Adding condition attributes for response headers to Declarative WebRequest

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_
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/linked_ptr.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/scoped_vector.h"
 #include "chrome/browser/extensions/api/declarative_webrequest/request_stage.h"
 #include "chrome/browser/extensions/api/declarative_webrequest/webrequest_rule.h"
 #include "chrome/common/extensions/api/events.h"
 #include "webkit/glue/resource_type.h"
 
 namespace base {
 class Value;
 }
 
 namespace net {
 class URLRequest;
 }
 
 namespace extensions {
 
 // Base class for all condition attributes of the declarative Web Request API
 // except for condition attribute to test URLPatterns.
 class WebRequestConditionAttribute {
  public:
   enum Type {
     CONDITION_RESOURCE_TYPE,
-    CONDITION_CONTENT_TYPE
+    CONDITION_CONTENT_TYPE,
+    CONDITION_REQUEST_HEADERS
   };
 
   WebRequestConditionAttribute();
   virtual ~WebRequestConditionAttribute();
 
   // Factory method that creates a WebRequestConditionAttribute for the JSON
   // dictionary {|name|: |value|} passed by the extension API. 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);
 
   // Returns a bit vector representing extensions::RequestStage. 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(const WebRequestRule::RequestData& request_data) = 0;
+  virtual bool IsFulfilled(
+      const WebRequestRule::RequestData& request_data) const = 0;
 
   virtual Type GetType() const = 0;
 
   // Returns whether condition attributes of type |instance_type| are known
   // and can be instantiated by Create().
   static bool IsKnownType(const std::string& instance_type);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(WebRequestConditionAttribute);
 };
@@ skipping 14 matching lines @@
   static bool IsMatchingType(const std::string& instance_type);
 
   // Factory method, see WebRequestConditionAttribute::Create.
   static scoped_ptr<WebRequestConditionAttribute> Create(
       const std::string& name,
       const base::Value* value,
       std::string* error);
 
   // Implementation of WebRequestConditionAttribute:
   virtual int GetStages() const OVERRIDE;
-  virtual bool IsFulfilled(const WebRequestRule::RequestData& request_data)
-      OVERRIDE;
+  virtual bool IsFulfilled(
+      const WebRequestRule::RequestData& request_data) const OVERRIDE;
   virtual Type GetType() const OVERRIDE;
 
  private:
   explicit WebRequestConditionAttributeResourceType(
       const std::vector<ResourceType::Type>& types);
 
   std::vector<ResourceType::Type> types_;
 
   DISALLOW_COPY_AND_ASSIGN(WebRequestConditionAttributeResourceType);
 };
 
 // Condition that checks whether a response's Content-Type header has a
 // certain MIME media type.
 class WebRequestConditionAttributeContentType
     : public WebRequestConditionAttribute {
  public:
   virtual ~WebRequestConditionAttributeContentType();
 
   static bool IsMatchingType(const std::string& instance_type);
 
   // Factory method, see WebRequestConditionAttribute::Create.
   static scoped_ptr<WebRequestConditionAttribute> Create(
       const std::string& name,
       const base::Value* value,
       std::string* error);
 
   // Implementation of WebRequestConditionAttribute:
   virtual int GetStages() const OVERRIDE;
-  virtual bool IsFulfilled(const WebRequestRule::RequestData& request_data)
-      OVERRIDE;
+  virtual bool IsFulfilled(
+      const WebRequestRule::RequestData& request_data) const OVERRIDE;
   virtual Type GetType() const OVERRIDE;
 
  private:
   explicit WebRequestConditionAttributeContentType(
       const std::vector<std::string>& include_content_types,
       bool inclusive);
 
   std::vector<std::string> content_types_;
   bool inclusive_;
 
   DISALLOW_COPY_AND_ASSIGN(WebRequestConditionAttributeContentType);
 };
 
+// Condition that performs matches against response headers' names and values.
+// In the comments below there is a distinction between when this condition is
+// "satisfied" and when it is "fulfilled". See the comments at |tests_| for
+// "satisfied" and the comment at |positive_test_| for "fulfilled".
+class WebRequestConditionAttributeResponseHeaders
+    : public WebRequestConditionAttribute {
+ public:
+  virtual ~WebRequestConditionAttributeResponseHeaders();
+
+  static bool IsMatchingType(const std::string& instance_type);
+
+  // Factory method, see WebRequestConditionAttribute::Create.
+  static scoped_ptr<WebRequestConditionAttribute> Create(
+      const std::string& name,
+      const base::Value* value,
+      std::string* error);
+
+  // Implementation of WebRequestConditionAttribute:
+  virtual int GetStages() const OVERRIDE;
+  virtual bool IsFulfilled(
+      const WebRequestRule::RequestData& request_data) const OVERRIDE;
+  virtual Type GetType() const OVERRIDE;
+
+ private:
+  enum MatchType { kPrefix, kSuffix, kEquals, kContains };
+
+  class MatchTest {
+   public:
+    // Takes ownership of |data|, which must not be NULL.
+    MatchTest(scoped_ptr<const std::string> data, MatchType type);

[battre, 2012/08/24 16:24:41]

Please pass |data| just as a const ref. The cost to copy the string once is not
that big.

[vabr (Chromium), 2012/08/27 12:11:50]

Done.
To document this decision:
pros of the scoped_ptr:
* saving one copy of the string defining the test
cons:
* complicating the code with a separate memory management for that string
* non-standard way of doing this

Because this only happens once per rule registration (not rule usage), the pros
are not significant enough to counter the cons.

+    ~MatchTest();
+    const std::string& data() const {
+      return *(data_.get());
+    }
+    // Does |str| pass |*this| MatchTest?
+    bool Matches(const std::string& str) const;
+   private:
+    const scoped_ptr<const std::string> data_;
+    const MatchType type_;
+    DISALLOW_COPY_AND_ASSIGN(MatchTest);
+  };
+
+  class TestGroup {
+   public:
+    TestGroup(ScopedVector<const MatchTest>* name,

[battre, 2012/08/24 16:24:41]

Please add comment, that ownership is taken over.

[vabr (Chromium), 2012/08/27 12:11:50]

Done.

+              ScopedVector<const MatchTest>* value);
+    ~TestGroup();
+    // Does the header |name|: |value| match all tests in this test group?
+    bool Matches(const std::string& name, const std::string& value) const;
+   private:
+    // Tests to be passed by a header's name.
+    const ScopedVector<const MatchTest> name_;
+    // Tests to be passed by a header's value.
+    const ScopedVector<const MatchTest> value_;
+    DISALLOW_COPY_AND_ASSIGN(TestGroup);
+  };
+
+  explicit WebRequestConditionAttributeResponseHeaders(bool positive_test);
+
+  // Gets the tests' description in |tests| and creates the corresponding
+  // TestGroup. Returns NULL on failure.
+  static scoped_ptr<const TestGroup> GetTests(

[battre, 2012/08/24 16:24:41]

nit: s/Get/Create/?

[vabr (Chromium), 2012/08/27 12:11:50]

Done.

+      const base::DictionaryValue* tests,
+      std::string* error);
+  // Helper to GetTests. Never returns NULL, except for memory failures.
+  static scoped_ptr<const MatchTest> GetMatchTest(const Value* content,
+                                                  bool is_name_test,
+                                                  MatchType match_type);

[battre, 2012/08/24 16:24:41]

nit: s/Get/Create/ (also in line 203)

[vabr (Chromium), 2012/08/27 12:11:50]

Done.

+
+  // The condition is satisfied if there is a header and its value such that for
+  // some |i| the header passes all the tests from |tests_[i]|.
+  ScopedVector<const TestGroup> tests_;
+
+  // True means that IsFulfilled() reports whether the condition is satisfied.
+  // False means that it reports whether the condition is NOT satisfied.
+  bool positive_test_;
+
+  DISALLOW_COPY_AND_ASSIGN(WebRequestConditionAttributeResponseHeaders);
+};
+
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_WEBREQUEST_WEBREQUEST_CONDITION_ATTRIBUTE_H_