FileDescriptorDataSource

Artifact: androidx.media3:media3-datasource

Kotlin |Java

@UnstableApi
class FileDescriptorDataSource : BaseDataSource

kotlin.Any
↳	androidx.media3.datasource.BaseDataSource
	↳	androidx.media3.datasource.FileDescriptorDataSource

A DataSource for reading from a FileDescriptor.

Due to limitations of file descriptors, it's only possible to have one DataSource created for a given file descriptor open at a time. The provided file descriptor must be seekable.

Unlike typical DataSource instances, each instance of this class can only read from a single FileDescriptor. Additionally, the uri passed to open is not actually used for reading data. Instead, the underlying is used for all read operations.

Summary

Public constructors
`FileDescriptorDataSource( fileDescriptor: FileDescriptor!, offset: Long, length: Long )` Creates a new instance.

Public functions
`Unit`	`close()` Closes the source.
`Long`	`open(dataSpec: DataSpec!)` Opens the source to read the specified data.
`Int`	`read(buffer: ByteArray!, offset: Int, length: Int)` Reads up to `length` bytes of data from the input.

Public properties
`Uri?`	`uri`

Inherited functions

From androidx.media3.datasource.BaseDataSource

`Unit`	`@UnstableApi addTransferListener(transferListener: TransferListener!)` Adds a `TransferListener` to listen to data transfers.
`Unit`	`bytesTransferred(bytesTransferred: Int)` Notifies listeners that bytes were transferred.
`Unit`	`transferEnded()` Notifies listeners that a transfer ended.
`Unit`	`transferInitializing(dataSpec: DataSpec!)` Notifies listeners that data transfer for the specified `DataSpec` is being initialized.
`Unit`	`transferStarted(dataSpec: DataSpec!)` Notifies listeners that data transfer for the specified `DataSpec` started.

From androidx.media3.datasource.DataSource

(Mutable)Map<String!, (Mutable)List<String!>!>!

@UnstableApi
getResponseHeaders()

When the source is open, returns the response headers associated with the last open call.

Public constructors

FileDescriptorDataSource

FileDescriptorDataSource(
    fileDescriptor: FileDescriptor!,
    offset: Long,
    length: Long
)

Creates a new instance.

Parameters
`fileDescriptor: FileDescriptor!`	The file descriptor from which to read.
`offset: Long`	The start offset of data to read.
`length: Long`	The length of data to read, or `LENGTH_UNSET` if not known.

Public functions

close

fun close(): Unit

Closes the source. This method must be called even if the corresponding call to open threw an IOException.

Throws
`java.io.IOException`	If an error occurs closing the source.
`androidx.media3.datasource.DataSourceException`

open

fun open(dataSpec: DataSpec!): Long

Opens the source to read the specified data. If an IOException is thrown, callers must still call close to ensure that any partial effects of the invocation are cleaned up.

The following edge case behaviors apply:

If the requested position is within the resource, but the requested length extends beyond the end of the resource, then open will succeed and data from the requested position to the end of the resource will be made available through read.
If the requested position is equal to the length of the resource, then open will succeed, and read will immediately return RESULT_END_OF_INPUT.
If the requested position is greater than the length of the resource, then open will throw an IOException for which isCausedByPositionOutOfRange will be true.

Parameters
`dataSpec: DataSpec!`	Defines the data to be read.

Returns
`Long`	The number of bytes that can be read from the opened source. For unbounded requests (i.e., requests where `length` equals `LENGTH_UNSET`) this value is the resolved length of the request, or `LENGTH_UNSET` if the length is still unresolved. For all other requests, the value returned will be equal to the request's `length`.

Throws
`java.io.IOException`	If an error occurs opening the source. `DataSourceException` can be thrown or used as a cause of the thrown exception to specify the reason of the error.
`androidx.media3.datasource.DataSourceException`

read

fun read(buffer: ByteArray!, offset: Int, length: Int): Int

Reads up to length bytes of data from the input.

If readLength is zero then 0 is returned. Otherwise, if no data is available because the end of the opened range has been reached, then RESULT_END_OF_INPUT is returned. Otherwise, the call will block until at least one byte of data has been read and the number of bytes read is returned.

Parameters
`buffer: ByteArray!`	A target array into which data should be written.
`offset: Int`	The offset into the target array at which to write.
`length: Int`	The maximum number of bytes to read from the input.

Returns
`Int`	The number of bytes read, or `RESULT_END_OF_INPUT` if the input has ended. This may be less than `length` because the end of the input (or available data) was reached, the method was interrupted, or the operation was aborted early for another reason.

Throws
`java.io.IOException`	If an error occurs reading from the input.
`androidx.media3.datasource.DataSourceException`

Public properties

uri

val uri: Uri?