--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/sun/java2d/pipe/RenderQueue.java Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,223 @@
+/*
+ * Copyright 2005 Sun Microsystems, Inc. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package sun.java2d.pipe;
+
+import java.util.HashSet;
+import java.util.Set;
+import sun.awt.SunToolkit;
+
+/**
+ * The RenderQueue class encapsulates a RenderBuffer on which rendering
+ * operations are enqueued. Note that the RenderQueue lock must be acquired
+ * before performing any operations on the queue (e.g. enqueuing an operation
+ * or flushing the queue). A sample usage scenario follows:
+ *
+ * public void drawSomething(...) {
+ * rq.lock();
+ * try {
+ * ctx.validate(...);
+ * rq.ensureCapacity(4);
+ * rq.getBuffer().putInt(DRAW_SOMETHING);
+ * ...
+ * } finally {
+ * rq.unlock();
+ * }
+ * }
+ *
+ * If you are enqueuing an operation that involves 8-byte parameters (i.e.
+ * long or double values), it is imperative that you ensure proper
+ * alignment of the underlying RenderBuffer. This can be accomplished
+ * simply by providing an offset to the first 8-byte parameter in your
+ * operation to the ensureCapacityAndAlignment() method. For example:
+ *
+ * public void drawStuff(...) {
+ * rq.lock();
+ * try {
+ * RenderBuffer buf = rq.getBuffer();
+ * ctx.validate(...);
+ * // 28 total bytes in the operation, 12 bytes to the first long
+ * rq.ensureCapacityAndAlignment(28, 12);
+ * buf.putInt(DRAW_STUFF);
+ * buf.putInt(x).putInt(y);
+ * buf.putLong(addr1);
+ * buf.putLong(addr2);
+ * } finally {
+ * rq.unlock();
+ * }
+ * }
+ */
+public abstract class RenderQueue {
+
+ /** The size of the underlying buffer, in bytes. */
+ private static final int BUFFER_SIZE = 32000;
+
+ /** The underlying buffer for this queue. */
+ protected RenderBuffer buf;
+
+ /**
+ * A Set containing hard references to Objects that must stay alive until
+ * the queue has been completely flushed.
+ */
+ protected Set refSet;
+
+ protected RenderQueue() {
+ refSet = new HashSet();
+ buf = RenderBuffer.allocate(BUFFER_SIZE);
+ }
+
+ /**
+ * Locks the queue for read/write access.
+ */
+ public final void lock() {
+ /*
+ * Implementation note: In theory we should have two separate locks:
+ * one lock to synchronize access to the RenderQueue, and then a
+ * separate lock (the AWT lock) that only needs to be acquired when
+ * we are about to flush the queue (using native windowing system
+ * operations). In practice it has been difficult to enforce the
+ * correct lock ordering; sometimes AWT will have already acquired
+ * the AWT lock before grabbing the RQ lock (see 6253009), while the
+ * expected order should be RQ lock and then AWT lock. Due to this
+ * issue, using two separate locks is prone to deadlocks. Therefore,
+ * to solve this issue we have decided to eliminate the separate RQ
+ * lock and instead just acquire the AWT lock here. (Someday it might
+ * be nice to go back to the old two-lock system, but that would
+ * require potentially risky changes to AWT to ensure that it never
+ * acquires the AWT lock before calling into 2D code that wants to
+ * acquire the RQ lock.)
+ */
+ SunToolkit.awtLock();
+ }
+
+ /**
+ * Attempts to lock the queue. If successful, this method returns true,
+ * indicating that the caller is responsible for calling
+ * <code>unlock</code>; otherwise this method returns false.
+ */
+ public final boolean tryLock() {
+ return SunToolkit.awtTryLock();
+ }
+
+ /**
+ * Unlocks the queue.
+ */
+ public final void unlock() {
+ SunToolkit.awtUnlock();
+ }
+
+ /**
+ * Adds the given Object to the set of hard references, which will
+ * prevent that Object from being disposed until the queue has been
+ * flushed completely. This is useful in cases where some enqueued
+ * data could become invalid if the reference Object were garbage
+ * collected before the queue could be processed. (For example, keeping
+ * a hard reference to a FontStrike will prevent any enqueued glyph
+ * images associated with that strike from becoming invalid before the
+ * queue is flushed.) The reference set will be cleared immediately
+ * after the queue is flushed each time.
+ */
+ public final void addReference(Object ref) {
+ refSet.add(ref);
+ }
+
+ /**
+ * Returns the encapsulated RenderBuffer object.
+ */
+ public final RenderBuffer getBuffer() {
+ return buf;
+ }
+
+ /**
+ * Ensures that there will be enough room on the underlying buffer
+ * for the following operation. If the operation will not fit given
+ * the remaining space, the buffer will be flushed immediately, leaving
+ * an empty buffer for the impending operation.
+ *
+ * @param opsize size (in bytes) of the following operation
+ */
+ public final void ensureCapacity(int opsize) {
+ if (buf.remaining() < opsize) {
+ flushNow();
+ }
+ }
+
+ /**
+ * Convenience method that is equivalent to calling ensureCapacity()
+ * followed by ensureAlignment(). The ensureCapacity() call allows for an
+ * extra 4 bytes of space in case the ensureAlignment() method needs to
+ * insert a NOOP token on the buffer.
+ *
+ * @param opsize size (in bytes) of the following operation
+ * @param first8ByteValueOffset offset (in bytes) from the current
+ * position to the first 8-byte value used in the following operation
+ */
+ public final void ensureCapacityAndAlignment(int opsize,
+ int first8ByteValueOffset)
+ {
+ ensureCapacity(opsize + 4);
+ ensureAlignment(first8ByteValueOffset);
+ }
+
+ /**
+ * Inserts a 4-byte NOOP token when necessary to ensure that all 8-byte
+ * parameters for the following operation are added to the underlying
+ * buffer with an 8-byte memory alignment.
+ *
+ * @param first8ByteValueOffset offset (in bytes) from the current
+ * position to the first 8-byte value used in the following operation
+ */
+ public final void ensureAlignment(int first8ByteValueOffset) {
+ int first8ByteValuePosition = buf.position() + first8ByteValueOffset;
+ if ((first8ByteValuePosition & 7) != 0) {
+ buf.putInt(BufferedOpCodes.NOOP);
+ }
+ }
+
+ /**
+ * Immediately processes each operation currently pending on the buffer.
+ * This method will block until the entire buffer has been flushed. The
+ * queue lock must be acquired before calling this method.
+ */
+ public abstract void flushNow();
+
+ /**
+ * Immediately processes each operation currently pending on the buffer,
+ * and then invokes the provided task. This method will block until the
+ * entire buffer has been flushed and the provided task has been executed.
+ * The queue lock must be acquired before calling this method.
+ */
+ public abstract void flushAndInvokeNow(Runnable task);
+
+ /**
+ * Updates the current position of the underlying buffer, and then
+ * flushes the queue immediately. This method is useful when native code
+ * has added data to the queue and needs to flush immediately.
+ */
+ public void flushNow(int position) {
+ buf.position(position);
+ flushNow();
+ }
+}