Session
open class Session : Closeable
| kotlin.Any | |
| ↳ | android.app.blob.BlobStoreManager.Session |
Represents an ongoing session of a blob's contribution to the blob store managed by the system.
Clients that want to contribute a blob need to first create a Session using createSession(android.app.blob.BlobHandle) and once the session is created, clients can open and close this session multiple times using openSession(long) and android.app.blob.BlobStoreManager.Session#close() before committing it using Session.commit(Executor, Consumer), at which point system will take ownership of the blob and the client can no longer make any modifications to the blob's content.
Summary
| Public methods | |
|---|---|
| open Unit |
abandon()Abandon this session and delete any data that was written to this session so far. |
| open Unit |
allowPackageAccess(packageName: String, certificate: ByteArray)Allow |
| open Unit |
Allow any app on the device to access this blob data once it is committed using a |
| open Unit |
Allow packages which are signed with the same certificate as the caller to access this blob data once it is committed using a |
| open Unit |
close()Close this session. |
| open Unit |
Commit the file that was written so far to this session to the blob store maintained by the system. |
| open Long |
getSize()Gets the size of the blob file that was written to the session so far. |
| open Boolean |
isPackageAccessAllowed(packageName: String, certificate: ByteArray)Returns |
| open Boolean |
Returns |
| open Boolean |
Returns |
| open ParcelFileDescriptor |
openRead()Opens a file descriptor to read the blob content already written into this session. |
| open ParcelFileDescriptor |
Opens a file descriptor to write a blob into the session. |
Public methods
abandon
open fun abandon(): Unit
Abandon this session and delete any data that was written to this session so far.
| Exceptions | |
|---|---|
java.io.IOException |
when there is an I/O error while abandoning the session. |
java.lang.SecurityException |
when the caller is not the owner of the session. |
java.lang.IllegalStateException |
when the caller tries to abandon a session which was already finalized. |
allowPackageAccess
open fun allowPackageAccess(
packageName: String,
certificate: ByteArray
): Unit
Allow packageName with a particular signing certificate to access this blob data once it is committed using a BlobHandle representing the blob.
This needs to be called before committing the blob using commit(java.util.concurrent.Executor,java.util.function.Consumer).
| Parameters | |
|---|---|
packageName |
String: the name of the package which should be allowed to access the blob. This value cannot be null. |
certificate |
ByteArray: the input bytes representing a certificate of type android.content.pm.PackageManager#CERT_INPUT_SHA256. This value cannot be null. |
| Exceptions | |
|---|---|
java.io.IOException |
when there is an I/O error while changing the access. |
java.lang.SecurityException |
when the caller is not the owner of the session. |
java.lang.IllegalStateException |
when the caller tries to change access for a blob which is already committed. |
android.os.LimitExceededException |
when the caller tries to explicitly allow too many packages using this API. |
allowPublicAccess
open fun allowPublicAccess(): Unit
Allow any app on the device to access this blob data once it is committed using a BlobHandle representing the blob.
Note: This is only meant to be used from libraries and SDKs where the apps which we want to allow access is not known ahead of time. If a blob is being committed to be shared with a particular set of apps, it is highly recommended to use allowPackageAccess(java.lang.String,byte[]) instead.
This needs to be called before committing the blob using commit(java.util.concurrent.Executor,java.util.function.Consumer).
| Exceptions | |
|---|---|
java.io.IOException |
when there is an I/O error while changing the access. |
java.lang.SecurityException |
when the caller is not the owner of the session. |
java.lang.IllegalStateException |
when the caller tries to change access for a blob which is already committed. |
allowSameSignatureAccess
open fun allowSameSignatureAccess(): Unit
Allow packages which are signed with the same certificate as the caller to access this blob data once it is committed using a BlobHandle representing the blob.
This needs to be called before committing the blob using commit(java.util.concurrent.Executor,java.util.function.Consumer).
| Exceptions | |
|---|---|
java.io.IOException |
when there is an I/O error while changing the access. |
java.lang.SecurityException |
when the caller is not the owner of the session. |
java.lang.IllegalStateException |
when the caller tries to change access for a blob which is already committed. |
close
open fun close(): Unit
Close this session. It can be re-opened for writing/reading if it has not been abandoned (using abandon) or committed (using commit).
| Exceptions | |
|---|---|
java.lang.Exception |
if this resource cannot be closed |
java.io.IOException |
when there is an I/O error while closing the session. |
java.lang.SecurityException |
when the caller is not the owner of the session. |
commit
open fun commit(
executor: Executor,
resultCallback: Consumer<Int!>
): Unit
Commit the file that was written so far to this session to the blob store maintained by the system.
Once this method is called, the session is finalized and no additional mutations can be performed on the session. If the device reboots before the session has been finalized, you may commit the session again.
Note that this commit operation will fail if the hash of the data written so far to this session does not match with the one used for BlobHandle.createWithSha256(byte[], CharSequence, long, String) BlobHandle} associated with this session.
Committing the same data more than once will result in replacing the corresponding access mode (via calling one of allowPackageAccess(java.lang.String,byte[]), allowSameSignatureAccess(), etc) with the latest one.
| Parameters | |
|---|---|
executor |
Executor: the executor on which result callback will be invoked. This value cannot be null. Callback and listener events are dispatched through this Executor, providing an easy way to control which thread is used. To dispatch events through the main thread of your application, you can use Context.getMainExecutor(). Otherwise, provide an Executor that dispatches to an appropriate thread. |
resultCallback |
Consumer<Int!>: a callback to receive the commit result. when the result is 0, it indicates success. Otherwise, failure. This value cannot be null. |
| Exceptions | |
|---|---|
java.io.IOException |
when there is an I/O error while committing the session. |
java.lang.SecurityException |
when the caller is not the owner of the session. |
java.lang.IllegalArgumentException |
when the passed parameters are not valid. |
java.lang.IllegalStateException |
when the caller tries to commit a session which was already finalized. |
getSize
open fun getSize(): Long
Gets the size of the blob file that was written to the session so far.
Value is a non-negative number of bytes.
| Return | |
|---|---|
Long |
the size of the blob file so far. Value is a non-negative number of bytes. |
| Exceptions | |
|---|---|
java.io.IOException |
when there is an I/O error while opening the file to read. |
java.lang.SecurityException |
when the caller is not the owner of the session. |
java.lang.IllegalStateException |
when the caller tries to get the file size after it is abandoned (using abandon()) or closed (using #close()). |
isPackageAccessAllowed
open fun isPackageAccessAllowed(
packageName: String,
certificate: ByteArray
): Boolean
Returns true if access has been allowed for a packageName using either allowPackageAccess(java.lang.String,byte[]). Otherwise, false.
| Parameters | |
|---|---|
packageName |
String: the name of the package to check the access for. This value cannot be null. |
certificate |
ByteArray: the input bytes representing a certificate of type android.content.pm.PackageManager#CERT_INPUT_SHA256. This value cannot be null. |
| Exceptions | |
|---|---|
java.io.IOException |
when there is an I/O error while getting the access type. |
java.lang.IllegalStateException |
when the caller tries to get access type from a session which is closed or abandoned. |
isPublicAccessAllowed
open fun isPublicAccessAllowed(): Boolean
Returns true if public access has been allowed by using allowPublicAccess(). Otherwise, false.
| Exceptions | |
|---|---|
java.io.IOException |
when there is an I/O error while getting the access type. |
java.lang.IllegalStateException |
when the caller tries to get access type from a session which is closed or abandoned. |
isSameSignatureAccessAllowed
open fun isSameSignatureAccessAllowed(): Boolean
Returns true if access has been allowed for packages signed with the same certificate as the caller by using allowSameSignatureAccess(). Otherwise, false.
| Exceptions | |
|---|---|
java.io.IOException |
when there is an I/O error while getting the access type. |
java.lang.IllegalStateException |
when the caller tries to get access type from a session which is closed or abandoned. |
openRead
open fun openRead(): ParcelFileDescriptor
Opens a file descriptor to read the blob content already written into this session.
| Return | |
|---|---|
ParcelFileDescriptor |
a ParcelFileDescriptor for reading from the blob file. This value cannot be null. |
| Exceptions | |
|---|---|
java.io.IOException |
when there is an I/O error while opening the file to read. |
java.lang.SecurityException |
when the caller is not the owner of the session. |
java.lang.IllegalStateException |
when the caller tries to read the file after it is abandoned (using abandon()) or closed (using #close()). |
openWrite
open fun openWrite(
offsetBytes: Long,
lengthBytes: Long
): ParcelFileDescriptor
Opens a file descriptor to write a blob into the session.
The returned file descriptor will start writing data at the requested offset in the underlying file, which can be used to resume a partially written file. If a valid file length is specified, the system will preallocate the underlying disk space to optimize placement on disk. It is strongly recommended to provide a valid file length when known.
| Parameters | |
|---|---|
offsetBytes |
Long: offset into the file to begin writing at, or 0 to start at the beginning of the file. Value is a non-negative number of bytes. |
lengthBytes |
Long: total size of the file being written, used to preallocate the underlying disk space, or -1 if unknown. The system may clear various caches as needed to allocate this space. Value is a non-negative number of bytes. |
| Return | |
|---|---|
ParcelFileDescriptor |
a ParcelFileDescriptor for writing to the blob file. This value cannot be null. |
| Exceptions | |
|---|---|
java.io.IOException |
when there is an I/O error while opening the file to write. |
java.lang.SecurityException |
when the caller is not the owner of the session. |
java.lang.IllegalStateException |
when the caller tries to write to the file after it is abandoned (using abandon()) or committed (using commit) or closed (using #close()). |