Added member data to classes to support download resumption.

content/browser/download/base_file.h

Index: content/browser/download/base_file.h
diff --git a/content/browser/download/base_file.h b/content/browser/download/base_file.h
index 08a0a981618ec2cc43207f6ca6077ac1a18c1972..69c937f482ca215528813905de1ba79bf03c0e93 100644
--- a/content/browser/download/base_file.h
+++ b/content/browser/download/base_file.h
@@ -34,12 +34,13 @@ class CONTENT_EXPORT BaseFile {
            const GURL& source_url,
            const GURL& referrer_url,
            int64 received_bytes,
+           bool calculate_hash,
+           const std::string& hash_state,
            const linked_ptr<net::FileStream>& file_stream);
   virtual ~BaseFile();
 
-  // If calculate_hash is true, sha256 hash will be calculated.
   // Returns net::OK on success, or a network error code on failure.
-  net::Error Initialize(bool calculate_hash);
+  net::Error Initialize();
 
   // Write a new chunk of data to the file.
   // Returns net::OK on success (all bytes written to the file),
@@ -69,14 +70,17 @@ class CONTENT_EXPORT BaseFile {
   bool in_progress() const { return file_stream_ != NULL; }
   int64 bytes_so_far() const { return bytes_so_far_; }
 
-  // Set |hash| with sha256 digest for the file.
+  // Fills |hash| with the sha256 digest for the file.

[Randy Smith (Not in Mondays), 2011/12/20 17:05:40]

Basic question: Is the fact that the hash is an sha256 hash part of the
interface?  I.e. does anything outside of download file and crypto need to know
about it?  If yes, then I'll retract my earlier request that the interfaces not
name the type of hash.  If not, then the comment shouldn't refer to it either.

Now that I ask the question, I'm somewhat afraid that the safebrowsing system
*does* need to know that it's sha256, since it's comparing against stored
hashes.  Which means I was wrong in my initial comment.  But either way, the
comments and interface should be in alignment, and the naming/commenting should
be based on whether external customers need to know what kind of hash it is.  

[ahendrickson, 2011/12/20 22:06:54]

Changed the comments to match the functions.

   // Returns true if digest is successfully calculated.
-  virtual bool GetSha256Hash(std::string* hash);
+  virtual bool GetHash(std::string* hash);
+
+  // Returns the current (intermediate) state of the hash as a byte string.
+  virtual std::string GetHashState();
 
   // Returns true if the given hash is considered empty.  An empty hash is
   // a string of size kSha256HashLen that contains only zeros (initial value
   // for the hash).
-  static bool IsEmptySha256Hash(const std::string& hash);
+  static bool IsEmptyHash(const std::string& hash);
 
   virtual std::string DebugString() const;
 
@@ -91,11 +95,14 @@ class CONTENT_EXPORT BaseFile {
 
  private:
   friend class BaseFileTest;
-  FRIEND_TEST_ALL_PREFIXES(BaseFileTest, IsEmptySha256Hash);
+  FRIEND_TEST_ALL_PREFIXES(BaseFileTest, IsEmptyHash);
 
   // Split out from CurrentSpeed to enable testing.
   int64 CurrentSpeedAtTime(base::TimeTicks current_time) const;
 
+  // Resets the current state of the hash to the contents of |hash_state_bytes|.
+  virtual bool SetHashState(const std::string& hash_state_bytes);
+
   static const size_t kSha256HashLen = 32;
   static const unsigned char kEmptySha256Hash[kSha256HashLen];