components/update_client/component_patcher.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // Component updates can be either differential updates or full updates.
   6 // Full updates come in CRX format; differential updates come in CRX-style
   7 // archives, but have a different magic number. They contain "commands.json", a
   8 // list of commands for the patcher to follow. The patcher uses these commands,
   9 // the other files in the archive, and the files from the existing installation
  10 // of the component to create the contents of a full update, which is then
  11 // installed normally.
  12 // Component updates are specified by the 'codebasediff' attribute of an
  13 // updatecheck response:
  14 //   <updatecheck codebase="http://example.com/extension_1.2.3.4.crx"
  15 //                hash="12345" size="9854" status="ok" version="1.2.3.4"
  16 //                prodversionmin="2.0.143.0"
  17 //                codebasediff="http://example.com/diff_1.2.3.4.crx"
  18 //                hashdiff="123" sizediff="101"
  19 //                fp="1.123" />
  20 // The component updater will attempt a differential update if it is available
  21 // and allowed to, and fall back to a full update if it fails.
  22 //
  23 // After installation (diff or full), the component updater records "fp", the
  24 // fingerprint of the installed files, to later identify the existing files to
  25 // the server so that a proper differential update can be provided next cycle.
  26
  27 #ifndef COMPONENTS_UPDATE_CLIENT_COMPONENT_PATCHER_H_
  28 #define COMPONENTS_UPDATE_CLIENT_COMPONENT_PATCHER_H_
  29
  30 #include "base/callback_forward.h"
  31 #include "base/macros.h"
  32 #include "base/memory/ref_counted.h"
  33 #include "base/memory/scoped_ptr.h"
  34 #include "base/values.h"
  35 #include "components/update_client/component_unpacker.h"
  36
  37 namespace base {
  38 class FilePath;
  39 }
  40
  41 namespace update_client {
  42
  43 class ComponentInstaller;
  44 class DeltaUpdateOp;
  45 class OutOfProcessPatcher;
  46
  47 // The type of a patch file.
  48 enum PatchType {
  49   kPatchTypeUnknown,
  50   kPatchTypeCourgette,
  51   kPatchTypeBsdiff,
  52 };
  53
  54 // Encapsulates a task for applying a differential update to a component.
  55 class ComponentPatcher : public base::RefCountedThreadSafe<ComponentPatcher> {
  56  public:
  57   // Takes an unpacked differential CRX (|input_dir|) and a component installer,
  58   // and sets up the class to create a new (non-differential) unpacked CRX.
  59   // If |in_process| is true, patching will be done completely within the
  60   // existing process. Otherwise, some steps of patching may be done
  61   // out-of-process.
  62   ComponentPatcher(const base::FilePath& input_dir,
  63                    const base::FilePath& unpack_dir,
  64                    scoped_refptr<ComponentInstaller> installer,
  65                    scoped_refptr<OutOfProcessPatcher> out_of_process_patcher,
  66                    scoped_refptr<base::SequencedTaskRunner> task_runner);
  67
  68   // Starts patching files. This member function returns immediately, after
  69   // posting a task to do the patching. When patching has been completed,
  70   // |callback| will be called with the error codes if any error codes were
  71   // encountered.
  72   void Start(const ComponentUnpacker::Callback& callback);
  73
  74  private:
  75   friend class base::RefCountedThreadSafe<ComponentPatcher>;
  76
  77   virtual ~ComponentPatcher();
  78
  79   void StartPatching();
  80
  81   void PatchNextFile();
  82
  83   void DonePatchingFile(ComponentUnpacker::Error error, int extended_error);
  84
  85   void DonePatching(ComponentUnpacker::Error error, int extended_error);
  86
  87   const base::FilePath input_dir_;
  88   const base::FilePath unpack_dir_;
  89   scoped_refptr<ComponentInstaller> installer_;
  90   scoped_refptr<OutOfProcessPatcher> out_of_process_patcher_;
  91   ComponentUnpacker::Callback callback_;
  92   scoped_ptr<base::ListValue> commands_;
  93   base::ValueVector::const_iterator next_command_;
  94   scoped_refptr<DeltaUpdateOp> current_operation_;
  95   scoped_refptr<base::SequencedTaskRunner> task_runner_;
  96
  97   DISALLOW_COPY_AND_ASSIGN(ComponentPatcher);
  98 };
  99
 100 }  // namespace update_client
 101
 102 #endif  // COMPONENTS_UPDATE_CLIENT_COMPONENT_PATCHER_H_