Implement target visibility in GN

tools/gn/visibility.h

Index: tools/gn/visibility.h
diff --git a/tools/gn/visibility.h b/tools/gn/visibility.h
new file mode 100644
index 0000000000000000000000000000000000000000..52ec73ca15915811980d464f7d228c57dc671a6e
--- /dev/null
+++ b/tools/gn/visibility.h
@@ -0,0 +1,94 @@
+// Copyright 2014 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_VISIBILITY_H_
+#define TOOLS_GN_VISIBILITY_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/strings/string_piece.h"
+#include "tools/gn/source_dir.h"
+
+class Err;
+class Item;
+class Label;
+class Scope;
+class Value;
+
+class Visibility {
+ public:
+  class VisPattern {
+   public:
+    enum Type {
+      MATCH = 1,  // Exact match for a given target.
+      DIRECTORY,  // Only targets in the file in the given directory.
+      RECURSIVE_DIRECTORY  // The given directory and any subdir.
+                           // (also indicates "public" when dir is empty).
+    };
+
+    VisPattern();
+    VisPattern(Type type, const SourceDir& dir, const base::StringPiece& name);
+    ~VisPattern();
+
+    bool Matches(const Label& label) const;
+
+    Type type() const { return type_; }
+    const SourceDir& dir() const { return dir_; }
+    const std::string& name() const { return name_; }
+
+   private:
+    Type type_;
+
+    // Used when type_ == PRIVATE and PRIVATE_RECURSIVE. This specifies the
+    // directory that to which the pattern is private to.
+    SourceDir dir_;
+
+    // Empty name means match everything. Otherwise the name must match
+    // exactly.
+    std::string name_;
+  };
+
+  // Defaults to private visibility (only the current file).
+  Visibility();
+  ~Visibility();
+
+  // Set the visibility to the thing specified by the given value. On failure,
+  // returns false and sets the error.
+  bool Set(const SourceDir& current_dir, const Value& value, Err* err);
+
+  // Sets the visibility to be public.
+  void SetPublic();
+
+  // Sets the visibility to be private to the given directory.
+  void SetPrivate(const SourceDir& current_dir);
+
+  // Returns true if the target with the given label can depend on one with the
+  // current visibility.
+  bool CanSeeMe(const Label& label) const;
+
+  // Returns a string listing the visibility.
+  std::string Describe() const;
+
+  // Converts the given input string to a pattern. This does special stuff
+  // to treat the pattern as a label. Sets the error on failure.
+  static VisPattern GetPattern(const SourceDir& current_dir,
+                               const Value& value,
+                               Err* err);
+
+  // Helper function to check visibility between the given two items. If
+  // to is invisible to from, returns false and sets the error.
+  static bool CheckItemVisibility(const Item* from, const Item* to, Err* err);
+
+  // Helper function to fill an item's visibility from the "visibility" value
+  // in the current scope.
+  static bool FillItemVisibility(Item* item, Scope* scope, Err* err);
+
+ private:
+  std::vector<VisPattern> patterns_;
+
+  DISALLOW_COPY_AND_ASSIGN(Visibility);
+};
+
+#endif  // TOOLS_GN_VISIBILITY_H_