J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2005 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package sun.java2d.pipe; |
| 27 | |
| 28 | import java.util.HashSet; |
| 29 | import java.util.Set; |
| 30 | import sun.awt.SunToolkit; |
| 31 | |
| 32 | /** |
| 33 | * The RenderQueue class encapsulates a RenderBuffer on which rendering |
| 34 | * operations are enqueued. Note that the RenderQueue lock must be acquired |
| 35 | * before performing any operations on the queue (e.g. enqueuing an operation |
| 36 | * or flushing the queue). A sample usage scenario follows: |
| 37 | * |
| 38 | * public void drawSomething(...) { |
| 39 | * rq.lock(); |
| 40 | * try { |
| 41 | * ctx.validate(...); |
| 42 | * rq.ensureCapacity(4); |
| 43 | * rq.getBuffer().putInt(DRAW_SOMETHING); |
| 44 | * ... |
| 45 | * } finally { |
| 46 | * rq.unlock(); |
| 47 | * } |
| 48 | * } |
| 49 | * |
| 50 | * If you are enqueuing an operation that involves 8-byte parameters (i.e. |
| 51 | * long or double values), it is imperative that you ensure proper |
| 52 | * alignment of the underlying RenderBuffer. This can be accomplished |
| 53 | * simply by providing an offset to the first 8-byte parameter in your |
| 54 | * operation to the ensureCapacityAndAlignment() method. For example: |
| 55 | * |
| 56 | * public void drawStuff(...) { |
| 57 | * rq.lock(); |
| 58 | * try { |
| 59 | * RenderBuffer buf = rq.getBuffer(); |
| 60 | * ctx.validate(...); |
| 61 | * // 28 total bytes in the operation, 12 bytes to the first long |
| 62 | * rq.ensureCapacityAndAlignment(28, 12); |
| 63 | * buf.putInt(DRAW_STUFF); |
| 64 | * buf.putInt(x).putInt(y); |
| 65 | * buf.putLong(addr1); |
| 66 | * buf.putLong(addr2); |
| 67 | * } finally { |
| 68 | * rq.unlock(); |
| 69 | * } |
| 70 | * } |
| 71 | */ |
| 72 | public abstract class RenderQueue { |
| 73 | |
| 74 | /** The size of the underlying buffer, in bytes. */ |
| 75 | private static final int BUFFER_SIZE = 32000; |
| 76 | |
| 77 | /** The underlying buffer for this queue. */ |
| 78 | protected RenderBuffer buf; |
| 79 | |
| 80 | /** |
| 81 | * A Set containing hard references to Objects that must stay alive until |
| 82 | * the queue has been completely flushed. |
| 83 | */ |
| 84 | protected Set refSet; |
| 85 | |
| 86 | protected RenderQueue() { |
| 87 | refSet = new HashSet(); |
| 88 | buf = RenderBuffer.allocate(BUFFER_SIZE); |
| 89 | } |
| 90 | |
| 91 | /** |
| 92 | * Locks the queue for read/write access. |
| 93 | */ |
| 94 | public final void lock() { |
| 95 | /* |
| 96 | * Implementation note: In theory we should have two separate locks: |
| 97 | * one lock to synchronize access to the RenderQueue, and then a |
| 98 | * separate lock (the AWT lock) that only needs to be acquired when |
| 99 | * we are about to flush the queue (using native windowing system |
| 100 | * operations). In practice it has been difficult to enforce the |
| 101 | * correct lock ordering; sometimes AWT will have already acquired |
| 102 | * the AWT lock before grabbing the RQ lock (see 6253009), while the |
| 103 | * expected order should be RQ lock and then AWT lock. Due to this |
| 104 | * issue, using two separate locks is prone to deadlocks. Therefore, |
| 105 | * to solve this issue we have decided to eliminate the separate RQ |
| 106 | * lock and instead just acquire the AWT lock here. (Someday it might |
| 107 | * be nice to go back to the old two-lock system, but that would |
| 108 | * require potentially risky changes to AWT to ensure that it never |
| 109 | * acquires the AWT lock before calling into 2D code that wants to |
| 110 | * acquire the RQ lock.) |
| 111 | */ |
| 112 | SunToolkit.awtLock(); |
| 113 | } |
| 114 | |
| 115 | /** |
| 116 | * Attempts to lock the queue. If successful, this method returns true, |
| 117 | * indicating that the caller is responsible for calling |
| 118 | * <code>unlock</code>; otherwise this method returns false. |
| 119 | */ |
| 120 | public final boolean tryLock() { |
| 121 | return SunToolkit.awtTryLock(); |
| 122 | } |
| 123 | |
| 124 | /** |
| 125 | * Unlocks the queue. |
| 126 | */ |
| 127 | public final void unlock() { |
| 128 | SunToolkit.awtUnlock(); |
| 129 | } |
| 130 | |
| 131 | /** |
| 132 | * Adds the given Object to the set of hard references, which will |
| 133 | * prevent that Object from being disposed until the queue has been |
| 134 | * flushed completely. This is useful in cases where some enqueued |
| 135 | * data could become invalid if the reference Object were garbage |
| 136 | * collected before the queue could be processed. (For example, keeping |
| 137 | * a hard reference to a FontStrike will prevent any enqueued glyph |
| 138 | * images associated with that strike from becoming invalid before the |
| 139 | * queue is flushed.) The reference set will be cleared immediately |
| 140 | * after the queue is flushed each time. |
| 141 | */ |
| 142 | public final void addReference(Object ref) { |
| 143 | refSet.add(ref); |
| 144 | } |
| 145 | |
| 146 | /** |
| 147 | * Returns the encapsulated RenderBuffer object. |
| 148 | */ |
| 149 | public final RenderBuffer getBuffer() { |
| 150 | return buf; |
| 151 | } |
| 152 | |
| 153 | /** |
| 154 | * Ensures that there will be enough room on the underlying buffer |
| 155 | * for the following operation. If the operation will not fit given |
| 156 | * the remaining space, the buffer will be flushed immediately, leaving |
| 157 | * an empty buffer for the impending operation. |
| 158 | * |
| 159 | * @param opsize size (in bytes) of the following operation |
| 160 | */ |
| 161 | public final void ensureCapacity(int opsize) { |
| 162 | if (buf.remaining() < opsize) { |
| 163 | flushNow(); |
| 164 | } |
| 165 | } |
| 166 | |
| 167 | /** |
| 168 | * Convenience method that is equivalent to calling ensureCapacity() |
| 169 | * followed by ensureAlignment(). The ensureCapacity() call allows for an |
| 170 | * extra 4 bytes of space in case the ensureAlignment() method needs to |
| 171 | * insert a NOOP token on the buffer. |
| 172 | * |
| 173 | * @param opsize size (in bytes) of the following operation |
| 174 | * @param first8ByteValueOffset offset (in bytes) from the current |
| 175 | * position to the first 8-byte value used in the following operation |
| 176 | */ |
| 177 | public final void ensureCapacityAndAlignment(int opsize, |
| 178 | int first8ByteValueOffset) |
| 179 | { |
| 180 | ensureCapacity(opsize + 4); |
| 181 | ensureAlignment(first8ByteValueOffset); |
| 182 | } |
| 183 | |
| 184 | /** |
| 185 | * Inserts a 4-byte NOOP token when necessary to ensure that all 8-byte |
| 186 | * parameters for the following operation are added to the underlying |
| 187 | * buffer with an 8-byte memory alignment. |
| 188 | * |
| 189 | * @param first8ByteValueOffset offset (in bytes) from the current |
| 190 | * position to the first 8-byte value used in the following operation |
| 191 | */ |
| 192 | public final void ensureAlignment(int first8ByteValueOffset) { |
| 193 | int first8ByteValuePosition = buf.position() + first8ByteValueOffset; |
| 194 | if ((first8ByteValuePosition & 7) != 0) { |
| 195 | buf.putInt(BufferedOpCodes.NOOP); |
| 196 | } |
| 197 | } |
| 198 | |
| 199 | /** |
| 200 | * Immediately processes each operation currently pending on the buffer. |
| 201 | * This method will block until the entire buffer has been flushed. The |
| 202 | * queue lock must be acquired before calling this method. |
| 203 | */ |
| 204 | public abstract void flushNow(); |
| 205 | |
| 206 | /** |
| 207 | * Immediately processes each operation currently pending on the buffer, |
| 208 | * and then invokes the provided task. This method will block until the |
| 209 | * entire buffer has been flushed and the provided task has been executed. |
| 210 | * The queue lock must be acquired before calling this method. |
| 211 | */ |
| 212 | public abstract void flushAndInvokeNow(Runnable task); |
| 213 | |
| 214 | /** |
| 215 | * Updates the current position of the underlying buffer, and then |
| 216 | * flushes the queue immediately. This method is useful when native code |
| 217 | * has added data to the queue and needs to flush immediately. |
| 218 | */ |
| 219 | public void flushNow(int position) { |
| 220 | buf.position(position); |
| 221 | flushNow(); |
| 222 | } |
| 223 | } |