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>

1 files changed, 6 insertions, 0 deletions

diff --git a/media/mtp/MtpDebug.cpp b/media/mtp/MtpDebug.cpp
index 1668ecf..9f3037d 100644
--- a/media/mtp/MtpDebug.cpp
+++ b/media/mtp/MtpDebug.cpp
@@ -63,6 +63,12 @@ static const CodeEntry sOperationCodes[] = {
     { "MTP_OPERATION_GET_OBJECT_REFERENCES",        0x9810 },
     { "MTP_OPERATION_SET_OBJECT_REFERENCES",        0x9811 },
     { "MTP_OPERATION_SKIP",                         0x9820 },
+    // android extensions
+    { "MTP_OPERATION_GET_PARTIAL_OBJECT_64",        0x95C1 },
+    { "MTP_OPERATION_SEND_PARTIAL_OBJECT",          0x95C2 },
+    { "MTP_OPERATION_TRUNCATE_OBJECT",              0x95C3 },
+    { "MTP_OPERATION_BEGIN_EDIT_OBJECT",            0x95C4 },
+    { "MTP_OPERATION_END_EDIT_OBJECT",              0x95C5 },
     { 0,                                            0      },
 };