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      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_COMPONENT_UPDATER_COMPONENT_PATCHER_H_
     28 #define COMPONENTS_COMPONENT_UPDATER_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/component_updater/component_unpacker.h"
     36 
     37 namespace base {
     38 class FilePath;
     39 }
     40 
     41 namespace component_updater {
     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                    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   ComponentInstaller* const 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 component_updater
    101 
    102 #endif  // COMPONENTS_COMPONENT_UPDATER_COMPONENT_PATCHER_H_
    103