Download resumption - Preliminary

content/browser/download/download_item_impl.h

Index: content/browser/download/download_item_impl.h
diff --git a/content/browser/download/download_item_impl.h b/content/browser/download/download_item_impl.h
index 797c798bda9e7ab50833b635c7af1379a172d8cc..35ec719d7ebea75b561124ba0c931bb5859d6e62 100644
--- a/content/browser/download/download_item_impl.h
+++ b/content/browser/download/download_item_impl.h
@@ -33,6 +33,17 @@ class CONTENT_EXPORT DownloadItemImpl
     : public DownloadItem,
       public DownloadDestinationObserver {
  public:
+  enum ResumeMode {
+    RESUME_MODE_INVALID = 0,
+    RESUME_MODE_IMMEDIATE_CONTINUE,
+    RESUME_MODE_IMMEDIATE_RESTART,
+    RESUME_MODE_USER_CONTINUE,
+    RESUME_MODE_USER_RESTART
+  };
+
+  // The maximum number of attempts we will make to resume automatically.
+  static const int kMaxAutoResumeAttempts;
+
   // Note that it is the responsibility of the caller to ensure that a
   // DownloadItemImplDelegate passed to a DownloadItemImpl constructor
   // outlives the DownloadItemImpl.
@@ -56,7 +67,6 @@ class CONTENT_EXPORT DownloadItemImpl
   // |bound_net_log| is constructed externally for our use.
   DownloadItemImpl(DownloadItemImplDelegate* delegate,
                    const DownloadCreateInfo& info,
-                   scoped_ptr<DownloadRequestHandleInterface> request_handle,
                    const net::BoundNetLog& bound_net_log);
 
   // Constructing for the "Save Page As..." feature:
@@ -86,6 +96,7 @@ class CONTENT_EXPORT DownloadItemImpl
   virtual DownloadState GetState() const OVERRIDE;
   virtual DownloadInterruptReason GetLastReason() const OVERRIDE;
   virtual bool IsPaused() const OVERRIDE;
+  virtual bool CanResumeInterrupted() const OVERRIDE;
   virtual bool IsTemporary() const OVERRIDE;
   virtual bool IsPartialDownload() const OVERRIDE;
   virtual bool IsInProgress() const OVERRIDE;
@@ -128,6 +139,7 @@ class CONTENT_EXPORT DownloadItemImpl
   virtual base::Time GetEndTime() const OVERRIDE;
   virtual bool CanShowInFolder() OVERRIDE;
   virtual bool CanOpenDownload() OVERRIDE;
+  virtual bool CanResumeDownload() const OVERRIDE;
   virtual bool ShouldOpenFileBasedOnExtension() OVERRIDE;
   virtual bool GetOpenWhenComplete() const OVERRIDE;
   virtual bool GetAutoOpened() OVERRIDE;
@@ -141,25 +153,32 @@ class CONTENT_EXPORT DownloadItemImpl
   virtual void SetDisplayName(const FilePath& name) OVERRIDE;
   virtual std::string DebugString(bool verbose) const OVERRIDE;
   virtual void MockDownloadOpenForTesting() OVERRIDE;
+  virtual const net::BoundNetLog& GetBoundNetLog() const OVERRIDE;
 
   // All remaining public interfaces virtual to allow for DownloadItemImpl
   // mocks.
 
+  virtual bool IsResuming() const;
+  virtual ResumeMode GetResumeMode() const;
+
   // Main entry points for regular downloads, in order -------------------------
 
   // TODO(rdsmith): Fold the process that uses these fully into
   // DownloadItemImpl and pass callbacks to the delegate so that all of
   // these other than Start() can be made private.
 
-  // Start the download
-  virtual void Start(scoped_ptr<DownloadFile> download_file);
+  // Start the download.
+  // |download_file| is the associated file on the storage medium.
+  // |req_handle| is the new request handle associated with the download.
+  virtual void Start(scoped_ptr<DownloadFile> download_file,
+                     scoped_ptr<DownloadRequestHandleInterface> req_handle);
 
   // If all pre-requisites have been met, complete download processing, i.e. do
   // internal cleanup, file rename, and potentially auto-open.  (Dangerous
   // downloads still may block on user acceptance after this point.)
   virtual void MaybeCompleteDownload();
 
-  // Needed because of interwining with DownloadManagerImpl --------------------
+  // Needed because of intertwining with DownloadManagerImpl -------------------
 
   // TODO(rdsmith): Unwind DownloadManagerImpl and DownloadItemImpl,
   // removing these from the public interface.
@@ -280,6 +299,9 @@ class CONTENT_EXPORT DownloadItemImpl
   // is completed.
   void Completed();
 
+  // Initiates a resume operation on an interrupted download.
+  void ResumeInterruptedDownload();
+
   // Helper routines -----------------------------------------------------------
 
   // Indicate that an error has occurred on the download.
@@ -299,7 +321,8 @@ class CONTENT_EXPORT DownloadItemImpl
 
   void SetFullPath(const FilePath& new_path);
 
-  // Mapping between internal and external states.
+  void AutoResumeIfValid();
+
   static DownloadState InternalToExternalState(
       DownloadInternalState internal_state);
   static DownloadInternalState ExternalToInternalState(
@@ -307,6 +330,7 @@ class CONTENT_EXPORT DownloadItemImpl
 
   // Debugging routines --------------------------------------------------------
   static const char* DebugDownloadStateString(DownloadInternalState state);
+  static const char* DebugResumeModeString(ResumeMode mode);
 
   // Will be false for save package downloads retrieved from the history.
   // TODO(rdsmith): Replace with a generalized enum for "download source".
@@ -425,6 +449,12 @@ class CONTENT_EXPORT DownloadItemImpl
   // In progress downloads may be paused by the user, we note it here.
   bool is_paused_;
 
+  // A download has been resumed.
+  bool is_resuming_;
+
+  // The number of times this download has been resumed automatically.
+  int auto_resume_count_;
+
   // A flag for indicating if the download should be opened at completion.
   bool open_when_complete_;