ProxyFileDescriptorCallback
abstract class ProxyFileDescriptorCallback
Callback that handles file system requests from ProxyFileDescriptor. All callback methods except for onRelease should throw android.system.ErrnoException
with proper errno on errors. See errno(3) and android.system.OsConstants
. Typical errnos are
Summary
Public methods |
open Unit |
Ensures all the written data are stored in permanent storage device.
|
open Long |
Returns size of bytes provided by the file descriptor.
|
open Int |
Provides bytes read from file descriptor.
|
abstract Unit |
Invoked after the file is closed.
|
open Int |
Handles bytes written to file descriptor.
|
Public constructors
ProxyFileDescriptorCallback
ProxyFileDescriptorCallback()
Public methods
onFsync
open fun onFsync(): Unit
Ensures all the written data are stored in permanent storage device. For example, if it has data stored in on memory cache, it needs to flush data to storage device.
Exceptions |
android.system.ErrnoException |
ErrnoException containing E constants in OsConstants. |
onGetSize
open fun onGetSize(): Long
Returns size of bytes provided by the file descriptor.
Return |
Long |
Size of bytes. |
Exceptions |
android.system.ErrnoException |
ErrnoException containing E constants in OsConstants. |
onRead
open fun onRead(
offset: Long,
size: Int,
data: ByteArray!
): Int
Provides bytes read from file descriptor. It needs to return exact requested size of bytes unless it reaches file end.
Parameters |
offset |
Long: Offset in bytes from the file head specifying where to read bytes. If a seek operation is conducted on the file descriptor, then a read operation is requested, the offset refrects the proper position of requested bytes. |
size |
Int: Size for read bytes. |
data |
ByteArray!: Byte array to store read bytes. |
Return |
Int |
Size of bytes returned by the function. |
Exceptions |
android.system.ErrnoException |
ErrnoException containing E constants in OsConstants. |
onRelease
abstract fun onRelease(): Unit
Invoked after the file is closed.
onWrite
open fun onWrite(
offset: Long,
size: Int,
data: ByteArray!
): Int
Handles bytes written to file descriptor.
Parameters |
offset |
Long: Offset in bytes from the file head specifying where to write bytes. If a seek operation is conducted on the file descriptor, then a write operation is requested, the offset refrects the proper position of requested bytes. |
size |
Int: Size for write bytes. |
data |
ByteArray!: Byte array to be written to somewhere. |
Return |
Int |
Size of bytes processed by the function. |
Exceptions |
android.system.ErrnoException |
ErrnoException containing E constants in OsConstants. |