Implementation of beginning of Declarative Web Request API backend

chrome/browser/extensions/api/declarative_webrequest/webrequest_condition_attribute.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_WEBREQUEST_WEBREQUEST_CONDITION_ATTRIBUTE_H_
+#define CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_WEBREQUEST_WEBREQUEST_CONDITION_ATTRIBUTE_H_
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/memory/linked_ptr.h"
+#include "tools/json_schema_compiler/any.h"
+
+namespace net {
+class URLRequest;
+}
+
+namespace extensions {
+namespace declarative_webrequest {
+
+// Base class for all condition attributes of the declarative Web Request API
+// except for condition attribute to test URLPatterns.
+class WebRequestConditionAttribute {
+ public:
+  enum Types {
+    CONDITION_HAS_SCHEME
+  };
+
+  WebRequestConditionAttribute();
+  virtual ~WebRequestConditionAttribute();
+
+  // Returns a bit vector representing extensions::RequestStages. The bit vector
+  // contains a 1 for each request stage during which the condition attribute
+  // can be tested.
+  virtual int GetStages() const = 0;
+
+  // Returns whether the condition is fulfilled for this request.
+  virtual bool IsFulfilled(net::URLRequest* request) = 0;
+
+  virtual Types type() const = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(WebRequestConditionAttribute);
+};
+
+typedef std::vector<linked_ptr<WebRequestConditionAttribute> >
+    WebRequestConditionAttributes;
+
+class WebRequestConditionAttributeFactory {
+ public:
+  // Returns whether conditions of type |instance_type| are handled by this
+  // factory.
+  static bool IsHandledByThisFactory(const std::string& instance_type);
+
+  // Creates a WebRequestConditionAttribute for the JSON dictionary
+  // {|name|: |value|}. Sets |error| and returns NULL if something fails.
+  // The ownership of |value| remains at the caller.
+  static scoped_ptr<WebRequestConditionAttribute> Create(
+      const std::string& name,
+      const base::Value* value,
+      std::string* error);
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(WebRequestConditionAttributeFactory);
+};
+
+//
+// The following are concrete conditions
+//
+
+// Condition that checks whether a URL has a specific scheme.
+// TODO(battre): Generalize this to allow checking for multiple schemes.
+class WebRequestConditionAttributeHasScheme

[Matt Perry, 2012/03/22 23:07:25]

I'm still convinced this doesn't belong here. Can we move the scheme check into
URLMatcherCondition somehow? I forget why you chose not to put the scheme checks
in there.

If it's not possible, maybe there should be another layer on top of
URLMatcherConditionSet that finishes checking the URL.

[battre, 2012/03/26 18:35:51]

The reason for having this here was flexibility, i.e. checking for URLs that
match "http OR https".

I have added a TODO as this can be done nicely in a separate CL.

BTW: What about the port number? This is also a difficult beast because we might
want to test for alternative ports.

[Matt Perry, 2012/03/26 19:11:06]

I see. The main thing bothering me here is that the layering seems wrong. I
would expect there to be a suite of URL* conditions that match against the URL,
and some WebRequest* conditions on top of that that match other metadata in the
request (like headers). The URL stuff doesn't all have to be tied to the pattern
matcher. But I suppose the way you have it is OK for now, since I don't have a
better suggestion.

[battre, 2012/03/26 20:38:10]

We can improve this, but I suggest to do it in two separate CLs.

1) Make sure that there is only a single instance of each
URLMatcherConditionSet.

2) Now that we don't need to worry about the size of the URLMatcherConditionSet
so much, extend it to support filters for ports + schemes.

+    : public WebRequestConditionAttribute {
+ public:
+  virtual ~WebRequestConditionAttributeHasScheme();
+
+  static bool IsMatchingType(const std::string& instance_type);
+
+  static scoped_ptr<WebRequestConditionAttribute> Create(
+      const std::string& name,
+      const base::Value* value,
+      std::string* error);
+
+  virtual int GetStages() const OVERRIDE;
+  virtual bool IsFulfilled(net::URLRequest* request) OVERRIDE;
+  virtual Types type() const OVERRIDE { return CONDITION_HAS_SCHEME; }
+
+ private:
+  explicit WebRequestConditionAttributeHasScheme(const std::string& pattern);
+  std::string pattern_;
+
+  DISALLOW_COPY_AND_ASSIGN(WebRequestConditionAttributeHasScheme);
+};
+
+}  // namespace declarative_webrequest
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_WEBREQUEST_WEBREQUEST_CONDITION_ATTRIBUTE_H_