Content Verification: Don't access UI-thread objects on the IO thread

extensions/browser/content_verifier.h

 // 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 EXTENSIONS_BROWSER_CONTENT_VERIFIER_H_
 #define EXTENSIONS_BROWSER_CONTENT_VERIFIER_H_
 
 #include <set>
 #include <string>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/scoped_observer.h"
+#include "base/version.h"
+#include "extensions/browser/content_verifier_delegate.h"
 #include "extensions/browser/content_verify_job.h"
+#include "extensions/browser/extension_registry_observer.h"
 
 namespace base {
 class FilePath;
 }
 
 namespace content {
 class BrowserContext;
 }
 
 namespace extensions {
 
 class Extension;
 class ContentHashFetcher;
-class ContentVerifierDelegate;
+class ContentVerifierIOData;
 
 // Used for managing overall content verification - both fetching content
 // hashes as needed, and supplying job objects to verify file contents as they
 // are read.
-class ContentVerifier : public base::RefCountedThreadSafe<ContentVerifier> {
+class ContentVerifier : public base::RefCountedThreadSafe<ContentVerifier>,
+                        public ExtensionRegistryObserver {
  public:
   // Takes ownership of |delegate|.
   ContentVerifier(content::BrowserContext* context,
                   ContentVerifierDelegate* delegate);
   void Start();
   void Shutdown();
 
   // Call this before reading a file within an extension. The caller owns the
   // returned job.
   ContentVerifyJob* CreateJobFor(const std::string& extension_id,
                                  const base::FilePath& extension_root,
                                  const base::FilePath& relative_path);
 
   // Called (typically by a verification job) to indicate that verification
   // failed while reading some file in |extension_id|.
   void VerifyFailed(const std::string& extension_id,
                     ContentVerifyJob::FailureReason reason);
 
-  void OnFetchComplete(const std::string& extension_id,
-                       bool success,
-                       bool was_force_check,
-                       const std::set<base::FilePath>& hash_mismatch_paths);
+  // ExtensionRegistryObserver interface
+  virtual void OnExtensionLoaded(content::BrowserContext* browser_context,
+                                 const Extension* extension) OVERRIDE;
+  virtual void OnExtensionUnloaded(
+      content::BrowserContext* browser_context,
+      const Extension* extension,
+      UnloadedExtensionInfo::Reason reason) OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ContentVerifier);
 
   friend class base::RefCountedThreadSafe<ContentVerifier>;
   virtual ~ContentVerifier();
 
+  void OnFetchComplete(const std::string& extension_id,
+                       bool success,
+                       bool was_force_check,
+                       const std::set<base::FilePath>& hash_mismatch_paths);
+
+  void OnFetchCompleteHelper(const std::string& extension_id,
+                             bool shouldVerifyAnyPathsResult);
+
   // Returns true if any of the paths in |relative_paths| *should* have their
   // contents verified. (Some files get transcoded during the install process,
   // so we don't want to verify their contents because they are expected not
   // to match).
-  bool ShouldVerifyAnyPaths(const Extension* extension,
+  bool ShouldVerifyAnyPaths(const std::string& extension_id,
+                            const base::FilePath& extension_root,
                             const std::set<base::FilePath>& relative_paths);
 
+  // Set to true once we've begun shutting down.
+  bool shutdown_;
+
   content::BrowserContext* context_;
 
   scoped_ptr<ContentVerifierDelegate> delegate_;
 
   // For fetching content hash signatures.
   scoped_ptr<ContentHashFetcher> fetcher_;
+
+  // For observing the ExtensionRegistry.
+  ScopedObserver<ExtensionRegistry, ExtensionRegistryObserver> observer_;
+
+  // Data that should only be used on the IO thread.
+  scoped_refptr<ContentVerifierIOData> io_data_;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_CONTENT_VERIFIER_H_