Added member data to classes to support download resumption.

content/browser/download/download_item.h

Index: content/browser/download/download_item.h
diff --git a/content/browser/download/download_item.h b/content/browser/download/download_item.h
index 0e53e8d35d9e5522621760ae13708013d09e1548..6bda890b0d0767e370aaf3307b0ff598d12c31e1 100644
--- a/content/browser/download/download_item.h
+++ b/content/browser/download/download_item.h
@@ -146,8 +146,10 @@ class CONTENT_EXPORT DownloadItem {
   // Called when the user has validated the download of a dangerous file.
   void DangerousDownloadValidated();
 
-  // Received a new chunk of data
-  void Update(int64 bytes_so_far);
+  // Received a new chunk of data.
+  // |bytes_so_far| is the number of bytes received so far.
+  // |hash_state| is the current hash state.
+  void Update(int64 bytes_so_far, const std::string& hash_state);
 
   // Cancel the download operation. We need to distinguish between cancels at
   // exit (DownloadManager destructor) from user interface initiated cancels
@@ -176,8 +178,11 @@ class CONTENT_EXPORT DownloadItem {
 
   // Download operation had an error.
   // |size| is the amount of data received at interruption.
+  // |hash_state| is the current hash state at interruption.
   // |reason| is the download interrupt reason code that the operation received.
-  void Interrupted(int64 size, InterruptReason reason);
+  void Interrupted(int64 size,
+                   const std::string& hash_state,
+                   InterruptReason reason);
 
   // Deletes the file from disk and removes the download from the views and
   // history.  |user| should be true if this is the result of the user clicking
@@ -267,6 +272,7 @@ class CONTENT_EXPORT DownloadItem {
   }
   int64 received_bytes() const { return received_bytes_; }
   const std::string& hash() const { return hash_; }
+  std::string hash_state() const { return hash_state_; }
   int32 id() const { return download_id_.local(); }
   DownloadId global_id() const { return download_id_; }
   base::Time start_time() const { return start_time_; }
@@ -297,6 +303,9 @@ class CONTENT_EXPORT DownloadItem {
   void set_opened(bool opened) { opened_ = opened; }
   bool opened() const { return opened_; }
 
+  const std::string& last_modified_time() const { return last_modified_time_; }
+  const std::string& etag() const { return etag_; }
+
   InterruptReason last_reason() const { return last_reason_; }
 
   DownloadPersistentStoreInfo GetPersistentStoreInfo() const;
@@ -338,8 +347,14 @@ class CONTENT_EXPORT DownloadItem {
   // downloads and false for downloads from the history.
   void Init(bool active);
 
+  // Internal helper for maintaining consistent received and total sizes, and
+  // hash state.
+  void UpdateSizeAndHashState(int64 bytes_so_far,
+                              const std::string& hash_state);
+
   // Internal helper for maintaining consistent received and total sizes.
-  void UpdateSize(int64 size);
+  // Should only be called from |UpdateSizeAndHashState| and |OnAllDataSaved|.
+  void UpdateSize(int64 bytes_so_far);

[Randy Smith (Not in Mondays), 2011/11/22 17:37:49]

Given that the reason we have UpdateSizeAndHashState is to always keep the two
values in sync, I'd like to have functions at this level always update both
(where in these terms the hash state also includes the "Have we finished and do
we have a complete hash?")  

Maybe UpdateProgress and ProgressComplete (called when we're done)?  Those
functions have the advantage that they're talking about the higher level goals
of the functions, not about how they change the underlying data members.  Even
though these are private functions, so of the same principles of interface
design apply--you want the function names and arguments to be targeted at the
callers context, not the implementation of the function.

[ahendrickson, 2011/11/22 23:46:44]

Done.

 
   // Called when the entire download operation (including renaming etc)
   // is completed.
@@ -401,10 +416,10 @@ class CONTENT_EXPORT DownloadItem {
   // It's used to construct a suggested filename.
   std::string referrer_charset_;
 
-  // Total bytes expected
+  // Total bytes expected.
   int64 total_bytes_;
 
-  // Current received bytes
+  // Current received bytes.
   int64 received_bytes_;
 
   // Sha256 hash of the content.  This might be empty either because
@@ -412,31 +427,41 @@ class CONTENT_EXPORT DownloadItem {
   // (ChromeDownloadManagerDelegate::GenerateFileHash() returned false).
   std::string hash_;
 
+  // A blob containing the state of the hash algorithm.  Only valid while the
+  // hash is being computed.

[Randy Smith (Not in Mondays), 2011/11/22 17:37:49]

nit: At this level "while the hash is being computed" isn't really meaningful;
that's more a DownloadFile concept.  Maybe "until the download has completed".

[ahendrickson, 2011/11/22 23:46:44]

Done.

+  std::string hash_state_;
+
+  // Server's time stamp for the file.
+  std::string last_modified_time_;
+
+  // Server's ETAG for the file.
+  std::string etag_;
+
   // Last reason.
   InterruptReason last_reason_;
 
-  // Start time for calculating remaining time
+  // Start time for calculating remaining time.
   base::TimeTicks start_tick_;
 
-  // The current state of this download
+  // The current state of this download.
   DownloadState state_;
 
-  // The views of this item in the download shelf and download tab
+  // The views of this item in the download shelf and download tab.
   ObserverList<Observer> observers_;
 
-  // Time the download was started
+  // Time the download was started.
   base::Time start_time_;
 
-  // Time the download completed
+  // Time the download completed.
   base::Time end_time_;
 
-  // Our persistent store handle
+  // Our persistent store handle.
   int64 db_handle_;
 
-  // Our owning object
+  // Our owning object.
   DownloadManager* download_manager_;
 
-  // In progress downloads may be paused by the user, we note it here
+  // In progress downloads may be paused by the user, we note it here.
   bool is_paused_;
 
   // A flag for indicating if the download should be opened at completion.