Implement declarativeContent API.

chrome/browser/extensions/api/declarative_content/content_condition.h

+// Copyright (c) 2012 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 CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_CONTENT_CONTENT_CONDITION_H_
+#define CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_CONTENT_CONTENT_CONDITION_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/hash_tables.h"
+#include "base/memory/linked_ptr.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/scoped_vector.h"
+#include "base/values.h"
+#include "chrome/browser/extensions/api/declarative/declarative_rule.h"
+#include "chrome/common/extensions/matcher/url_matcher.h"
+#include "googleurl/src/gurl.h"
+
+namespace extensions {
+
+struct RendererContentMatchData {
+  RendererContentMatchData();
+  ~RendererContentMatchData();
+  GURL page_url;
+  base::hash_set<std::string> css_rules;
+};
+
+// Representation of a condition in the Declarative Content API. A condition
+// consists of an optional URL and a list of CSS selectors. Each of these
+// attributes needs to be fulfilled in order for the condition to be fulfilled.
+//
+// We distinguish between two types of attributes:
+// - URL Matcher attributes are attributes that test the URL of a page.
+//   These are treated separately because we use a URLMatcher to efficiently
+//   test many of these attributes in parallel by using some advanced
+//   data structures. The URLMatcher tells us if all URL Matcher attributes
+//   are fulfilled for a ContentCondition.
+// - All other conditions are represented individually as fields in
+//   ContentCondition.  These conditions are probed linearly (only if the URL
+//   Matcher found a hit).
+//
+// TODO(battre) Consider making the URLMatcher an owner of the
+// URLMatcherConditionSet and only pass a pointer to URLMatcherConditionSet
+// in url_matcher_condition_set(). This saves some copying in
+// ContentConditionSet::GetURLMatcherConditionSets.
+class ContentCondition {
+ public:
+  typedef RendererContentMatchData MatchData;
+
+  ContentCondition(
+      scoped_refptr<URLMatcherConditionSet> url_matcher_conditions,
+      const std::vector<std::string>& css_rules);
+  ~ContentCondition();
+
+  // Factory method that instantiates a ContentCondition according to the
+  // description |condition| passed by the extension API.  |condition| should be
+  // an instance of declarativeContent.PageStateMatcher.
+  static scoped_ptr<ContentCondition> Create(
+      URLMatcherConditionFactory* url_matcher_condition_factory,
+      const base::Value& condition,
+      std::string* error);
+
+  // Returns whether the request is a match, given that the URLMatcher found
+  // a match for |url_matcher_conditions_|.
+  bool IsFulfilled(const std::set<URLMatcherConditionSet::ID>& url_matches,
+                   const RendererContentMatchData& renderer_data) const;
+
+  // Returns a URLMatcherConditionSet::ID which is the canonical representation
+  // for all URL patterns that need to be matched by this ContentCondition.
+  // This ID is registered in a URLMatcher that can inform us in case of a
+  // match.
+  URLMatcherConditionSet::ID url_matcher_condition_set_id() const {
+    return url_matcher_conditions_->id();
+  }
+
+  // If this Condition has a url filter, appends it to |condition_sets|.
+  void GetURLMatcherConditionSets(
+      URLMatcherConditionSet::Vector* condition_sets) const {
+    if (url_matcher_conditions_)
+      condition_sets->push_back(url_matcher_conditions_);
+  }
+
+  // True if GetURLMatcherConditionSets would append anything to its
+  // argument.
+  bool has_url_matcher_condition_set() const {
+    return url_matcher_conditions_ != NULL;
+  }
+
+  // Returns the CSS rules required to match by this condition.
+  const std::vector<std::string>& css_rules() const {
+    return css_rules_;
+  }
+
+ private:
+  scoped_refptr<URLMatcherConditionSet> url_matcher_conditions_;
+  std::vector<std::string> css_rules_;
+
+  DISALLOW_COPY_AND_ASSIGN(ContentCondition);
+};
+
+typedef DeclarativeConditionSet<ContentCondition> ContentConditionSet;
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_CONTENT_CONTENT_CONDITION_H_