| /* |
| * Copyright (C) 2011 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package android.database.sqlite; |
| |
| import android.database.CursorWindow; |
| import android.database.DatabaseUtils; |
| import android.os.CancellationSignal; |
| import android.os.OperationCanceledException; |
| import android.os.ParcelFileDescriptor; |
| |
| /** |
| * Provides a single client the ability to use a database. |
| * |
| * <h2>About database sessions</h2> |
| * <p> |
| * Database access is always performed using a session. The session |
| * manages the lifecycle of transactions and database connections. |
| * </p><p> |
| * Sessions can be used to perform both read-only and read-write operations. |
| * There is some advantage to knowing when a session is being used for |
| * read-only purposes because the connection pool can optimize the use |
| * of the available connections to permit multiple read-only operations |
| * to execute in parallel whereas read-write operations may need to be serialized. |
| * </p><p> |
| * When <em>Write Ahead Logging (WAL)</em> is enabled, the database can |
| * execute simultaneous read-only and read-write transactions, provided that |
| * at most one read-write transaction is performed at a time. When WAL is not |
| * enabled, read-only transactions can execute in parallel but read-write |
| * transactions are mutually exclusive. |
| * </p> |
| * |
| * <h2>Ownership and concurrency guarantees</h2> |
| * <p> |
| * Session objects are not thread-safe. In fact, session objects are thread-bound. |
| * The {@link SQLiteDatabase} uses a thread-local variable to associate a session |
| * with each thread for the use of that thread alone. Consequently, each thread |
| * has its own session object and therefore its own transaction state independent |
| * of other threads. |
| * </p><p> |
| * A thread has at most one session per database. This constraint ensures that |
| * a thread can never use more than one database connection at a time for a |
| * given database. As the number of available database connections is limited, |
| * if a single thread tried to acquire multiple connections for the same database |
| * at the same time, it might deadlock. Therefore we allow there to be only |
| * one session (so, at most one connection) per thread per database. |
| * </p> |
| * |
| * <h2>Transactions</h2> |
| * <p> |
| * There are two kinds of transaction: implicit transactions and explicit |
| * transactions. |
| * </p><p> |
| * An implicit transaction is created whenever a database operation is requested |
| * and there is no explicit transaction currently in progress. An implicit transaction |
| * only lasts for the duration of the database operation in question and then it |
| * is ended. If the database operation was successful, then its changes are committed. |
| * </p><p> |
| * An explicit transaction is started by calling {@link #beginTransaction} and |
| * specifying the desired transaction mode. Once an explicit transaction has begun, |
| * all subsequent database operations will be performed as part of that transaction. |
| * To end an explicit transaction, first call {@link #setTransactionSuccessful} if the |
| * transaction was successful, then call {@link #end}. If the transaction was |
| * marked successful, its changes will be committed, otherwise they will be rolled back. |
| * </p><p> |
| * Explicit transactions can also be nested. A nested explicit transaction is |
| * started with {@link #beginTransaction}, marked successful with |
| * {@link #setTransactionSuccessful}and ended with {@link #endTransaction}. |
| * If any nested transaction is not marked successful, then the entire transaction |
| * including all of its nested transactions will be rolled back |
| * when the outermost transaction is ended. |
| * </p><p> |
| * To improve concurrency, an explicit transaction can be yielded by calling |
| * {@link #yieldTransaction}. If there is contention for use of the database, |
| * then yielding ends the current transaction, commits its changes, releases the |
| * database connection for use by another session for a little while, and starts a |
| * new transaction with the same properties as the original one. |
| * Changes committed by {@link #yieldTransaction} cannot be rolled back. |
| * </p><p> |
| * When a transaction is started, the client can provide a {@link SQLiteTransactionListener} |
| * to listen for notifications of transaction-related events. |
| * </p><p> |
| * Recommended usage: |
| * <code><pre> |
| * // First, begin the transaction. |
| * session.beginTransaction(SQLiteSession.TRANSACTION_MODE_DEFERRED, 0); |
| * try { |
| * // Then do stuff... |
| * session.execute("INSERT INTO ...", null, 0); |
| * |
| * // As the very last step before ending the transaction, mark it successful. |
| * session.setTransactionSuccessful(); |
| * } finally { |
| * // Finally, end the transaction. |
| * // This statement will commit the transaction if it was marked successful or |
| * // roll it back otherwise. |
| * session.endTransaction(); |
| * } |
| * </pre></code> |
| * </p> |
| * |
| * <h2>Database connections</h2> |
| * <p> |
| * A {@link SQLiteDatabase} can have multiple active sessions at the same |
| * time. Each session acquires and releases connections to the database |
| * as needed to perform each requested database transaction. If all connections |
| * are in use, then database transactions on some sessions will block until a |
| * connection becomes available. |
| * </p><p> |
| * The session acquires a single database connection only for the duration |
| * of a single (implicit or explicit) database transaction, then releases it. |
| * This characteristic allows a small pool of database connections to be shared |
| * efficiently by multiple sessions as long as they are not all trying to perform |
| * database transactions at the same time. |
| * </p> |
| * |
| * <h2>Responsiveness</h2> |
| * <p> |
| * Because there are a limited number of database connections and the session holds |
| * a database connection for the entire duration of a database transaction, |
| * it is important to keep transactions short. This is especially important |
| * for read-write transactions since they may block other transactions |
| * from executing. Consider calling {@link #yieldTransaction} periodically |
| * during long-running transactions. |
| * </p><p> |
| * Another important consideration is that transactions that take too long to |
| * run may cause the application UI to become unresponsive. Even if the transaction |
| * is executed in a background thread, the user will get bored and |
| * frustrated if the application shows no data for several seconds while |
| * a transaction runs. |
| * </p><p> |
| * Guidelines: |
| * <ul> |
| * <li>Do not perform database transactions on the UI thread.</li> |
| * <li>Keep database transactions as short as possible.</li> |
| * <li>Simple queries often run faster than complex queries.</li> |
| * <li>Measure the performance of your database transactions.</li> |
| * <li>Consider what will happen when the size of the data set grows. |
| * A query that works well on 100 rows may struggle with 10,000.</li> |
| * </ul> |
| * |
| * <h2>Reentrance</h2> |
| * <p> |
| * This class must tolerate reentrant execution of SQLite operations because |
| * triggers may call custom SQLite functions that perform additional queries. |
| * </p> |
| * |
| * @hide |
| */ |
| public final class SQLiteSession { |
| private final SQLiteConnectionPool mConnectionPool; |
| |
| private SQLiteConnection mConnection; |
| private int mConnectionFlags; |
| private int mConnectionUseCount; |
| private Transaction mTransactionPool; |
| private Transaction mTransactionStack; |
| |
| /** |
| * Transaction mode: Deferred. |
| * <p> |
| * In a deferred transaction, no locks are acquired on the database |
| * until the first operation is performed. If the first operation is |
| * read-only, then a <code>SHARED</code> lock is acquired, otherwise |
| * a <code>RESERVED</code> lock is acquired. |
| * </p><p> |
| * While holding a <code>SHARED</code> lock, this session is only allowed to |
| * read but other sessions are allowed to read or write. |
| * While holding a <code>RESERVED</code> lock, this session is allowed to read |
| * or write but other sessions are only allowed to read. |
| * </p><p> |
| * Because the lock is only acquired when needed in a deferred transaction, |
| * it is possible for another session to write to the database first before |
| * this session has a chance to do anything. |
| * </p><p> |
| * Corresponds to the SQLite <code>BEGIN DEFERRED</code> transaction mode. |
| * </p> |
| */ |
| public static final int TRANSACTION_MODE_DEFERRED = 0; |
| |
| /** |
| * Transaction mode: Immediate. |
| * <p> |
| * When an immediate transaction begins, the session acquires a |
| * <code>RESERVED</code> lock. |
| * </p><p> |
| * While holding a <code>RESERVED</code> lock, this session is allowed to read |
| * or write but other sessions are only allowed to read. |
| * </p><p> |
| * Corresponds to the SQLite <code>BEGIN IMMEDIATE</code> transaction mode. |
| * </p> |
| */ |
| public static final int TRANSACTION_MODE_IMMEDIATE = 1; |
| |
| /** |
| * Transaction mode: Exclusive. |
| * <p> |
| * When an exclusive transaction begins, the session acquires an |
| * <code>EXCLUSIVE</code> lock. |
| * </p><p> |
| * While holding an <code>EXCLUSIVE</code> lock, this session is allowed to read |
| * or write but no other sessions are allowed to access the database. |
| * </p><p> |
| * Corresponds to the SQLite <code>BEGIN EXCLUSIVE</code> transaction mode. |
| * </p> |
| */ |
| public static final int TRANSACTION_MODE_EXCLUSIVE = 2; |
| |
| /** |
| * Creates a session bound to the specified connection pool. |
| * |
| * @param connectionPool The connection pool. |
| */ |
| public SQLiteSession(SQLiteConnectionPool connectionPool) { |
| if (connectionPool == null) { |
| throw new IllegalArgumentException("connectionPool must not be null"); |
| } |
| |
| mConnectionPool = connectionPool; |
| } |
| |
| /** |
| * Returns true if the session has a transaction in progress. |
| * |
| * @return True if the session has a transaction in progress. |
| */ |
| public boolean hasTransaction() { |
| return mTransactionStack != null; |
| } |
| |
| /** |
| * Returns true if the session has a nested transaction in progress. |
| * |
| * @return True if the session has a nested transaction in progress. |
| */ |
| public boolean hasNestedTransaction() { |
| return mTransactionStack != null && mTransactionStack.mParent != null; |
| } |
| |
| /** |
| * Returns true if the session has an active database connection. |
| * |
| * @return True if the session has an active database connection. |
| */ |
| public boolean hasConnection() { |
| return mConnection != null; |
| } |
| |
| /** |
| * Begins a transaction. |
| * <p> |
| * Transactions may nest. If the transaction is not in progress, |
| * then a database connection is obtained and a new transaction is started. |
| * Otherwise, a nested transaction is started. |
| * </p><p> |
| * Each call to {@link #beginTransaction} must be matched exactly by a call |
| * to {@link #endTransaction}. To mark a transaction as successful, |
| * call {@link #setTransactionSuccessful} before calling {@link #endTransaction}. |
| * If the transaction is not successful, or if any of its nested |
| * transactions were not successful, then the entire transaction will |
| * be rolled back when the outermost transaction is ended. |
| * </p> |
| * |
| * @param transactionMode The transaction mode. One of: {@link #TRANSACTION_MODE_DEFERRED}, |
| * {@link #TRANSACTION_MODE_IMMEDIATE}, or {@link #TRANSACTION_MODE_EXCLUSIVE}. |
| * Ignored when creating a nested transaction. |
| * @param transactionListener The transaction listener, or null if none. |
| * @param connectionFlags The connection flags to use if a connection must be |
| * acquired by this operation. Refer to {@link SQLiteConnectionPool}. |
| * @param cancellationSignal A signal to cancel the operation in progress, or null if none. |
| * |
| * @throws IllegalStateException if {@link #setTransactionSuccessful} has already been |
| * called for the current transaction. |
| * @throws SQLiteException if an error occurs. |
| * @throws OperationCanceledException if the operation was canceled. |
| * |
| * @see #setTransactionSuccessful |
| * @see #yieldTransaction |
| * @see #endTransaction |
| */ |
| public void beginTransaction(int transactionMode, |
| SQLiteTransactionListener transactionListener, int connectionFlags, |
| CancellationSignal cancellationSignal) { |
| throwIfTransactionMarkedSuccessful(); |
| beginTransactionUnchecked(transactionMode, transactionListener, connectionFlags, |
| cancellationSignal); |
| } |
| |
| private void beginTransactionUnchecked(int transactionMode, |
| SQLiteTransactionListener transactionListener, int connectionFlags, |
| CancellationSignal cancellationSignal) { |
| if (cancellationSignal != null) { |
| cancellationSignal.throwIfCanceled(); |
| } |
| |
| if (mTransactionStack == null) { |
| acquireConnection(null, connectionFlags, cancellationSignal); // might throw |
| } |
| try { |
| // Set up the transaction such that we can back out safely |
| // in case we fail part way. |
| if (mTransactionStack == null) { |
| // Execute SQL might throw a runtime exception. |
| switch (transactionMode) { |
| case TRANSACTION_MODE_IMMEDIATE: |
| mConnection.execute("BEGIN IMMEDIATE;", null, |
| cancellationSignal); // might throw |
| break; |
| case TRANSACTION_MODE_EXCLUSIVE: |
| mConnection.execute("BEGIN EXCLUSIVE;", null, |
| cancellationSignal); // might throw |
| break; |
| default: |
| mConnection.execute("BEGIN;", null, cancellationSignal); // might throw |
| break; |
| } |
| } |
| |
| // Listener might throw a runtime exception. |
| if (transactionListener != null) { |
| try { |
| transactionListener.onBegin(); // might throw |
| } catch (RuntimeException ex) { |
| if (mTransactionStack == null) { |
| mConnection.execute("ROLLBACK;", null, cancellationSignal); // might throw |
| } |
| throw ex; |
| } |
| } |
| |
| // Bookkeeping can't throw, except an OOM, which is just too bad... |
| Transaction transaction = obtainTransaction(transactionMode, transactionListener); |
| transaction.mParent = mTransactionStack; |
| mTransactionStack = transaction; |
| } finally { |
| if (mTransactionStack == null) { |
| releaseConnection(); // might throw |
| } |
| } |
| } |
| |
| /** |
| * Marks the current transaction as having completed successfully. |
| * <p> |
| * This method can be called at most once between {@link #beginTransaction} and |
| * {@link #endTransaction} to indicate that the changes made by the transaction should be |
| * committed. If this method is not called, the changes will be rolled back |
| * when the transaction is ended. |
| * </p> |
| * |
| * @throws IllegalStateException if there is no current transaction, or if |
| * {@link #setTransactionSuccessful} has already been called for the current transaction. |
| * |
| * @see #beginTransaction |
| * @see #endTransaction |
| */ |
| public void setTransactionSuccessful() { |
| throwIfNoTransaction(); |
| throwIfTransactionMarkedSuccessful(); |
| |
| mTransactionStack.mMarkedSuccessful = true; |
| } |
| |
| /** |
| * Ends the current transaction and commits or rolls back changes. |
| * <p> |
| * If this is the outermost transaction (not nested within any other |
| * transaction), then the changes are committed if {@link #setTransactionSuccessful} |
| * was called or rolled back otherwise. |
| * </p><p> |
| * This method must be called exactly once for each call to {@link #beginTransaction}. |
| * </p> |
| * |
| * @param cancellationSignal A signal to cancel the operation in progress, or null if none. |
| * |
| * @throws IllegalStateException if there is no current transaction. |
| * @throws SQLiteException if an error occurs. |
| * @throws OperationCanceledException if the operation was canceled. |
| * |
| * @see #beginTransaction |
| * @see #setTransactionSuccessful |
| * @see #yieldTransaction |
| */ |
| public void endTransaction(CancellationSignal cancellationSignal) { |
| throwIfNoTransaction(); |
| assert mConnection != null; |
| |
| endTransactionUnchecked(cancellationSignal, false); |
| } |
| |
| private void endTransactionUnchecked(CancellationSignal cancellationSignal, boolean yielding) { |
| if (cancellationSignal != null) { |
| cancellationSignal.throwIfCanceled(); |
| } |
| |
| final Transaction top = mTransactionStack; |
| boolean successful = (top.mMarkedSuccessful || yielding) && !top.mChildFailed; |
| |
| RuntimeException listenerException = null; |
| final SQLiteTransactionListener listener = top.mListener; |
| if (listener != null) { |
| try { |
| if (successful) { |
| listener.onCommit(); // might throw |
| } else { |
| listener.onRollback(); // might throw |
| } |
| } catch (RuntimeException ex) { |
| listenerException = ex; |
| successful = false; |
| } |
| } |
| |
| mTransactionStack = top.mParent; |
| recycleTransaction(top); |
| |
| if (mTransactionStack != null) { |
| if (!successful) { |
| mTransactionStack.mChildFailed = true; |
| } |
| } else { |
| try { |
| if (successful) { |
| mConnection.execute("COMMIT;", null, cancellationSignal); // might throw |
| } else { |
| mConnection.execute("ROLLBACK;", null, cancellationSignal); // might throw |
| } |
| } finally { |
| releaseConnection(); // might throw |
| } |
| } |
| |
| if (listenerException != null) { |
| throw listenerException; |
| } |
| } |
| |
| /** |
| * Temporarily ends a transaction to let other threads have use of |
| * the database. Begins a new transaction after a specified delay. |
| * <p> |
| * If there are other threads waiting to acquire connections, |
| * then the current transaction is committed and the database |
| * connection is released. After a short delay, a new transaction |
| * is started. |
| * </p><p> |
| * The transaction is assumed to be successful so far. Do not call |
| * {@link #setTransactionSuccessful()} before calling this method. |
| * This method will fail if the transaction has already been marked |
| * successful. |
| * </p><p> |
| * The changes that were committed by a yield cannot be rolled back later. |
| * </p><p> |
| * Before this method was called, there must already have been |
| * a transaction in progress. When this method returns, there will |
| * still be a transaction in progress, either the same one as before |
| * or a new one if the transaction was actually yielded. |
| * </p><p> |
| * This method should not be called when there is a nested transaction |
| * in progress because it is not possible to yield a nested transaction. |
| * If <code>throwIfNested</code> is true, then attempting to yield |
| * a nested transaction will throw {@link IllegalStateException}, otherwise |
| * the method will return <code>false</code> in that case. |
| * </p><p> |
| * If there is no nested transaction in progress but a previous nested |
| * transaction failed, then the transaction is not yielded (because it |
| * must be rolled back) and this method returns <code>false</code>. |
| * </p> |
| * |
| * @param sleepAfterYieldDelayMillis A delay time to wait after yielding |
| * the database connection to allow other threads some time to run. |
| * If the value is less than or equal to zero, there will be no additional |
| * delay beyond the time it will take to begin a new transaction. |
| * @param throwIfUnsafe If true, then instead of returning false when no |
| * transaction is in progress, a nested transaction is in progress, or when |
| * the transaction has already been marked successful, throws {@link IllegalStateException}. |
| * @param cancellationSignal A signal to cancel the operation in progress, or null if none. |
| * @return True if the transaction was actually yielded. |
| * |
| * @throws IllegalStateException if <code>throwIfNested</code> is true and |
| * there is no current transaction, there is a nested transaction in progress or |
| * if {@link #setTransactionSuccessful} has already been called for the current transaction. |
| * @throws SQLiteException if an error occurs. |
| * @throws OperationCanceledException if the operation was canceled. |
| * |
| * @see #beginTransaction |
| * @see #endTransaction |
| */ |
| public boolean yieldTransaction(long sleepAfterYieldDelayMillis, boolean throwIfUnsafe, |
| CancellationSignal cancellationSignal) { |
| if (throwIfUnsafe) { |
| throwIfNoTransaction(); |
| throwIfTransactionMarkedSuccessful(); |
| throwIfNestedTransaction(); |
| } else { |
| if (mTransactionStack == null || mTransactionStack.mMarkedSuccessful |
| || mTransactionStack.mParent != null) { |
| return false; |
| } |
| } |
| assert mConnection != null; |
| |
| if (mTransactionStack.mChildFailed) { |
| return false; |
| } |
| |
| return yieldTransactionUnchecked(sleepAfterYieldDelayMillis, |
| cancellationSignal); // might throw |
| } |
| |
| private boolean yieldTransactionUnchecked(long sleepAfterYieldDelayMillis, |
| CancellationSignal cancellationSignal) { |
| if (cancellationSignal != null) { |
| cancellationSignal.throwIfCanceled(); |
| } |
| |
| if (!mConnectionPool.shouldYieldConnection(mConnection, mConnectionFlags)) { |
| return false; |
| } |
| |
| final int transactionMode = mTransactionStack.mMode; |
| final SQLiteTransactionListener listener = mTransactionStack.mListener; |
| final int connectionFlags = mConnectionFlags; |
| endTransactionUnchecked(cancellationSignal, true); // might throw |
| |
| if (sleepAfterYieldDelayMillis > 0) { |
| try { |
| Thread.sleep(sleepAfterYieldDelayMillis); |
| } catch (InterruptedException ex) { |
| // we have been interrupted, that's all we need to do |
| } |
| } |
| |
| beginTransactionUnchecked(transactionMode, listener, connectionFlags, |
| cancellationSignal); // might throw |
| return true; |
| } |
| |
| /** |
| * Prepares a statement for execution but does not bind its parameters or execute it. |
| * <p> |
| * This method can be used to check for syntax errors during compilation |
| * prior to execution of the statement. If the {@code outStatementInfo} argument |
| * is not null, the provided {@link SQLiteStatementInfo} object is populated |
| * with information about the statement. |
| * </p><p> |
| * A prepared statement makes no reference to the arguments that may eventually |
| * be bound to it, consequently it it possible to cache certain prepared statements |
| * such as SELECT or INSERT/UPDATE statements. If the statement is cacheable, |
| * then it will be stored in the cache for later and reused if possible. |
| * </p> |
| * |
| * @param sql The SQL statement to prepare. |
| * @param connectionFlags The connection flags to use if a connection must be |
| * acquired by this operation. Refer to {@link SQLiteConnectionPool}. |
| * @param cancellationSignal A signal to cancel the operation in progress, or null if none. |
| * @param outStatementInfo The {@link SQLiteStatementInfo} object to populate |
| * with information about the statement, or null if none. |
| * |
| * @throws SQLiteException if an error occurs, such as a syntax error. |
| * @throws OperationCanceledException if the operation was canceled. |
| */ |
| public void prepare(String sql, int connectionFlags, CancellationSignal cancellationSignal, |
| SQLiteStatementInfo outStatementInfo) { |
| if (sql == null) { |
| throw new IllegalArgumentException("sql must not be null."); |
| } |
| |
| if (cancellationSignal != null) { |
| cancellationSignal.throwIfCanceled(); |
| } |
| |
| acquireConnection(sql, connectionFlags, cancellationSignal); // might throw |
| try { |
| mConnection.prepare(sql, outStatementInfo); // might throw |
| } finally { |
| releaseConnection(); // might throw |
| } |
| } |
| |
| /** |
| * Executes a statement that does not return a result. |
| * |
| * @param sql The SQL statement to execute. |
| * @param bindArgs The arguments to bind, or null if none. |
| * @param connectionFlags The connection flags to use if a connection must be |
| * acquired by this operation. Refer to {@link SQLiteConnectionPool}. |
| * @param cancellationSignal A signal to cancel the operation in progress, or null if none. |
| * |
| * @throws SQLiteException if an error occurs, such as a syntax error |
| * or invalid number of bind arguments. |
| * @throws OperationCanceledException if the operation was canceled. |
| */ |
| public void execute(String sql, Object[] bindArgs, int connectionFlags, |
| CancellationSignal cancellationSignal) { |
| if (sql == null) { |
| throw new IllegalArgumentException("sql must not be null."); |
| } |
| |
| if (executeSpecial(sql, bindArgs, connectionFlags, cancellationSignal)) { |
| return; |
| } |
| |
| acquireConnection(sql, connectionFlags, cancellationSignal); // might throw |
| try { |
| mConnection.execute(sql, bindArgs, cancellationSignal); // might throw |
| } finally { |
| releaseConnection(); // might throw |
| } |
| } |
| |
| /** |
| * Executes a statement that returns a single <code>long</code> result. |
| * |
| * @param sql The SQL statement to execute. |
| * @param bindArgs The arguments to bind, or null if none. |
| * @param connectionFlags The connection flags to use if a connection must be |
| * acquired by this operation. Refer to {@link SQLiteConnectionPool}. |
| * @param cancellationSignal A signal to cancel the operation in progress, or null if none. |
| * @return The value of the first column in the first row of the result set |
| * as a <code>long</code>, or zero if none. |
| * |
| * @throws SQLiteException if an error occurs, such as a syntax error |
| * or invalid number of bind arguments. |
| * @throws OperationCanceledException if the operation was canceled. |
| */ |
| public long executeForLong(String sql, Object[] bindArgs, int connectionFlags, |
| CancellationSignal cancellationSignal) { |
| if (sql == null) { |
| throw new IllegalArgumentException("sql must not be null."); |
| } |
| |
| if (executeSpecial(sql, bindArgs, connectionFlags, cancellationSignal)) { |
| return 0; |
| } |
| |
| acquireConnection(sql, connectionFlags, cancellationSignal); // might throw |
| try { |
| return mConnection.executeForLong(sql, bindArgs, cancellationSignal); // might throw |
| } finally { |
| releaseConnection(); // might throw |
| } |
| } |
| |
| /** |
| * Executes a statement that returns a single {@link String} result. |
| * |
| * @param sql The SQL statement to execute. |
| * @param bindArgs The arguments to bind, or null if none. |
| * @param connectionFlags The connection flags to use if a connection must be |
| * acquired by this operation. Refer to {@link SQLiteConnectionPool}. |
| * @param cancellationSignal A signal to cancel the operation in progress, or null if none. |
| * @return The value of the first column in the first row of the result set |
| * as a <code>String</code>, or null if none. |
| * |
| * @throws SQLiteException if an error occurs, such as a syntax error |
| * or invalid number of bind arguments. |
| * @throws OperationCanceledException if the operation was canceled. |
| */ |
| public String executeForString(String sql, Object[] bindArgs, int connectionFlags, |
| CancellationSignal cancellationSignal) { |
| if (sql == null) { |
| throw new IllegalArgumentException("sql must not be null."); |
| } |
| |
| if (executeSpecial(sql, bindArgs, connectionFlags, cancellationSignal)) { |
| return null; |
| } |
| |
| acquireConnection(sql, connectionFlags, cancellationSignal); // might throw |
| try { |
| return mConnection.executeForString(sql, bindArgs, cancellationSignal); // might throw |
| } finally { |
| releaseConnection(); // might throw |
| } |
| } |
| |
| /** |
| * Executes a statement that returns a single BLOB result as a |
| * file descriptor to a shared memory region. |
| * |
| * @param sql The SQL statement to execute. |
| * @param bindArgs The arguments to bind, or null if none. |
| * @param connectionFlags The connection flags to use if a connection must be |
| * acquired by this operation. Refer to {@link SQLiteConnectionPool}. |
| * @param cancellationSignal A signal to cancel the operation in progress, or null if none. |
| * @return The file descriptor for a shared memory region that contains |
| * the value of the first column in the first row of the result set as a BLOB, |
| * or null if none. |
| * |
| * @throws SQLiteException if an error occurs, such as a syntax error |
| * or invalid number of bind arguments. |
| * @throws OperationCanceledException if the operation was canceled. |
| */ |
| public ParcelFileDescriptor executeForBlobFileDescriptor(String sql, Object[] bindArgs, |
| int connectionFlags, CancellationSignal cancellationSignal) { |
| if (sql == null) { |
| throw new IllegalArgumentException("sql must not be null."); |
| } |
| |
| if (executeSpecial(sql, bindArgs, connectionFlags, cancellationSignal)) { |
| return null; |
| } |
| |
| acquireConnection(sql, connectionFlags, cancellationSignal); // might throw |
| try { |
| return mConnection.executeForBlobFileDescriptor(sql, bindArgs, |
| cancellationSignal); // might throw |
| } finally { |
| releaseConnection(); // might throw |
| } |
| } |
| |
| /** |
| * Executes a statement that returns a count of the number of rows |
| * that were changed. Use for UPDATE or DELETE SQL statements. |
| * |
| * @param sql The SQL statement to execute. |
| * @param bindArgs The arguments to bind, or null if none. |
| * @param connectionFlags The connection flags to use if a connection must be |
| * acquired by this operation. Refer to {@link SQLiteConnectionPool}. |
| * @param cancellationSignal A signal to cancel the operation in progress, or null if none. |
| * @return The number of rows that were changed. |
| * |
| * @throws SQLiteException if an error occurs, such as a syntax error |
| * or invalid number of bind arguments. |
| * @throws OperationCanceledException if the operation was canceled. |
| */ |
| public int executeForChangedRowCount(String sql, Object[] bindArgs, int connectionFlags, |
| CancellationSignal cancellationSignal) { |
| if (sql == null) { |
| throw new IllegalArgumentException("sql must not be null."); |
| } |
| |
| if (executeSpecial(sql, bindArgs, connectionFlags, cancellationSignal)) { |
| return 0; |
| } |
| |
| acquireConnection(sql, connectionFlags, cancellationSignal); // might throw |
| try { |
| return mConnection.executeForChangedRowCount(sql, bindArgs, |
| cancellationSignal); // might throw |
| } finally { |
| releaseConnection(); // might throw |
| } |
| } |
| |
| /** |
| * Executes a statement that returns the row id of the last row inserted |
| * by the statement. Use for INSERT SQL statements. |
| * |
| * @param sql The SQL statement to execute. |
| * @param bindArgs The arguments to bind, or null if none. |
| * @param connectionFlags The connection flags to use if a connection must be |
| * acquired by this operation. Refer to {@link SQLiteConnectionPool}. |
| * @param cancellationSignal A signal to cancel the operation in progress, or null if none. |
| * @return The row id of the last row that was inserted, or 0 if none. |
| * |
| * @throws SQLiteException if an error occurs, such as a syntax error |
| * or invalid number of bind arguments. |
| * @throws OperationCanceledException if the operation was canceled. |
| */ |
| public long executeForLastInsertedRowId(String sql, Object[] bindArgs, int connectionFlags, |
| CancellationSignal cancellationSignal) { |
| if (sql == null) { |
| throw new IllegalArgumentException("sql must not be null."); |
| } |
| |
| if (executeSpecial(sql, bindArgs, connectionFlags, cancellationSignal)) { |
| return 0; |
| } |
| |
| acquireConnection(sql, connectionFlags, cancellationSignal); // might throw |
| try { |
| return mConnection.executeForLastInsertedRowId(sql, bindArgs, |
| cancellationSignal); // might throw |
| } finally { |
| releaseConnection(); // might throw |
| } |
| } |
| |
| /** |
| * Executes a statement and populates the specified {@link CursorWindow} |
| * with a range of results. Returns the number of rows that were counted |
| * during query execution. |
| * |
| * @param sql The SQL statement to execute. |
| * @param bindArgs The arguments to bind, or null if none. |
| * @param window The cursor window to clear and fill. |
| * @param startPos The start position for filling the window. |
| * @param requiredPos The position of a row that MUST be in the window. |
| * If it won't fit, then the query should discard part of what it filled |
| * so that it does. Must be greater than or equal to <code>startPos</code>. |
| * @param countAllRows True to count all rows that the query would return |
| * regagless of whether they fit in the window. |
| * @param connectionFlags The connection flags to use if a connection must be |
| * acquired by this operation. Refer to {@link SQLiteConnectionPool}. |
| * @param cancellationSignal A signal to cancel the operation in progress, or null if none. |
| * @return The number of rows that were counted during query execution. Might |
| * not be all rows in the result set unless <code>countAllRows</code> is true. |
| * |
| * @throws SQLiteException if an error occurs, such as a syntax error |
| * or invalid number of bind arguments. |
| * @throws OperationCanceledException if the operation was canceled. |
| */ |
| public int executeForCursorWindow(String sql, Object[] bindArgs, |
| CursorWindow window, int startPos, int requiredPos, boolean countAllRows, |
| int connectionFlags, CancellationSignal cancellationSignal) { |
| if (sql == null) { |
| throw new IllegalArgumentException("sql must not be null."); |
| } |
| if (window == null) { |
| throw new IllegalArgumentException("window must not be null."); |
| } |
| |
| if (executeSpecial(sql, bindArgs, connectionFlags, cancellationSignal)) { |
| window.clear(); |
| return 0; |
| } |
| |
| acquireConnection(sql, connectionFlags, cancellationSignal); // might throw |
| try { |
| return mConnection.executeForCursorWindow(sql, bindArgs, |
| window, startPos, requiredPos, countAllRows, |
| cancellationSignal); // might throw |
| } finally { |
| releaseConnection(); // might throw |
| } |
| } |
| |
| /** |
| * Performs special reinterpretation of certain SQL statements such as "BEGIN", |
| * "COMMIT" and "ROLLBACK" to ensure that transaction state invariants are |
| * maintained. |
| * |
| * This function is mainly used to support legacy apps that perform their |
| * own transactions by executing raw SQL rather than calling {@link #beginTransaction} |
| * and the like. |
| * |
| * @param sql The SQL statement to execute. |
| * @param bindArgs The arguments to bind, or null if none. |
| * @param connectionFlags The connection flags to use if a connection must be |
| * acquired by this operation. Refer to {@link SQLiteConnectionPool}. |
| * @param cancellationSignal A signal to cancel the operation in progress, or null if none. |
| * @return True if the statement was of a special form that was handled here, |
| * false otherwise. |
| * |
| * @throws SQLiteException if an error occurs, such as a syntax error |
| * or invalid number of bind arguments. |
| * @throws OperationCanceledException if the operation was canceled. |
| */ |
| private boolean executeSpecial(String sql, Object[] bindArgs, int connectionFlags, |
| CancellationSignal cancellationSignal) { |
| if (cancellationSignal != null) { |
| cancellationSignal.throwIfCanceled(); |
| } |
| |
| final int type = DatabaseUtils.getSqlStatementType(sql); |
| switch (type) { |
| case DatabaseUtils.STATEMENT_BEGIN: |
| beginTransaction(TRANSACTION_MODE_EXCLUSIVE, null, connectionFlags, |
| cancellationSignal); |
| return true; |
| |
| case DatabaseUtils.STATEMENT_COMMIT: |
| setTransactionSuccessful(); |
| endTransaction(cancellationSignal); |
| return true; |
| |
| case DatabaseUtils.STATEMENT_ABORT: |
| endTransaction(cancellationSignal); |
| return true; |
| } |
| return false; |
| } |
| |
| private void acquireConnection(String sql, int connectionFlags, |
| CancellationSignal cancellationSignal) { |
| if (mConnection == null) { |
| assert mConnectionUseCount == 0; |
| mConnection = mConnectionPool.acquireConnection(sql, connectionFlags, |
| cancellationSignal); // might throw |
| mConnectionFlags = connectionFlags; |
| } |
| mConnectionUseCount += 1; |
| } |
| |
| private void releaseConnection() { |
| assert mConnection != null; |
| assert mConnectionUseCount > 0; |
| if (--mConnectionUseCount == 0) { |
| try { |
| mConnectionPool.releaseConnection(mConnection); // might throw |
| } finally { |
| mConnection = null; |
| } |
| } |
| } |
| |
| private void throwIfNoTransaction() { |
| if (mTransactionStack == null) { |
| throw new IllegalStateException("Cannot perform this operation because " |
| + "there is no current transaction."); |
| } |
| } |
| |
| private void throwIfTransactionMarkedSuccessful() { |
| if (mTransactionStack != null && mTransactionStack.mMarkedSuccessful) { |
| throw new IllegalStateException("Cannot perform this operation because " |
| + "the transaction has already been marked successful. The only " |
| + "thing you can do now is call endTransaction()."); |
| } |
| } |
| |
| private void throwIfNestedTransaction() { |
| if (mTransactionStack == null && mTransactionStack.mParent != null) { |
| throw new IllegalStateException("Cannot perform this operation because " |
| + "a nested transaction is in progress."); |
| } |
| } |
| |
| private Transaction obtainTransaction(int mode, SQLiteTransactionListener listener) { |
| Transaction transaction = mTransactionPool; |
| if (transaction != null) { |
| mTransactionPool = transaction.mParent; |
| transaction.mParent = null; |
| transaction.mMarkedSuccessful = false; |
| transaction.mChildFailed = false; |
| } else { |
| transaction = new Transaction(); |
| } |
| transaction.mMode = mode; |
| transaction.mListener = listener; |
| return transaction; |
| } |
| |
| private void recycleTransaction(Transaction transaction) { |
| transaction.mParent = mTransactionPool; |
| transaction.mListener = null; |
| mTransactionPool = transaction; |
| } |
| |
| private static final class Transaction { |
| public Transaction mParent; |
| public int mMode; |
| public SQLiteTransactionListener mListener; |
| public boolean mMarkedSuccessful; |
| public boolean mChildFailed; |
| } |
| } |