MTP: Add extended operations to support in-place editing of files
MTP does not support partial writes of files (the entire file must be transferred at once).
This makes it impossible to implement a FUSE file system for MTP
with acceptable performance.
To fix this problem, this change adds extended MTP operations to allow
partial writes to files:
SendPartialObject - allows writing a subset of a file, or appending to the end of a file
TruncateObject - allows changing the size of a file
BeginEditObject - must be called before using SendPartialObject and TruncateObject
EndEditObject - commits changes to a file after it has been edited with SendPartialObject or TruncateObject
We also add GetPartialObject64, which is the same as GetPartialObject
but has a 64 bit offset rather than 32.
Change-Id: I4b110748b97ae05cdc8aab02ecdbbbeb263f7840
Signed-off-by: Mike Lockwood <lockwood@android.com>
diff --git a/media/mtp/mtp.h b/media/mtp/mtp.h
index 8bc2e22..d270df5 100644
--- a/media/mtp/mtp.h
+++ b/media/mtp/mtp.h
@@ -391,6 +391,19 @@
#define MTP_OPERATION_SET_OBJECT_REFERENCES 0x9811
#define MTP_OPERATION_SKIP 0x9820
+// Android extensions for direct file IO
+
+// Same as GetPartialObject, but with 64 bit offset
+#define MTP_OPERATION_GET_PARTIAL_OBJECT_64 0x95C1
+// Same as GetPartialObject64, but copying host to device
+#define MTP_OPERATION_SEND_PARTIAL_OBJECT 0x95C2
+// Truncates file to 64 bit length
+#define MTP_OPERATION_TRUNCATE_OBJECT 0x95C3
+// Must be called before using SendPartialObject and TruncateObject
+#define MTP_OPERATION_BEGIN_EDIT_OBJECT 0x95C4
+// Called to commit changes made by SendPartialObject and TruncateObject
+#define MTP_OPERATION_END_EDIT_OBJECT 0x95C5
+
// MTP Response Codes
#define MTP_RESPONSE_UNDEFINED 0x2000
#define MTP_RESPONSE_OK 0x2001