Beginning of support for extension content verification

extensions/browser/content_verify_job.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_VERIFY_JOB_H_
+#define EXTENSIONS_BROWSER_CONTENT_VERIFY_JOB_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/threading/thread_checker.h"
+
+namespace base {
+class FilePath;
+}
+
+namespace extensions {
+
+class ContentHashReader;
+
+// Objects of this class are responsible for verifying that the actual content
+// read from an extension file matches an expected set of hashes. This class
+// can be created on any thread but the rest of the methods should be called
+// from only one thread.
+class ContentVerifyJob : public base::RefCountedThreadSafe<ContentVerifyJob> {
+ public:
+  enum FailureReason {
+    // No failure.
+    NONE,
+
+    // Failed because there were no expected hashes.
+    NO_HASHES,
+
+    // Some of the content read did not match the expected hash.
+    HASH_MISMATCH
+  };
+  typedef base::Callback<void(FailureReason)> FailureCallback;
+
+  // The |failure_callback| will be called at most once if there was a failure.
+  //
+  // IMPORTANT NOTE: this class is still a stub right now - in the future this
+  // constructor will also be passed information to let it lookup expected
+  // block hashes for the file being read.
+  ContentVerifyJob(const std::string& extension_id,
+                   const FailureCallback& failure_callback);
+
+  // This begins the process of getting expected hashes, so it should be called
+  // as early as possible.
+  void Start();
+
+  // Call this to add more bytes to verify. If at any point the read bytes
+  // don't match the expected hashes, this will dispatch the failure
+  // callback. The failure callback will only be run once even if more bytes
+  // are read. Make sure to call DoneReading so that any final bytes that were
+  // read that didn't align exactly on a block size boundary get their hash
+  // checked as well.
+  void BytesRead(int count, const char* data);
+
+  // Call once when finished adding bytes via BytesRead.
+  void DoneReading();
+
+  class TestDelegate {
+   public:
+    // These methods will be called inside BytesRead/DoneReading respectively.
+    // If either return something other than NONE, then the failure callback
+    // will be dispatched with that reason.
+    virtual FailureReason BytesRead(const std::string& extension_id,
+                                    int count,
+                                    const char* data) = 0;
+    virtual FailureReason DoneReading(const std::string& extension_id) = 0;
+  };
+
+  static void SetDelegateForTests(TestDelegate* delegate);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ContentVerifyJob);
+
+  virtual ~ContentVerifyJob();
+  friend class base::RefCountedThreadSafe<ContentVerifyJob>;
+
+  void DispatchFailureCallback(FailureReason reason);
+
+  // The id of the extension for the file being verified.
+  std::string extension_id_;
+
+  // Called once if verification fails.
+  FailureCallback failure_callback_;
+
+  // For ensuring methods on called on the right thread.
+  base::ThreadChecker thread_checker_;
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_CONTENT_VERIFY_JOB_H_