Index: content/browser/download/base_file.h |
diff --git a/content/browser/download/base_file.h b/content/browser/download/base_file.h |
index 8351c49be340654f99fce3e0f41477ecb77f65a6..39470a36043c46f70d1b2bd4b6387f427c38c66f 100644 |
--- a/content/browser/download/base_file.h |
+++ b/content/browser/download/base_file.h |
@@ -33,6 +33,13 @@ namespace content { |
// Detach(). |
class CONTENT_EXPORT BaseFile { |
public: |
+ // Enum to indicate whether the file is exclusived owned, or shared among |
+ // multiple writers. |
+ enum AccessMode { |
+ EXCLUSIVE = 0, |
+ SHARED, |
asanka
2017/02/16 18:46:26
I'd argue that the distinction is that the file is
qinmin
2017/02/16 21:35:50
Done. Changed this to a boolean variable is_sparse
|
+ }; |
+ |
// May be constructed on any thread. All other routines (including |
// destruction) must occur on the FILE thread. |
BaseFile(const net::NetLogWithSource& net_log); |
@@ -61,36 +68,52 @@ class CONTENT_EXPORT BaseFile { |
// will not attempt to determine the |full_path|. |
// |
// |bytes_so_far|: If a file is provided (via |full_path| or |file|), then |
- // this argument specifies the size of the file to expect. It is legal for |
- // the file to be larger, in which case the file will be truncated down to |
- // this size. However, if the file is shorter, then the operation will |
+ // this argument specifies the amount of data that has been written to |
+ // the file. If |access_mode| is EXCLUSIVE, this value should be the size |
+ // of the file to expect. It is legal for the file to be larger, in which |
+ // case the file will be truncated down to this size if |access_mode| is |
+ // EXCLUSIVE. However, if the file is shorter, then the operation will |
// fail with DOWNLOAD_INTERRUPT_REASON_FILE_TOO_SHORT. |
+ |
// |
- // |hash_so_far|: If |bytes_so_far| is non-zero, this specifies the SHA-256 |
- // hash of the first |bytes_so_far| bytes of the target file. If |
- // specified, BaseFile will read the first |bytes_so_far| of the target |
- // file in order to calculate the hash and verify that the file matches. |
- // If there's a mismatch, then the operation fails with |
- // DOWNLOAD_INTERRUPT_REASON_FILE_HASH_MISMATCH. Not used if |hash_state| |
- // is also specified. |
+ // |hash_so_far|: If |bytes_so_far| is non-zero and |access_mode| is |
+ // EXCLUSIVE, this specifies the SHA-256 hash of the first |bytes_so_far| |
+ // bytes of the target file. If specified, BaseFile will read the first |
+ // |bytes_so_far| of the target file in order to calculate the hash and |
+ // verify that the file matches. If there's a mismatch, then the operation |
+ // fails with DOWNLOAD_INTERRUPT_REASON_FILE_HASH_MISMATCH. Not used if |
+ // |hash_state| is also specified. |
// |
// |hash_state|: The partial hash object to use. Only meaningful if there's a |
// preexisting target file and it is non-empty (i.e. bytes_so_far is |
// non-zero). If specified, BaseFile will assume that the bytes up to |
// |bytes_so_far| has been accurately hashed into |hash_state| and will |
- // ignore |hash_so_far|. |
+ // ignore |hash_so_far|. Not used if |access_mode| is SHARED. |
+ // |
+ // |access_mode|: Specifies whether the file is going to be accessed by |
+ // multiple writers. If so, it is possible that one writer can request |
+ // writing to an offset that is larger than the file size. |
DownloadInterruptReason Initialize( |
const base::FilePath& full_path, |
const base::FilePath& default_directory, |
base::File file, |
int64_t bytes_so_far, |
const std::string& hash_so_far, |
- std::unique_ptr<crypto::SecureHash> hash_state); |
+ std::unique_ptr<crypto::SecureHash> hash_state, |
+ AccessMode access_mode); |
// Write a new chunk of data to the file. Returns a DownloadInterruptReason |
- // indicating the result of the operation. |
+ // indicating the result of the operation. Works only if |access_mode| is |
+ // EXCLUSIVE. |
DownloadInterruptReason AppendDataToFile(const char* data, size_t data_len); |
+ // Write a new chunk of data to the file. Returns a DownloadInterruptReason |
+ // indicating the result of the operation. |
+ DownloadInterruptReason WriteDataToFile( |
+ int64_t offset, |
+ const char* data, |
+ size_t data_len); |
+ |
// Rename the download file. Returns a DownloadInterruptReason indicating the |
// result of the operation. A return code of NONE indicates that the rename |
// was successful. After a failure, the full_path() and in_progress() can be |
@@ -137,7 +160,10 @@ class CONTENT_EXPORT BaseFile { |
// renamed. |
bool in_progress() const { return file_.IsValid(); } |
- // Returns the number of bytes in the file pointed to by full_path(). |
+ // Returns the number of bytes that has been written so far. If |access_mode_| |
+ // is EXCLUSIVE, this should always be equal to the file size. If |
+ // |access_mode_| is SHARED, this should not be larger than the file size |
+ // as the file may contain holes in it. |
int64_t bytes_so_far() const { return bytes_so_far_; } |
std::string DebugString() const; |
@@ -148,13 +174,15 @@ class CONTENT_EXPORT BaseFile { |
// Creates and opens the file_ if it is invalid. |
// |
- // If |hash_so_far| is not empty, then it must match the SHA-256 hash of the |
- // first |bytes_so_far_| bytes of |file_|. If there's a hash mismatch, Open() |
- // fails with DOWNLOAD_INTERRUPT_REASON_FILE_HASH_MISMATCH. |
+ // If |access_mode_| is EXCLUSIVE and |hash_so_far| is not empty, then it must |
+ // match the SHA-256 hash of the first |bytes_so_far_| bytes of |file_|. If |
+ // there's a hash mismatch, Open() fails with |
+ // DOWNLOAD_INTERRUPT_REASON_FILE_HASH_MISMATCH. |
// |
// If the opened file is shorter than |bytes_so_far_| bytes, then Open() fails |
- // with DOWNLOAD_INTERRUPT_REASON_FILE_TOO_SHORT. If the opened file is |
- // longer, then the file is truncated to |bytes_so_far_|. |
+ // with DOWNLOAD_INTERRUPT_REASON_FILE_TOO_SHORT. If the opened file is longer |
+ // and |access_mode_| is EXCLUSIVE, then the file is truncated to |
+ // |bytes_so_far_|. |
// |
// Open() can fail for other reasons as well. In that case, it returns a |
// relevant interrupt reason. Unless Open() return |
@@ -168,6 +196,9 @@ class CONTENT_EXPORT BaseFile { |
// Resets file_. |
void ClearFile(); |
+ // Writes data at the current position. |
+ DownloadInterruptReason WriteAtCurrentPos(const char* data, size_t data_len); |
+ |
// Platform specific method that moves a file to a new path and adjusts the |
// security descriptor / permissions on the file to match the defaults for the |
// new directory. |
@@ -177,7 +208,8 @@ class CONTENT_EXPORT BaseFile { |
// Split out from CurrentSpeed to enable testing. |
int64_t CurrentSpeedAtTime(base::TimeTicks current_time) const; |
- // Verifies that: |
+ // This function is only useful when |access_mode_| is EXCLUSIVE. It verifies |
asanka
2017/02/16 18:46:26
Once the download is complete, we'd still need use
qinmin
2017/02/16 21:35:50
Added the code to calculate the hash when finish()
|
+ // that: |
// * Size of the file represented by |file_| is at least |bytes_so_far_|. |
// |
// * If |hash_to_expect| is not empty, then the result of hashing the first |
@@ -222,6 +254,8 @@ class CONTENT_EXPORT BaseFile { |
// won't delete it on destruction. |
bool detached_ = false; |
+ AccessMode access_mode_ = EXCLUSIVE; |
+ |
net::NetLogWithSource net_log_; |
DISALLOW_COPY_AND_ASSIGN(BaseFile); |