Improve error messaging of webRequest API in case of conflicts

chrome/browser/extensions/extension_warning_set.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_EXTENSION_WARNING_SET_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_WARNING_SET_H_
 
 #include <set>
 #include <string>
+#include <vector>
 
-#include "base/string16.h"
+#include "googleurl/src/gurl.h"
 
-class ExtensionWarning;
-class ExtensionGlobalErrorBadge;
-class Profile;
+// TODO(battre) Remove the Extension prefix.
 
-// A set of warnings caused by extensions. These warnings (e.g. conflicting
-// modifications of network requests by extensions, slow extensions, etc.)
-// trigger a warning badge in the UI and and provide means to resolve them.
-class ExtensionWarningSet {
+class ExtensionSet;
+
+namespace extensions {
+
+// This class is used by the ExtensionWarningService to represent warnings if
+// extensions misbehave. Note that the ExtensionWarningService deals only with
+// specific warnings that should trigger a badge on the Chrome menu button.
+class ExtensionWarning {
  public:
   enum WarningType {
     // Don't use this, it is only intended for the default constructor and
     // does not have localized warning messages for the UI.
     kInvalid = 0,
     // An extension caused excessive network delays.
     kNetworkDelay,
     // This extension failed to modify a network request because the
     // modification conflicted with a modification of another extension.
     kNetworkConflict,
+    // This extension failed to redirect a network request because another
+    // extension with higher precedence redirected to a different target.
+    kRedirectConflict,
     // The extension repeatedly flushed WebKit's in-memory cache, which slows
     // down the overall performance.
     kRepeatedCacheFlushes,
     kMaxWarningType
   };
 
-  // Returns a localized string describing |warning_type|.
-  static string16 GetLocalizedWarning(WarningType warning_type);
+  // We allow copy&assign for passing containers of ExtensionWarnings between
+  // threads.
+  ExtensionWarning(const ExtensionWarning& other);
+  ~ExtensionWarning();
+  ExtensionWarning& operator=(const ExtensionWarning& other);
 
-  // |profile| may be NULL for testing. In this case, be sure to not insert
-  // any warnings.
-  explicit ExtensionWarningSet(Profile* profile);
-  virtual ~ExtensionWarningSet();
+  // Factory methods for various warning types.
+  static ExtensionWarning CreateNetworkDelayWarning(
+      const std::string& extension_id);
+  static ExtensionWarning CreateNetworkConflictWarning(
+      const std::string& extension_id);
+  static ExtensionWarning CreateRedirectConflictWarning(
+      const std::string& extension_id,
+      const std::string& winning_extension_id,
+      const GURL& attempted_redirect_url,
+      const GURL& winning_redirect_url);
+  static ExtensionWarning CreateRequestHeaderConflictWarning(
+      const std::string& extension_id,
+      const std::string& winning_extension_id,
+      const std::string& conflicting_header);
+  static ExtensionWarning CreateResponseHeaderConflictWarning(
+      const std::string& extension_id,
+      const std::string& winning_extension_id,
+      const std::string& conflicting_header);
+  static ExtensionWarning CreateCredentialsConflictWarning(
+      const std::string& extension_id,
+      const std::string& winning_extension_id);
+  static ExtensionWarning CreateRepeatedCacheFlushesWarning(
+      const std::string& extension_id);
 
-  // Adds a warning and triggers a chrome::NOTIFICATION_EXTENSION_WARNING
-  // message if this warning is is new. If the warning is new and has not
-  // been suppressed, this may activate a badge on the wrench menu.
-  void SetWarning(ExtensionWarningSet::WarningType type,
-                  const std::string& extension_id);
+  // Returns the specific warning type.
+  WarningType warning_type() const { return type_; }
 
-  // Clears all warnings of types contained in |types| and triggers a
-  // chrome::NOTIFICATION_EXTENSION_WARNING message if such warnings existed.
-  // If no warning remains that is not suppressed, this may deactivate a
-  // warning badge on the wrench mennu.
-  void ClearWarnings(const std::set<WarningType>& types);
+  // Returns the id of the extension for which this warning is valid.
+  const std::string& extension_id() const { return extension_id_; }
 
-  // Suppresses showing a badge for all currently existing warnings in the
-  // future.
-  void SuppressBadgeForCurrentWarnings();
-
-  // Stores all warnings for extension |extension_id| in |result|. The previous
-  // content of |result| is erased.
-  void GetWarningsAffectingExtension(
-      const std::string& extension_id,
-      std::set<WarningType>* result) const;
-
-  // Notifies the ExtensionWarningSet of profile |profile_id| that
-  // |extension_ids| caused warning |warning_type|. This function must only be
-  // called on the UI thread.
-  static void NotifyWarningsOnUI(void* profile_id,
-                                 std::set<std::string> extension_ids,
-                                 WarningType warning_type);
-
- protected:
-  // Virtual for testing.
-  virtual void NotifyWarningsChanged();
+  // Returns a localized warning message.
+  std::string GetLocalizedMessage(const ExtensionSet* extensions) const;
 
  private:
-  typedef std::set<ExtensionWarning>::const_iterator const_iterator;
-  typedef std::set<ExtensionWarning>::iterator iterator;
+  // Constructs a warning of type |type| for extension |extension_id|. This
+  // could indicate for example the fact that an extension conflicted with
+  // others. The |message_id| refers to an IDS_ string ID. The
+  // |message_parameters| are filled into the message template.
+  ExtensionWarning(WarningType type,
+                   const std::string& extension_id,
+                   int message_id,
+                   const std::vector<std::string>& message_parameters);
 
-  // Shows or hides the warning badge on the wrench menu depending on whether
-  // any non-suppressed warnings exist.
-  void UpdateWarningBadge();
-
-  // Currently existing warnings.
-  std::set<ExtensionWarning> warnings_;
-
-  // Warnings that do not trigger a badge on the wrench menu.
-  std::set<ExtensionWarning> badge_suppressions_;
-
-  Profile* profile_;
+  WarningType type_;
+  std::string extension_id_;
+  // IDS_* resource ID.
+  int message_id_;
+  // Parameters to be filled into the string identified by |message_id_|.
+  std::vector<std::string> message_parameters_;
 };
 
+// Compare ExtensionWarnings based on the tuple of (extension_id, type).
+// The message associated with ExtensionWarnings is purely informational
+// and does not contribute to distinguishing extensions.
+bool operator<(const ExtensionWarning& a, const ExtensionWarning& b);
+
+typedef std::set<ExtensionWarning> ExtensionWarningSet;
+
+}  // namespace extensions
+
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_WARNING_SET_H_