Dianne Hackborn | 3aa49b6 | 2013-04-26 16:39:17 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2013 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package android.content; |
| 18 | |
| 19 | import android.os.Parcel; |
| 20 | import android.os.Parcelable; |
| 21 | import android.os.ParcelableParcel; |
| 22 | import android.text.TextUtils; |
| 23 | |
| 24 | import java.util.ArrayList; |
| 25 | import java.util.HashMap; |
| 26 | |
| 27 | /** |
| 28 | * Top-level class for managing and interacting with the global undo state for |
| 29 | * a document or application. This class supports both undo and redo and has |
| 30 | * helpers for merging undoable operations together as they are performed. |
| 31 | * |
| 32 | * <p>A single undoable operation is represented by {@link UndoOperation} which |
| 33 | * apps implement to define their undo/redo behavior. The UndoManager keeps |
| 34 | * a stack of undo states; each state can have one or more undo operations |
| 35 | * inside of it.</p> |
| 36 | * |
| 37 | * <p>Updates to the stack must be done inside of a {@link #beginUpdate}/{@link #endUpdate()} |
| 38 | * pair. During this time you can add new operations to the stack with |
| 39 | * {@link #addOperation}, retrieve and modify existing operations with |
| 40 | * {@link #getLastOperation}, control the label shown to the user for this operation |
| 41 | * with {@link #setUndoLabel} and {@link #suggestUndoLabel}, etc.</p> |
| 42 | * |
| 43 | * <p>Every {link UndoOperation} is associated with an {@link UndoOwner}, which identifies |
| 44 | * the data it belongs to. The owner is used to indicate how operations are dependent |
| 45 | * on each other -- operations with the same owner are dependent on others with the |
| 46 | * same owner. For example, you may have a document with multiple embedded objects. If the |
| 47 | * document itself and each embedded object use different owners, then you |
| 48 | * can provide undo semantics appropriate to the user's context: while within |
| 49 | * an embedded object, only edits to that object are seen and the user can |
| 50 | * undo/redo them without needing to impact edits in other objects; while |
| 51 | * within the larger document, all edits can be seen and the user must |
| 52 | * undo/redo them as a single stream.</p> |
| 53 | */ |
| 54 | public class UndoManager { |
| 55 | private final HashMap<String, UndoOwner> mOwners = new HashMap<String, UndoOwner>(); |
| 56 | private final ArrayList<UndoState> mUndos = new ArrayList<UndoState>(); |
| 57 | private final ArrayList<UndoState> mRedos = new ArrayList<UndoState>(); |
| 58 | private int mUpdateCount; |
| 59 | private int mHistorySize = 20; |
| 60 | private UndoState mWorking; |
| 61 | private int mCommitId = 1; |
| 62 | private boolean mInUndo; |
| 63 | private boolean mMerged; |
| 64 | |
| 65 | private int mStateSeq; |
| 66 | private int mNextSavedIdx; |
| 67 | private UndoOwner[] mStateOwners; |
| 68 | |
| 69 | /** |
| 70 | * Never merge with the last undo state. |
| 71 | */ |
| 72 | public static final int MERGE_MODE_NONE = 0; |
| 73 | |
| 74 | /** |
| 75 | * Allow merge with the last undo state only if it contains |
| 76 | * operations with the caller's owner. |
| 77 | */ |
| 78 | public static final int MERGE_MODE_UNIQUE = 1; |
| 79 | |
| 80 | /** |
| 81 | * Always allow merge with the last undo state, if possible. |
| 82 | */ |
| 83 | public static final int MERGE_MODE_ANY = 2; |
| 84 | |
| 85 | public UndoOwner getOwner(String tag, Object data) { |
| 86 | if (tag == null) { |
| 87 | throw new NullPointerException("tag can't be null"); |
| 88 | } |
| 89 | if (data == null) { |
| 90 | throw new NullPointerException("data can't be null"); |
| 91 | } |
| 92 | UndoOwner owner = mOwners.get(tag); |
| 93 | if (owner != null) { |
| 94 | if (owner.mData != data) { |
| 95 | if (owner.mData != null) { |
| 96 | throw new IllegalStateException("Owner " + owner + " already exists with data " |
| 97 | + owner.mData + " but giving different data " + data); |
| 98 | } |
| 99 | owner.mData = data; |
| 100 | } |
| 101 | return owner; |
| 102 | } |
| 103 | |
| 104 | owner = new UndoOwner(tag); |
| 105 | owner.mManager = this; |
| 106 | owner.mData = data; |
| 107 | mOwners.put(tag, owner); |
| 108 | return owner; |
| 109 | } |
| 110 | |
| 111 | void removeOwner(UndoOwner owner) { |
| 112 | // XXX need to figure out how to prune. |
| 113 | if (false) { |
| 114 | mOwners.remove(owner.mTag); |
| 115 | owner.mManager = null; |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | /** |
| 120 | * Flatten the current undo state into a Parcelable object, which can later be restored |
| 121 | * with {@link #restoreInstanceState(android.os.Parcelable)}. |
| 122 | */ |
| 123 | public Parcelable saveInstanceState() { |
| 124 | if (mUpdateCount > 0) { |
| 125 | throw new IllegalStateException("Can't save state while updating"); |
| 126 | } |
| 127 | ParcelableParcel pp = new ParcelableParcel(getClass().getClassLoader()); |
| 128 | Parcel p = pp.getParcel(); |
| 129 | mStateSeq++; |
| 130 | if (mStateSeq <= 0) { |
| 131 | mStateSeq = 0; |
| 132 | } |
| 133 | mNextSavedIdx = 0; |
| 134 | p.writeInt(mHistorySize); |
| 135 | p.writeInt(mOwners.size()); |
| 136 | // XXX eventually we need to be smart here about limiting the |
| 137 | // number of undo states we write to not exceed X bytes. |
| 138 | int i = mUndos.size(); |
| 139 | while (i > 0) { |
| 140 | p.writeInt(1); |
| 141 | i--; |
| 142 | mUndos.get(i).writeToParcel(p); |
| 143 | } |
| 144 | i = mRedos.size(); |
| 145 | p.writeInt(i); |
| 146 | while (i > 0) { |
| 147 | p.writeInt(2); |
| 148 | i--; |
| 149 | mRedos.get(i).writeToParcel(p); |
| 150 | } |
| 151 | p.writeInt(0); |
| 152 | return pp; |
| 153 | } |
| 154 | |
| 155 | void saveOwner(UndoOwner owner, Parcel out) { |
| 156 | if (owner.mStateSeq == mStateSeq) { |
| 157 | out.writeInt(owner.mSavedIdx); |
| 158 | } else { |
| 159 | owner.mStateSeq = mStateSeq; |
| 160 | owner.mSavedIdx = mNextSavedIdx; |
| 161 | out.writeInt(owner.mSavedIdx); |
| 162 | out.writeString(owner.mTag); |
| 163 | mNextSavedIdx++; |
| 164 | } |
| 165 | } |
| 166 | |
| 167 | /** |
| 168 | * Restore an undo state previously created with {@link #saveInstanceState()}. This will |
| 169 | * restore the UndoManager's state to almost exactly what it was at the point it had |
| 170 | * been previously saved; the only information not restored is the data object |
| 171 | * associated with each {@link UndoOwner}, which requires separate calls to |
| 172 | * {@link #getOwner(String, Object)} to re-associate the owner with its data. |
| 173 | */ |
| 174 | public void restoreInstanceState(Parcelable state) { |
| 175 | if (mUpdateCount > 0) { |
| 176 | throw new IllegalStateException("Can't save state while updating"); |
| 177 | } |
| 178 | forgetUndos(null, -1); |
| 179 | forgetRedos(null, -1); |
| 180 | ParcelableParcel pp = (ParcelableParcel)state; |
| 181 | Parcel p = pp.getParcel(); |
| 182 | mHistorySize = p.readInt(); |
| 183 | mStateOwners = new UndoOwner[p.readInt()]; |
| 184 | |
| 185 | int stype; |
| 186 | while ((stype=p.readInt()) != 0) { |
| 187 | UndoState ustate = new UndoState(this, p, pp.getClassLoader()); |
| 188 | if (stype == 1) { |
| 189 | mUndos.add(0, ustate); |
| 190 | } else { |
| 191 | mRedos.add(0, ustate); |
| 192 | } |
| 193 | } |
| 194 | } |
| 195 | |
| 196 | UndoOwner restoreOwner(Parcel in) { |
| 197 | int idx = in.readInt(); |
| 198 | UndoOwner owner = mStateOwners[idx]; |
| 199 | if (owner == null) { |
| 200 | String tag = in.readString(); |
| 201 | owner = new UndoOwner(tag); |
| 202 | mStateOwners[idx] = owner; |
| 203 | mOwners.put(tag, owner); |
| 204 | } |
| 205 | return owner; |
| 206 | } |
| 207 | |
| 208 | /** |
| 209 | * Set the maximum number of undo states that will be retained. |
| 210 | */ |
| 211 | public void setHistorySize(int size) { |
| 212 | mHistorySize = size; |
| 213 | if (mHistorySize >= 0 && countUndos(null) > mHistorySize) { |
| 214 | forgetUndos(null, countUndos(null) - mHistorySize); |
| 215 | } |
| 216 | } |
| 217 | |
| 218 | /** |
| 219 | * Return the current maximum number of undo states. |
| 220 | */ |
| 221 | public int getHistorySize() { |
| 222 | return mHistorySize; |
| 223 | } |
| 224 | |
| 225 | /** |
| 226 | * Perform undo of last/top <var>count</var> undo states. The states impacted |
| 227 | * by this can be limited through <var>owners</var>. |
| 228 | * @param owners Optional set of owners that should be impacted. If null, all |
| 229 | * undo states will be visible and available for undo. If non-null, only those |
| 230 | * states that contain one of the owners specified here will be visible. |
| 231 | * @param count Number of undo states to pop. |
| 232 | * @return Returns the number of undo states that were actually popped. |
| 233 | */ |
| 234 | public int undo(UndoOwner[] owners, int count) { |
| 235 | if (mWorking != null) { |
| 236 | throw new IllegalStateException("Can't be called during an update"); |
| 237 | } |
| 238 | |
| 239 | int num = 0; |
| 240 | int i = -1; |
| 241 | |
| 242 | mInUndo = true; |
| 243 | |
| 244 | UndoState us = getTopUndo(null); |
| 245 | if (us != null) { |
| 246 | us.makeExecuted(); |
| 247 | } |
| 248 | |
| 249 | while (count > 0 && (i=findPrevState(mUndos, owners, i)) >= 0) { |
| 250 | UndoState state = mUndos.remove(i); |
| 251 | state.undo(); |
| 252 | mRedos.add(state); |
| 253 | count--; |
| 254 | num++; |
| 255 | } |
| 256 | |
| 257 | mInUndo = false; |
| 258 | |
| 259 | return num; |
| 260 | } |
| 261 | |
| 262 | /** |
| 263 | * Perform redo of last/top <var>count</var> undo states in the transient redo stack. |
| 264 | * The states impacted by this can be limited through <var>owners</var>. |
| 265 | * @param owners Optional set of owners that should be impacted. If null, all |
| 266 | * undo states will be visible and available for undo. If non-null, only those |
| 267 | * states that contain one of the owners specified here will be visible. |
| 268 | * @param count Number of undo states to pop. |
| 269 | * @return Returns the number of undo states that were actually redone. |
| 270 | */ |
| 271 | public int redo(UndoOwner[] owners, int count) { |
| 272 | if (mWorking != null) { |
| 273 | throw new IllegalStateException("Can't be called during an update"); |
| 274 | } |
| 275 | |
| 276 | int num = 0; |
| 277 | int i = -1; |
| 278 | |
| 279 | mInUndo = true; |
| 280 | |
| 281 | while (count > 0 && (i=findPrevState(mRedos, owners, i)) >= 0) { |
| 282 | UndoState state = mRedos.remove(i); |
| 283 | state.redo(); |
| 284 | mUndos.add(state); |
| 285 | count--; |
| 286 | num++; |
| 287 | } |
| 288 | |
| 289 | mInUndo = false; |
| 290 | |
| 291 | return num; |
| 292 | } |
| 293 | |
| 294 | /** |
| 295 | * Returns true if we are currently inside of an undo/redo operation. This is |
| 296 | * useful for editors to know whether they should be generating new undo state |
| 297 | * when they see edit operations happening. |
| 298 | */ |
| 299 | public boolean isInUndo() { |
| 300 | return mInUndo; |
| 301 | } |
| 302 | |
| 303 | public int forgetUndos(UndoOwner[] owners, int count) { |
| 304 | if (count < 0) { |
| 305 | count = mUndos.size(); |
| 306 | } |
| 307 | |
| 308 | int removed = 0; |
| 309 | for (int i=0; i<mUndos.size() && removed < count; i++) { |
| 310 | UndoState state = mUndos.get(i); |
| 311 | if (count > 0 && matchOwners(state, owners)) { |
| 312 | state.destroy(); |
| 313 | mUndos.remove(i); |
| 314 | removed++; |
| 315 | } |
| 316 | } |
| 317 | |
| 318 | return removed; |
| 319 | } |
| 320 | |
| 321 | public int forgetRedos(UndoOwner[] owners, int count) { |
| 322 | if (count < 0) { |
| 323 | count = mRedos.size(); |
| 324 | } |
| 325 | |
| 326 | int removed = 0; |
| 327 | for (int i=0; i<mRedos.size() && removed < count; i++) { |
| 328 | UndoState state = mRedos.get(i); |
| 329 | if (count > 0 && matchOwners(state, owners)) { |
| 330 | state.destroy(); |
| 331 | mRedos.remove(i); |
| 332 | removed++; |
| 333 | } |
| 334 | } |
| 335 | |
| 336 | return removed; |
| 337 | } |
| 338 | |
| 339 | /** |
| 340 | * Return the number of undo states on the undo stack. |
| 341 | * @param owners If non-null, only those states containing an operation with one of |
| 342 | * the owners supplied here will be counted. |
| 343 | */ |
| 344 | public int countUndos(UndoOwner[] owners) { |
| 345 | if (owners == null) { |
| 346 | return mUndos.size(); |
| 347 | } |
| 348 | |
| 349 | int count=0; |
| 350 | int i=0; |
| 351 | while ((i=findNextState(mUndos, owners, i)) >= 0) { |
| 352 | count++; |
| 353 | i++; |
| 354 | } |
| 355 | return count; |
| 356 | } |
| 357 | |
| 358 | /** |
| 359 | * Return the number of redo states on the undo stack. |
| 360 | * @param owners If non-null, only those states containing an operation with one of |
| 361 | * the owners supplied here will be counted. |
| 362 | */ |
| 363 | public int countRedos(UndoOwner[] owners) { |
| 364 | if (owners == null) { |
| 365 | return mRedos.size(); |
| 366 | } |
| 367 | |
| 368 | int count=0; |
| 369 | int i=0; |
| 370 | while ((i=findNextState(mRedos, owners, i)) >= 0) { |
| 371 | count++; |
| 372 | i++; |
| 373 | } |
| 374 | return count; |
| 375 | } |
| 376 | |
| 377 | /** |
| 378 | * Return the user-visible label for the top undo state on the stack. |
| 379 | * @param owners If non-null, will select the top-most undo state containing an |
| 380 | * operation with one of the owners supplied here. |
| 381 | */ |
| 382 | public CharSequence getUndoLabel(UndoOwner[] owners) { |
| 383 | UndoState state = getTopUndo(owners); |
| 384 | return state != null ? state.getLabel() : null; |
| 385 | } |
| 386 | |
| 387 | /** |
| 388 | * Return the user-visible label for the top redo state on the stack. |
| 389 | * @param owners If non-null, will select the top-most undo state containing an |
| 390 | * operation with one of the owners supplied here. |
| 391 | */ |
| 392 | public CharSequence getRedoLabel(UndoOwner[] owners) { |
| 393 | UndoState state = getTopRedo(owners); |
| 394 | return state != null ? state.getLabel() : null; |
| 395 | } |
| 396 | |
| 397 | /** |
| 398 | * Start creating a new undo state. Multiple calls to this function will nest until |
| 399 | * they are all matched by a later call to {@link #endUpdate}. |
| 400 | * @param label Optional user-visible label for this new undo state. |
| 401 | */ |
| 402 | public void beginUpdate(CharSequence label) { |
| 403 | if (mInUndo) { |
| 404 | throw new IllegalStateException("Can't being update while performing undo/redo"); |
| 405 | } |
| 406 | if (mUpdateCount <= 0) { |
| 407 | createWorkingState(); |
| 408 | mMerged = false; |
| 409 | mUpdateCount = 0; |
| 410 | } |
| 411 | |
| 412 | mWorking.updateLabel(label); |
| 413 | mUpdateCount++; |
| 414 | } |
| 415 | |
| 416 | private void createWorkingState() { |
| 417 | mWorking = new UndoState(this, mCommitId++); |
| 418 | if (mCommitId < 0) { |
| 419 | mCommitId = 1; |
| 420 | } |
| 421 | } |
| 422 | |
| 423 | /** |
| 424 | * Returns true if currently inside of a {@link #beginUpdate}. |
| 425 | */ |
| 426 | public boolean isInUpdate() { |
| 427 | return mUpdateCount > 0; |
| 428 | } |
| 429 | |
| 430 | /** |
| 431 | * Forcibly set a new for the new undo state being built within a {@link #beginUpdate}. |
| 432 | * Any existing label will be replaced with this one. |
| 433 | */ |
| 434 | public void setUndoLabel(CharSequence label) { |
| 435 | if (mWorking == null) { |
| 436 | throw new IllegalStateException("Must be called during an update"); |
| 437 | } |
| 438 | mWorking.setLabel(label); |
| 439 | } |
| 440 | |
| 441 | /** |
| 442 | * Set a new for the new undo state being built within a {@link #beginUpdate}, but |
| 443 | * only if there is not a label currently set for it. |
| 444 | */ |
| 445 | public void suggestUndoLabel(CharSequence label) { |
| 446 | if (mWorking == null) { |
| 447 | throw new IllegalStateException("Must be called during an update"); |
| 448 | } |
| 449 | mWorking.updateLabel(label); |
| 450 | } |
| 451 | |
| 452 | /** |
| 453 | * Return the number of times {@link #beginUpdate} has been called without a matching |
| 454 | * {@link #endUpdate} call. |
| 455 | */ |
| 456 | public int getUpdateNestingLevel() { |
| 457 | return mUpdateCount; |
| 458 | } |
| 459 | |
| 460 | /** |
| 461 | * Check whether there is an {@link UndoOperation} in the current {@link #beginUpdate} |
| 462 | * undo state. |
| 463 | * @param owner Optional owner of the operation to look for. If null, will succeed |
| 464 | * if there is any operation; if non-null, will only succeed if there is an operation |
| 465 | * with the given owner. |
| 466 | * @return Returns true if there is a matching operation in the current undo state. |
| 467 | */ |
| 468 | public boolean hasOperation(UndoOwner owner) { |
| 469 | if (mWorking == null) { |
| 470 | throw new IllegalStateException("Must be called during an update"); |
| 471 | } |
| 472 | return mWorking.hasOperation(owner); |
| 473 | } |
| 474 | |
| 475 | /** |
| 476 | * Return the most recent {@link UndoOperation} that was added to the update. |
| 477 | * @param mergeMode May be either {@link #MERGE_MODE_NONE} or {@link #MERGE_MODE_ANY}. |
| 478 | */ |
| 479 | public UndoOperation<?> getLastOperation(int mergeMode) { |
| 480 | return getLastOperation(null, null, mergeMode); |
| 481 | } |
| 482 | |
| 483 | /** |
| 484 | * Return the most recent {@link UndoOperation} that was added to the update and |
| 485 | * has the given owner. |
| 486 | * @param owner Optional owner of last operation to retrieve. If null, the last |
| 487 | * operation regardless of owner will be retrieved; if non-null, the last operation |
| 488 | * matching the given owner will be retrieved. |
| 489 | * @param mergeMode May be either {@link #MERGE_MODE_NONE}, {@link #MERGE_MODE_UNIQUE}, |
| 490 | * or {@link #MERGE_MODE_ANY}. |
| 491 | */ |
| 492 | public UndoOperation<?> getLastOperation(UndoOwner owner, int mergeMode) { |
| 493 | return getLastOperation(null, owner, mergeMode); |
| 494 | } |
| 495 | |
| 496 | /** |
| 497 | * Return the most recent {@link UndoOperation} that was added to the update and |
| 498 | * has the given owner. |
| 499 | * @param clazz Optional class of the last operation to retrieve. If null, the |
| 500 | * last operation regardless of class will be retrieved; if non-null, the last |
| 501 | * operation whose class is the same as the given class will be retrieved. |
| 502 | * @param owner Optional owner of last operation to retrieve. If null, the last |
| 503 | * operation regardless of owner will be retrieved; if non-null, the last operation |
| 504 | * matching the given owner will be retrieved. |
| 505 | * @param mergeMode May be either {@link #MERGE_MODE_NONE}, {@link #MERGE_MODE_UNIQUE}, |
| 506 | * or {@link #MERGE_MODE_ANY}. |
| 507 | */ |
| 508 | public <T extends UndoOperation> T getLastOperation(Class<T> clazz, UndoOwner owner, |
| 509 | int mergeMode) { |
| 510 | if (mWorking == null) { |
| 511 | throw new IllegalStateException("Must be called during an update"); |
| 512 | } |
| 513 | if (mergeMode != MERGE_MODE_NONE && !mMerged && !mWorking.hasData()) { |
| 514 | UndoState state = getTopUndo(null); |
| 515 | UndoOperation<?> last; |
| 516 | if (state != null && (mergeMode == MERGE_MODE_ANY || !state.hasMultipleOwners()) |
| 517 | && state.canMerge() && (last=state.getLastOperation(clazz, owner)) != null) { |
| 518 | if (last.allowMerge()) { |
| 519 | mWorking.destroy(); |
| 520 | mWorking = state; |
| 521 | mUndos.remove(state); |
| 522 | mMerged = true; |
| 523 | return (T)last; |
| 524 | } |
| 525 | } |
| 526 | } |
| 527 | |
| 528 | return mWorking.getLastOperation(clazz, owner); |
| 529 | } |
| 530 | |
| 531 | /** |
| 532 | * Add a new UndoOperation to the current update. |
| 533 | * @param op The new operation to add. |
| 534 | * @param mergeMode May be either {@link #MERGE_MODE_NONE}, {@link #MERGE_MODE_UNIQUE}, |
| 535 | * or {@link #MERGE_MODE_ANY}. |
| 536 | */ |
| 537 | public void addOperation(UndoOperation<?> op, int mergeMode) { |
| 538 | if (mWorking == null) { |
| 539 | throw new IllegalStateException("Must be called during an update"); |
| 540 | } |
| 541 | UndoOwner owner = op.getOwner(); |
| 542 | if (owner.mManager != this) { |
| 543 | throw new IllegalArgumentException( |
| 544 | "Given operation's owner is not in this undo manager."); |
| 545 | } |
| 546 | if (mergeMode != MERGE_MODE_NONE && !mMerged && !mWorking.hasData()) { |
| 547 | UndoState state = getTopUndo(null); |
| 548 | if (state != null && (mergeMode == MERGE_MODE_ANY || !state.hasMultipleOwners()) |
| 549 | && state.canMerge() && state.hasOperation(op.getOwner())) { |
| 550 | mWorking.destroy(); |
| 551 | mWorking = state; |
| 552 | mUndos.remove(state); |
| 553 | mMerged = true; |
| 554 | } |
| 555 | } |
| 556 | mWorking.addOperation(op); |
| 557 | } |
| 558 | |
| 559 | /** |
| 560 | * Finish the creation of an undo state, matching a previous call to |
| 561 | * {@link #beginUpdate}. |
| 562 | */ |
| 563 | public void endUpdate() { |
| 564 | if (mWorking == null) { |
| 565 | throw new IllegalStateException("Must be called during an update"); |
| 566 | } |
| 567 | mUpdateCount--; |
| 568 | |
| 569 | if (mUpdateCount == 0) { |
| 570 | pushWorkingState(); |
| 571 | } |
| 572 | } |
| 573 | |
| 574 | private void pushWorkingState() { |
| 575 | int N = mUndos.size() + 1; |
| 576 | |
| 577 | if (mWorking.hasData()) { |
| 578 | mUndos.add(mWorking); |
| 579 | forgetRedos(null, -1); |
| 580 | mWorking.commit(); |
| 581 | if (N >= 2) { |
| 582 | // The state before this one can no longer be merged, ever. |
| 583 | // The only way to get back to it is for the user to perform |
| 584 | // an undo. |
| 585 | mUndos.get(N-2).makeExecuted(); |
| 586 | } |
| 587 | } else { |
| 588 | mWorking.destroy(); |
| 589 | } |
| 590 | mWorking = null; |
| 591 | |
| 592 | if (mHistorySize >= 0 && N > mHistorySize) { |
| 593 | forgetUndos(null, N - mHistorySize); |
| 594 | } |
| 595 | } |
| 596 | |
| 597 | /** |
| 598 | * Commit the last finished undo state. This undo state can no longer be |
| 599 | * modified with further {@link #MERGE_MODE_UNIQUE} or |
| 600 | * {@link #MERGE_MODE_ANY} merge modes. If called while inside of an update, |
| 601 | * this will push any changes in the current update on to the undo stack |
| 602 | * and result with a fresh undo state, behaving as if {@link #endUpdate()} |
| 603 | * had been called enough to unwind the current update, then the last state |
| 604 | * committed, and {@link #beginUpdate} called to restore the update nesting. |
| 605 | * @param owner The optional owner to determine whether to perform the commit. |
| 606 | * If this is non-null, the commit will only execute if the current top undo |
| 607 | * state contains an operation with the given owner. |
| 608 | * @return Returns an integer identifier for the committed undo state, which |
| 609 | * can later be used to try to uncommit the state to perform further edits on it. |
| 610 | */ |
| 611 | public int commitState(UndoOwner owner) { |
| 612 | if (mWorking != null && mWorking.hasData()) { |
| 613 | if (owner == null || mWorking.hasOperation(owner)) { |
| 614 | mWorking.setCanMerge(false); |
| 615 | int commitId = mWorking.getCommitId(); |
| 616 | pushWorkingState(); |
| 617 | createWorkingState(); |
| 618 | mMerged = true; |
| 619 | return commitId; |
| 620 | } |
| 621 | } else { |
| 622 | UndoState state = getTopUndo(null); |
| 623 | if (state != null && (owner == null || state.hasOperation(owner))) { |
| 624 | state.setCanMerge(false); |
| 625 | return state.getCommitId(); |
| 626 | } |
| 627 | } |
| 628 | return -1; |
| 629 | } |
| 630 | |
| 631 | /** |
| 632 | * Attempt to undo a previous call to {@link #commitState}. This will work |
| 633 | * if the undo state at the top of the stack has the given id, and has not been |
| 634 | * involved in an undo operation. Otherwise false is returned. |
| 635 | * @param commitId The identifier for the state to be uncommitted, as returned |
| 636 | * by {@link #commitState}. |
| 637 | * @param owner Optional owner that must appear in the committed state. |
| 638 | * @return Returns true if the uncommit is successful, else false. |
| 639 | */ |
| 640 | public boolean uncommitState(int commitId, UndoOwner owner) { |
| 641 | if (mWorking != null && mWorking.getCommitId() == commitId) { |
| 642 | if (owner == null || mWorking.hasOperation(owner)) { |
| 643 | return mWorking.setCanMerge(true); |
| 644 | } |
| 645 | } else { |
| 646 | UndoState state = getTopUndo(null); |
| 647 | if (state != null && (owner == null || state.hasOperation(owner))) { |
| 648 | if (state.getCommitId() == commitId) { |
| 649 | return state.setCanMerge(true); |
| 650 | } |
| 651 | } |
| 652 | } |
| 653 | return false; |
| 654 | } |
| 655 | |
| 656 | UndoState getTopUndo(UndoOwner[] owners) { |
| 657 | if (mUndos.size() <= 0) { |
| 658 | return null; |
| 659 | } |
| 660 | int i = findPrevState(mUndos, owners, -1); |
| 661 | return i >= 0 ? mUndos.get(i) : null; |
| 662 | } |
| 663 | |
| 664 | UndoState getTopRedo(UndoOwner[] owners) { |
| 665 | if (mRedos.size() <= 0) { |
| 666 | return null; |
| 667 | } |
| 668 | int i = findPrevState(mRedos, owners, -1); |
| 669 | return i >= 0 ? mRedos.get(i) : null; |
| 670 | } |
| 671 | |
| 672 | boolean matchOwners(UndoState state, UndoOwner[] owners) { |
| 673 | if (owners == null) { |
| 674 | return true; |
| 675 | } |
| 676 | for (int i=0; i<owners.length; i++) { |
| 677 | if (state.matchOwner(owners[i])) { |
| 678 | return true; |
| 679 | } |
| 680 | } |
| 681 | return false; |
| 682 | } |
| 683 | |
| 684 | int findPrevState(ArrayList<UndoState> states, UndoOwner[] owners, int from) { |
| 685 | final int N = states.size(); |
| 686 | |
| 687 | if (from == -1) { |
| 688 | from = N-1; |
| 689 | } |
| 690 | if (from >= N) { |
| 691 | return -1; |
| 692 | } |
| 693 | if (owners == null) { |
| 694 | return from; |
| 695 | } |
| 696 | |
| 697 | while (from >= 0) { |
| 698 | UndoState state = states.get(from); |
| 699 | if (matchOwners(state, owners)) { |
| 700 | return from; |
| 701 | } |
| 702 | from--; |
| 703 | } |
| 704 | |
| 705 | return -1; |
| 706 | } |
| 707 | |
| 708 | int findNextState(ArrayList<UndoState> states, UndoOwner[] owners, int from) { |
| 709 | final int N = states.size(); |
| 710 | |
| 711 | if (from < 0) { |
| 712 | from = 0; |
| 713 | } |
| 714 | if (from >= N) { |
| 715 | return -1; |
| 716 | } |
| 717 | if (owners == null) { |
| 718 | return from; |
| 719 | } |
| 720 | |
| 721 | while (from < N) { |
| 722 | UndoState state = states.get(from); |
| 723 | if (matchOwners(state, owners)) { |
| 724 | return from; |
| 725 | } |
| 726 | from++; |
| 727 | } |
| 728 | |
| 729 | return -1; |
| 730 | } |
| 731 | |
| 732 | final static class UndoState { |
| 733 | private final UndoManager mManager; |
| 734 | private final int mCommitId; |
| 735 | private final ArrayList<UndoOperation<?>> mOperations = new ArrayList<UndoOperation<?>>(); |
| 736 | private ArrayList<UndoOperation<?>> mRecent; |
| 737 | private CharSequence mLabel; |
| 738 | private boolean mCanMerge = true; |
| 739 | private boolean mExecuted; |
| 740 | |
| 741 | UndoState(UndoManager manager, int commitId) { |
| 742 | mManager = manager; |
| 743 | mCommitId = commitId; |
| 744 | } |
| 745 | |
| 746 | UndoState(UndoManager manager, Parcel p, ClassLoader loader) { |
| 747 | mManager = manager; |
| 748 | mCommitId = p.readInt(); |
| 749 | mCanMerge = p.readInt() != 0; |
| 750 | mExecuted = p.readInt() != 0; |
| 751 | mLabel = TextUtils.CHAR_SEQUENCE_CREATOR.createFromParcel(p); |
| 752 | final int N = p.readInt(); |
| 753 | for (int i=0; i<N; i++) { |
| 754 | UndoOwner owner = mManager.restoreOwner(p); |
| 755 | UndoOperation op = (UndoOperation)p.readParcelable(loader); |
| 756 | op.mOwner = owner; |
| 757 | mOperations.add(op); |
| 758 | } |
| 759 | } |
| 760 | |
| 761 | void writeToParcel(Parcel p) { |
| 762 | if (mRecent != null) { |
| 763 | throw new IllegalStateException("Can't save state before committing"); |
| 764 | } |
| 765 | p.writeInt(mCommitId); |
| 766 | p.writeInt(mCanMerge ? 1 : 0); |
| 767 | p.writeInt(mExecuted ? 1 : 0); |
| 768 | TextUtils.writeToParcel(mLabel, p, 0); |
| 769 | final int N = mOperations.size(); |
| 770 | p.writeInt(N); |
| 771 | for (int i=0; i<N; i++) { |
| 772 | UndoOperation op = mOperations.get(i); |
| 773 | mManager.saveOwner(op.mOwner, p); |
| 774 | p.writeParcelable(op, 0); |
| 775 | } |
| 776 | } |
| 777 | |
| 778 | int getCommitId() { |
| 779 | return mCommitId; |
| 780 | } |
| 781 | |
| 782 | void setLabel(CharSequence label) { |
| 783 | mLabel = label; |
| 784 | } |
| 785 | |
| 786 | void updateLabel(CharSequence label) { |
| 787 | if (mLabel != null) { |
| 788 | mLabel = label; |
| 789 | } |
| 790 | } |
| 791 | |
| 792 | CharSequence getLabel() { |
| 793 | return mLabel; |
| 794 | } |
| 795 | |
| 796 | boolean setCanMerge(boolean state) { |
| 797 | // Don't allow re-enabling of merging if state has been executed. |
| 798 | if (state && mExecuted) { |
| 799 | return false; |
| 800 | } |
| 801 | mCanMerge = state; |
| 802 | return true; |
| 803 | } |
| 804 | |
| 805 | void makeExecuted() { |
| 806 | mExecuted = true; |
| 807 | } |
| 808 | |
| 809 | boolean canMerge() { |
| 810 | return mCanMerge && !mExecuted; |
| 811 | } |
| 812 | |
| 813 | int countOperations() { |
| 814 | return mOperations.size(); |
| 815 | } |
| 816 | |
| 817 | boolean hasOperation(UndoOwner owner) { |
| 818 | final int N = mOperations.size(); |
| 819 | if (owner == null) { |
| 820 | return N != 0; |
| 821 | } |
| 822 | for (int i=0; i<N; i++) { |
| 823 | if (mOperations.get(i).getOwner() == owner) { |
| 824 | return true; |
| 825 | } |
| 826 | } |
| 827 | return false; |
| 828 | } |
| 829 | |
| 830 | boolean hasMultipleOwners() { |
| 831 | final int N = mOperations.size(); |
| 832 | if (N <= 1) { |
| 833 | return false; |
| 834 | } |
| 835 | UndoOwner owner = mOperations.get(0).getOwner(); |
| 836 | for (int i=1; i<N; i++) { |
| 837 | if (mOperations.get(i).getOwner() != owner) { |
| 838 | return true; |
| 839 | } |
| 840 | } |
| 841 | return false; |
| 842 | } |
| 843 | |
| 844 | void addOperation(UndoOperation<?> op) { |
| 845 | if (mOperations.contains(op)) { |
| 846 | throw new IllegalStateException("Already holds " + op); |
| 847 | } |
| 848 | mOperations.add(op); |
| 849 | if (mRecent == null) { |
| 850 | mRecent = new ArrayList<UndoOperation<?>>(); |
| 851 | mRecent.add(op); |
| 852 | } |
| 853 | op.mOwner.mOpCount++; |
| 854 | } |
| 855 | |
| 856 | <T extends UndoOperation> T getLastOperation(Class<T> clazz, UndoOwner owner) { |
| 857 | final int N = mOperations.size(); |
| 858 | if (clazz == null && owner == null) { |
| 859 | return N > 0 ? (T)mOperations.get(N-1) : null; |
| 860 | } |
| 861 | // First look for the top-most operation with the same owner. |
| 862 | for (int i=N-1; i>=0; i--) { |
| 863 | UndoOperation<?> op = mOperations.get(i); |
| 864 | if (owner != null && op.getOwner() != owner) { |
| 865 | continue; |
| 866 | } |
| 867 | // Return this operation if it has the same class that the caller wants. |
| 868 | // Note that we don't search deeper for the class, because we don't want |
| 869 | // to end up with a different order of operations for the same owner. |
| 870 | if (clazz != null && op.getClass() != clazz) { |
| 871 | return null; |
| 872 | } |
| 873 | return (T)op; |
| 874 | } |
| 875 | |
| 876 | return null; |
| 877 | } |
| 878 | |
| 879 | boolean matchOwner(UndoOwner owner) { |
| 880 | for (int i=mOperations.size()-1; i>=0; i--) { |
| 881 | if (mOperations.get(i).matchOwner(owner)) { |
| 882 | return true; |
| 883 | } |
| 884 | } |
| 885 | return false; |
| 886 | } |
| 887 | |
| 888 | boolean hasData() { |
| 889 | for (int i=mOperations.size()-1; i>=0; i--) { |
| 890 | if (mOperations.get(i).hasData()) { |
| 891 | return true; |
| 892 | } |
| 893 | } |
| 894 | return false; |
| 895 | } |
| 896 | |
| 897 | void commit() { |
| 898 | final int N = mRecent != null ? mRecent.size() : 0; |
| 899 | for (int i=0; i<N; i++) { |
| 900 | mRecent.get(i).commit(); |
| 901 | } |
| 902 | mRecent = null; |
| 903 | } |
| 904 | |
| 905 | void undo() { |
| 906 | for (int i=mOperations.size()-1; i>=0; i--) { |
| 907 | mOperations.get(i).undo(); |
| 908 | } |
| 909 | } |
| 910 | |
| 911 | void redo() { |
| 912 | final int N = mOperations.size(); |
| 913 | for (int i=0; i<N; i++) { |
| 914 | mOperations.get(i).redo(); |
| 915 | } |
| 916 | } |
| 917 | |
| 918 | void destroy() { |
| 919 | for (int i=mOperations.size()-1; i>=0; i--) { |
| 920 | UndoOwner owner = mOperations.get(i).mOwner; |
| 921 | owner.mOpCount--; |
| 922 | if (owner.mOpCount <= 0) { |
| 923 | if (owner.mOpCount < 0) { |
| 924 | throw new IllegalStateException("Underflow of op count on owner " + owner |
| 925 | + " in op " + mOperations.get(i)); |
| 926 | } |
| 927 | mManager.removeOwner(owner); |
| 928 | } |
| 929 | } |
| 930 | } |
| 931 | } |
| 932 | } |