always absolute and always includes a name
+// part, so it starts with a slash, and has one colon.
+class Label {
+ public:
+  Label();
+
+  // Makes a label given an already-separated out path and name.
+  // See also Resolve().
+  Label(const SourceDir& dir,
+        const base::StringPiece& name,
+        const SourceDir& toolchain_dir,
+        const base::StringPiece& toolchain_name);
+
+  // Makes a label with an empty toolchain.
+  Label(const SourceDir& dir, const base::StringPiece& name);
+  Label(const Label& other);
+  ~Label();
+
+  // Resolves a string from a build file that may be relative to the
+  // current directory into a fully qualified label. On failure returns an
+  // is_null() label and sets the error.
+  static Label Resolve(const SourceDir& current_dir,
+                       const Label& current_toolchain,
+                       const Value& input,
+                       Err* err);
+
+  bool is_null() const { return dir_.is_null(); }
+
+  const SourceDir& dir() const { return dir_; }
+  const std::string& name() const { return name_; }
+
+  const SourceDir& toolchain_dir() const { return toolchain_dir_; }
+  const std::string& toolchain_name() const { return toolchain_name_; }
+
+  // Returns the current label's toolchain as its own Label.
+  Label GetToolchainLabel() const;
+
+  // Returns a copy of this label but with an empty toolchain.
+  Label GetWithNoToolchain() const;
+
+  // Formats this label in a way that we can present to the user or expose to
+  // other parts of the system. SourceDirs end in slashes, but the user
+  // expects names like "//chrome/renderer:renderer_config" when printed. The
+  // toolchain is optionally included.
+  std::string GetUserVisibleName(bool include_toolchain) const;
+
+  // Like the above version, but automatically includes the toolchain if it's
+  // not the default one. Normally the user only cares about the toolchain for
+  // non-default ones, so this can make certain output more clear.
+  std::string GetUserVisibleName(const Label& default_toolchain) const;
+
+  bool operator==(const Label& other) const {
+    return name_ == other.name_ && dir_ == other.dir_ &&
+           toolchain_dir_ == other.toolchain_dir_ &&
+           toolchain_name_ == other.toolchain_name_;
+  }
+  bool operator!=(const Label& other) const { return !operator==(other); }
+  bool operator<(const Label& other) const {
+    if (int c = dir_.value().compare(other.dir_.value()))
+      return c < 0;
+    if (int c = name_.compare(other.name_))
+      return c < 0;
+    if (int c = toolchain_dir_.value().compare(other.toolchain_dir_.value()))
+      return c < 0;
+    return toolchain_name_ < other.toolchain_name_;
+  }
+
+  void swap(Label& other) {
+    dir_.swap(other.dir_);
+    name_.swap(other.name_);
+    toolchain_dir_.swap(other.toolchain_dir_);
+    toolchain_name_.swap(other.toolchain_name_);
+  }
+
+  // Returns true if the toolchain dir/name of this object matches some
+  // other object.
+  bool ToolchainsEqual(const Label& other) const {
+    return toolchain_dir_ == other.toolchain_dir_ &&
+           toolchain_name_ == other.toolchain_name_;
+  }
+
+ private:
+  SourceDir dir_;
+  std::string name_;
+
+  SourceDir toolchain_dir_;
+  std::string toolchain_name_;
+};
+
+namespace std {
+
+template <>
+struct hash<Label> {
+  std::size_t operator()(const Label& v) const {
+    hash<std::string> stringhash;
+    return ((stringhash(v.dir().value()) * 131 + stringhash(v.name())) * 131 +
+            stringhash(v.toolchain_dir().value())) *
+               131 +
+           stringhash(v.toolchain_name());
+  }
+};
+
+}  // namespace std
+
+inline void swap(Label& lhs, Label& rhs) {
+  lhs.swap(rhs);
+}
+
+extern const char kLabels_Help[];
+
+#endif  // TOOLS_GN_LABEL_H_