| 1 | /** |
| 2 | * Portions Copyright (c) Meta Platforms, Inc. and affiliates. |
| 3 | * |
| 4 | * This source code is licensed under the MIT license found in the |
| 5 | * LICENSE file in the root directory of this source tree. |
| 6 | */ |
| 7 | |
| 8 | /* |
| 9 | |
| 10 | Copyright (c) 2020 Jun Wu |
| 11 | |
| 12 | Permission is hereby granted, free of charge, to any person obtaining a copy |
| 13 | of this software and associated documentation files (the "Software"), to deal |
| 14 | in the Software without restriction, including without limitation the rights |
| 15 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| 16 | copies of the Software, and to permit persons to whom the Software is |
| 17 | furnished to do so, subject to the following conditions: |
| 18 | |
| 19 | The above copyright notice and this permission notice shall be included in all |
| 20 | copies or substantial portions of the Software. |
| 21 | |
| 22 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 23 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 24 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| 25 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 26 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| 27 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| 28 | SOFTWARE. |
| 29 | |
| 30 | */ |
| 31 | |
| 32 | import type {RecordOf, ValueObject} from 'immutable'; |
| 33 | import type {LRUWithStats} from 'shared/LRU'; |
| 34 | |
| 35 | import {hash, Set as ImSet, List, Record} from 'immutable'; |
| 36 | import {cached, cachedMethod, LRU} from 'shared/LRU'; |
| 37 | import {diffLines, splitLines} from 'shared/diff'; |
| 38 | import {SelfUpdate} from 'shared/immutableExt'; |
| 39 | import {nullthrows} from 'shared/utils'; |
| 40 | import {assert} from './utils'; |
| 41 | |
| 42 | /** Operation code. */ |
| 43 | enum Op { |
| 44 | /** Unconditional jump. */ |
| 45 | J = 0, |
| 46 | /** Jump if the current rev >= operand. */ |
| 47 | JGE = 1, |
| 48 | /** Jump if the current rev < operand. */ |
| 49 | JL = 2, |
| 50 | /** Append a line. */ |
| 51 | LINE = 3, |
| 52 | /** End execution. */ |
| 53 | END = 4, |
| 54 | } |
| 55 | |
| 56 | /** J instruction. */ |
| 57 | const J = Record( |
| 58 | { |
| 59 | /** Opcode: J */ |
| 60 | op: Op.J, |
| 61 | /** Program counter (offset to jump). */ |
| 62 | pc: 0, |
| 63 | }, |
| 64 | 'J', |
| 65 | ); |
| 66 | type J = RecordOf<{ |
| 67 | op: Op.J; |
| 68 | pc: number; |
| 69 | }>; |
| 70 | |
| 71 | /** JGE instruction. */ |
| 72 | const JGE = Record( |
| 73 | { |
| 74 | /** Opcode: JGE */ |
| 75 | op: Op.JGE, |
| 76 | /** `rev` to test. */ |
| 77 | rev: 0, |
| 78 | /** Program counter (offset to jump). */ |
| 79 | pc: 0, |
| 80 | }, |
| 81 | 'JGE', |
| 82 | ); |
| 83 | type JGE = RecordOf<{ |
| 84 | op: Op.JGE; |
| 85 | rev: Rev; |
| 86 | pc: number; |
| 87 | }>; |
| 88 | |
| 89 | /** JL instruction. */ |
| 90 | const JL = Record( |
| 91 | { |
| 92 | /** Opcode: JL */ |
| 93 | op: Op.JL, |
| 94 | /** `rev` to test. */ |
| 95 | rev: 0, |
| 96 | /** Program counter (offset to jump). */ |
| 97 | pc: 0, |
| 98 | }, |
| 99 | 'JL', |
| 100 | ); |
| 101 | type JL = RecordOf<{ |
| 102 | op: Op.JL; |
| 103 | rev: Rev; |
| 104 | pc: number; |
| 105 | }>; |
| 106 | |
| 107 | /** LINE instruction. */ |
| 108 | const LINE = Record( |
| 109 | { |
| 110 | /** Opcode: LINE */ |
| 111 | op: Op.LINE, |
| 112 | /** `rev` to test. */ |
| 113 | rev: 0, |
| 114 | /** Line content. Includes EOL. */ |
| 115 | data: '', |
| 116 | }, |
| 117 | 'LINE', |
| 118 | ); |
| 119 | type LINE = RecordOf<{ |
| 120 | op: Op.LINE; |
| 121 | rev: Rev; |
| 122 | data: string; |
| 123 | }>; |
| 124 | |
| 125 | /** END instruction. */ |
| 126 | const END = Record( |
| 127 | { |
| 128 | /** Opcode: END */ |
| 129 | op: Op.END, |
| 130 | }, |
| 131 | 'END', |
| 132 | ); |
| 133 | type END = RecordOf<{ |
| 134 | op: Op.END; |
| 135 | }>; |
| 136 | |
| 137 | /** Program counter (offset to instructions). */ |
| 138 | type Pc = number; |
| 139 | |
| 140 | /** Revision number. Usually starts from 1. Larger number means newer versions. |
| 141 | * |
| 142 | * For advanced use-cases, this can be a floating number. For example, absorb |
| 143 | * might use rev 2.5 between rev2 and rev 3, indicating the chunk is currently |
| 144 | * absorbed into rev 2 (by checking out 2.999), while still preserving the rev |
| 145 | * 2 losslessly (by checking out 2, instead of 2.999). `absorb` might also use |
| 146 | * different fractional part to "tag" the chunk so they can be treated |
| 147 | * differently. For example, there are 2 chunk edits in the working copy a.txt, |
| 148 | * absorb might use `1 / 1024` to represent the first edit, and `2 / 1024` for |
| 149 | * the second chunk edit so those edits can be moved (remapped) separately. |
| 150 | * absorb might also split a chunk edit into multiple edits so the individual |
| 151 | * lines can be moved separately. |
| 152 | */ |
| 153 | type Rev = number; |
| 154 | |
| 155 | /** Index of a line. Starts from 0. */ |
| 156 | type LineIdx = number; |
| 157 | |
| 158 | /** Instruction. */ |
| 159 | type Inst = J | END | JGE | JL | LINE; |
| 160 | |
| 161 | /** Information about a line. Internal (`lines`) result of `LineLog.checkOut`. */ |
| 162 | interface LineInfo { |
| 163 | /** Line content. Includes EOL. */ |
| 164 | data: string; |
| 165 | /** Added by the given rev. */ |
| 166 | rev: Rev; |
| 167 | /** Produced by the instruction at the given offset. */ |
| 168 | pc: Pc; |
| 169 | /** |
| 170 | * Whether the line is deleted. |
| 171 | * This is always `false` if `checkOut(rev, None)`. |
| 172 | * It might be `true` when checking out a range of revisions |
| 173 | * (aka. `start` passed to `checkOut` is not `null`). |
| 174 | */ |
| 175 | deleted: boolean; |
| 176 | } |
| 177 | |
| 178 | /** A "flatten" line. Result of `LineLog.flatten()`. */ |
| 179 | type FlattenLineProps = { |
| 180 | /** The line is present in the given revisions. */ |
| 181 | revs: ImSet<Rev>; |
| 182 | /** Content of the line, including `\n`. */ |
| 183 | data: string; |
| 184 | }; |
| 185 | const FlattenLine = Record<FlattenLineProps>({revs: ImSet(), data: ''}); |
| 186 | type FlattenLine = RecordOf<FlattenLineProps>; |
| 187 | |
| 188 | /** Used by visitWithInsDelStacks */ |
| 189 | type Frame = {rev: Rev; endPc: Pc}; |
| 190 | |
| 191 | /** |
| 192 | * List of instructions. |
| 193 | * |
| 194 | * This is a wrapper of `List<Inst>` for more efficient `hashCode` and `equals` |
| 195 | * calculations. The default `hashCode` from `immutable.js` scans the whole |
| 196 | * `List`. In this implementation we keep 2 internal values: hash and str. The |
| 197 | * `hash` is used for hashCode, and the `str` is an append-only string that |
| 198 | * tracks the `editChunk` and other operations to `List<Inst>` for testing |
| 199 | * equality. |
| 200 | * |
| 201 | * You might have noticed that the `str` equality might not match the |
| 202 | * `List<Inst>` equality. For example, if we remap 1 to 2, then remap 2 to 1, |
| 203 | * the `List<Inst>` is not changed, but the `str` is changed. It is okay to |
| 204 | * treat the linelogs as different in this case as we almost always immediately |
| 205 | * rebuild linelogs after a `remap`. It's important to make sure `recordText` |
| 206 | * with the same text list gets cache hit. |
| 207 | */ |
| 208 | class Code implements ValueObject { |
| 209 | constructor( |
| 210 | private instList: List<Inst> = List([END() as Inst]), |
| 211 | private __hash: Readonly<number> = 0, |
| 212 | private __valueOf: Readonly<string> = '', |
| 213 | ) {} |
| 214 | |
| 215 | getSize(): number { |
| 216 | return this.instList.size; |
| 217 | } |
| 218 | |
| 219 | get(pc: Pc): Readonly<Inst> | undefined { |
| 220 | return this.instList.get(pc); |
| 221 | } |
| 222 | |
| 223 | valueOf(): string { |
| 224 | return this.__valueOf; |
| 225 | } |
| 226 | |
| 227 | equals(other: Code): boolean { |
| 228 | return this.__valueOf === other.__valueOf; |
| 229 | } |
| 230 | |
| 231 | hashCode(): number { |
| 232 | return this.__hash; |
| 233 | } |
| 234 | |
| 235 | /** |
| 236 | * Dump instructions in a human readable format. Useful for debugging. |
| 237 | * Note: This exposes internal details which might change in the future. |
| 238 | */ |
| 239 | describeHumanReadableInstructions(): string[] { |
| 240 | return this.instList.map((inst, i) => `${i}: ${describeInst(inst)}`).toArray(); |
| 241 | } |
| 242 | |
| 243 | /** |
| 244 | * Dump lines with ASCII annotated insertions and deletions stacks. |
| 245 | */ |
| 246 | describeHumanReadableInsDelStacks(): string[] { |
| 247 | // 1st Pass: Figure out the max stack depth, line length for padding. |
| 248 | let maxInsStackDepth = 0; |
| 249 | let maxDelStackDepth = 0; |
| 250 | let maxLineLength = 'Insert (rev: 1000)'.length; |
| 251 | this.visitWithInsDelStacks((insStack, delStack) => { |
| 252 | return { |
| 253 | onStackPush: () => { |
| 254 | maxInsStackDepth = Math.max(maxInsStackDepth, insStack.length + 1); |
| 255 | maxDelStackDepth = Math.max(maxDelStackDepth, delStack.length + 2); |
| 256 | }, |
| 257 | onLine: line => { |
| 258 | maxLineLength = Math.max(maxLineLength, line.data.length + 'Line: '.length); |
| 259 | }, |
| 260 | }; |
| 261 | }); |
| 262 | // 2nd Pass: Render the instructions. |
| 263 | const result: string[] = []; |
| 264 | this.visitWithInsDelStacks((insStack, delStack) => { |
| 265 | const pushLine = (data: string, leftAdjust?: number, rightAdjust?: number) => { |
| 266 | const insDepth = insStack.length - 1 + (leftAdjust ?? 0); |
| 267 | const delDepth = delStack.length + (rightAdjust ?? 0); |
| 268 | const insPad = maxInsStackDepth - insDepth; |
| 269 | const delPad = maxDelStackDepth - delDepth; |
| 270 | const left = |
| 271 | '|'.repeat(insDepth) + |
| 272 | (leftAdjust == null ? ' '.repeat(insPad + 1) : `+${'-'.repeat(insPad)}`); |
| 273 | const right = |
| 274 | (rightAdjust == null ? ' '.repeat(delPad + 1) : `${'-'.repeat(delPad)}+`) + |
| 275 | '|'.repeat(delDepth); |
| 276 | const middle = data + ' '.repeat(maxLineLength - data.length); |
| 277 | result.push(left + middle + right); |
| 278 | }; |
| 279 | return { |
| 280 | onStackPush: stack => { |
| 281 | const rev = stack.at(-1)?.rev ?? 0; |
| 282 | if (stack === insStack) { |
| 283 | // | | +------ Insert (rev x) <- this line |
| 284 | // | | | Line: .... <- following lines |
| 285 | pushLine(`Insert (rev ${rev})`, -1); |
| 286 | } else { |
| 287 | pushLine(`Delete (rev ${rev})`, undefined, -1); |
| 288 | } |
| 289 | }, |
| 290 | onStackPop: stack => { |
| 291 | if (stack === insStack) { |
| 292 | pushLine('', 0); |
| 293 | } else { |
| 294 | pushLine('', undefined, 0); |
| 295 | } |
| 296 | }, |
| 297 | onLine: line => { |
| 298 | pushLine(`Line: ${line.data.trimEnd()}`); |
| 299 | }, |
| 300 | }; |
| 301 | }); |
| 302 | return result; |
| 303 | } |
| 304 | |
| 305 | editChunk( |
| 306 | aRev: Rev, |
| 307 | a1: LineIdx, |
| 308 | a2: LineIdx, |
| 309 | bRev: Rev, |
| 310 | bLines: string[], |
| 311 | [aLines, aLinesMutable]: [LineInfo[], true] | [Readonly<LineInfo[]>, false], |
| 312 | ): Code { |
| 313 | const start = this.instList.size; |
| 314 | |
| 315 | assert(a1 <= a2, 'illegal chunk (a1 < a2)'); |
| 316 | assert(a2 <= aLines.length, 'out of bound a2 (wrong aRev?)'); |
| 317 | |
| 318 | // See also https://sapling-scm.com/docs/internals/linelog/#editing-linelog |
| 319 | // # Before # After |
| 320 | // # (pc): Instruction # (pc): Instruction |
| 321 | // : ... : ... |
| 322 | // a1Pc: <a1Inst> a1Pc: J start |
| 323 | // a1Pc+1: ... a1Pc+1: ... |
| 324 | // : ... : ... |
| 325 | // a2Pc: ... a2Pc: ... |
| 326 | // : ... : ... |
| 327 | // len: N/A start: JL brev b2Pc [1] |
| 328 | // : LINE brev b1 [1] |
| 329 | // : LINE brev b1+1 [1] |
| 330 | // : ... [1] |
| 331 | // : LINE brev b2-1 [1] |
| 332 | // b2Pc: JGE brev a2Pc [2] |
| 333 | // : <a1Inst> (moved) [3] |
| 334 | // : J a1Pc+1 [4] |
| 335 | // [1]: Only present if `bLines` is not empty. |
| 336 | // [2]: Only present if `a1 < a2`. |
| 337 | // There are 2 choices for "a2Pc": |
| 338 | // - The a2 line exactly: aLines[a2].pc |
| 339 | // - The next instruction of the "a2 -1" line: aLines[a2 - 1].pc + 1 |
| 340 | // We pick the latter to avoid overly aggressive deletion. |
| 341 | // The original C implementation might pick the former when editing |
| 342 | // the last rev for performance optimization. |
| 343 | // [3]: <a1 Inst> could be LINE or END. |
| 344 | // [4]: As an optimization, this is only present if <a1 Inst> is not END. |
| 345 | // |
| 346 | // Optimization [OPT1] to make reorder less restrictive, treat insertion |
| 347 | // (a1 == a2) at the beginning of another insertion (<a1 Inst> is after a |
| 348 | // <JL>) specially. Our goal is to avoid nested JLs. Instead of patching |
| 349 | // the a1Inst after the JL, we patch the JL (jlInst) so we can insert our |
| 350 | // new JL (for this edit) before the old JL (jlInst, being patched). |
| 351 | // Note this "JL followed by a1Inst" optimization needs to be applicable |
| 352 | // multiple times. To do that, we also move the a1Inst to right after the |
| 353 | // jlInst so the pattern "JL followed by a1Inst" can be recognized by the |
| 354 | // next editChunk to apply the same optimization. |
| 355 | // |
| 356 | // # Before # After |
| 357 | // # (pc): Instruction # (pc): Instruction |
| 358 | // : ... : ... |
| 359 | // : <jlInst> a1Pc-1: J start [*] |
| 360 | // a1Pc: <a1Inst> a1Pc: NOP (J a1Pc+1) [*] |
| 361 | // : ... : ... |
| 362 | // len: N/A start: JL brev b2Pc |
| 363 | // : (bLines) |
| 364 | // b2Pc: <jlInst> (moved) [*] |
| 365 | // : <a1Inst> (moved) |
| 366 | // : J a1Pc [*] |
| 367 | const newInstList = this.instList.withMutations(origCode => { |
| 368 | let code = origCode; |
| 369 | const a1Pc = aLines[a1].pc; |
| 370 | // If `jlInst` is set, optimization [OPT1] is in effect. |
| 371 | let jlInst = a1Pc > 0 && a1 === a2 ? code.get(a1Pc - 1) : undefined; |
| 372 | if (jlInst?.op !== Op.JL) { |
| 373 | jlInst = undefined; |
| 374 | } |
| 375 | if (bLines.length > 0) { |
| 376 | // [1] |
| 377 | const b2Pc = start + bLines.length + 1; |
| 378 | code = code.push(JL({rev: bRev, pc: b2Pc}) as Inst); |
| 379 | bLines.forEach(line => { |
| 380 | code = code.push(LINE({rev: bRev, data: line}) as Inst); |
| 381 | }); |
| 382 | assert(b2Pc === code.size, 'bug: wrong pc'); |
| 383 | } |
| 384 | if (a1 < a2) { |
| 385 | assert(jlInst === undefined, 'OPT1 requires no deletion'); |
| 386 | // [2] |
| 387 | const a2Pc = aLines[a2 - 1].pc + 1; |
| 388 | code = code.push(JGE({rev: bRev, pc: a2Pc}) as Inst); |
| 389 | } |
| 390 | if (aLinesMutable) { |
| 391 | aLines[a1] = {...aLines[a1], pc: jlInst == null ? code.size : code.size + 1}; |
| 392 | } |
| 393 | const a1Inst = nullthrows(code.get(a1Pc)); |
| 394 | if (jlInst === undefined) { |
| 395 | // [3] |
| 396 | code = code.push(a1Inst); |
| 397 | if (a1Inst.op /* LINE or END */ !== Op.END) { |
| 398 | // [4] |
| 399 | code = code.push(J({pc: a1Pc + 1}) as Inst); |
| 400 | } |
| 401 | code = code.set(a1Pc, J({pc: start}) as Inst); |
| 402 | } else { |
| 403 | code = code |
| 404 | .push(jlInst) |
| 405 | .push(a1Inst) |
| 406 | .push(J({pc: a1Pc}) as Inst) |
| 407 | .set(a1Pc - 1, J({pc: start}) as Inst) |
| 408 | .set(a1Pc, J({pc: a1Pc + 1}) as J); |
| 409 | } |
| 410 | return code; |
| 411 | }); |
| 412 | |
| 413 | if (aLinesMutable) { |
| 414 | const newLines = bLines.map((s, i) => { |
| 415 | return {data: s, rev: bRev, pc: start + 1 + i, deleted: false}; |
| 416 | }); |
| 417 | aLines.splice(a1, a2 - a1, ...newLines); |
| 418 | } |
| 419 | |
| 420 | const newValueOf = `E${aRev},${a1},${a2},${bRev},${bLines.join('')}`; |
| 421 | return this.newCode(newInstList, newValueOf); |
| 422 | } |
| 423 | |
| 424 | /** |
| 425 | * Visit (execute) instructions with the insertion and deletion stacks |
| 426 | * converted from JGE and JL instructions maintained by this function. |
| 427 | * |
| 428 | * See the comment in this function about how to turn JGE and JL to |
| 429 | * the stacks. |
| 430 | * |
| 431 | * For stacks like this: |
| 432 | * |
| 433 | * +---- Insertion (rev 1) |
| 434 | * | Line 1 |
| 435 | * | ----+ Deletion (rev 4) |
| 436 | * | Line 2 | |
| 437 | * | +-- Insertion (rev 2) | |
| 438 | * | | Line 3 | |
| 439 | * | | --+ | Deletion (rev 3) |
| 440 | * | | Line 4 | | |
| 441 | * | +-- | | |
| 442 | * | Line 5 | | |
| 443 | * | --+ | |
| 444 | * | Line 6 | |
| 445 | * | ----+ |
| 446 | * | Line 7 |
| 447 | * +---- |
| 448 | * |
| 449 | * When visiting "Line 3", the callsite will get insertion stack = |
| 450 | * [rev 1, rev 2] and deletion stack = [rev 4]. |
| 451 | * |
| 452 | * Internally, this is done by turning conditional jumps (JGE or JL) |
| 453 | * to stack pushes, pops at the JGE or JL destinations, and follow |
| 454 | * unconditional jumps (J) as usual. For more details, see the comment |
| 455 | * inside this function. |
| 456 | * |
| 457 | * This function will call `withContext` to provide the `insStack` and |
| 458 | * `delStack` context, and expect the callsite to provide handlers it |
| 459 | * is interested in. |
| 460 | * |
| 461 | * Typical use-cases include features that need to scan all (ever existed) |
| 462 | * lines like flatten() and calculateDepMap(). |
| 463 | */ |
| 464 | visitWithInsDelStacks( |
| 465 | withContext: ( |
| 466 | insStack: Readonly<Frame[]>, |
| 467 | delStack: Readonly<Frame[]>, |
| 468 | ) => { |
| 469 | /** Before stack pop or push */ |
| 470 | onPc?: (pc: number) => void; |
| 471 | /** After stack pop, before stack push */ |
| 472 | onLine?: (inst: LINE) => void; |
| 473 | /** After stack pop, before stack push */ |
| 474 | onConditionalJump?: (inst: JGE | JL) => void; |
| 475 | /** After stack push */ |
| 476 | onStackPush?: (stack: Readonly<Frame[]>) => void; |
| 477 | /** After stack pop */ |
| 478 | onStackPop?: (stack: Readonly<Frame[]>) => void; |
| 479 | }, |
| 480 | ) { |
| 481 | // How does it work? First, insertions and deletions in linelog form |
| 482 | // tree structures. For example: |
| 483 | // |
| 484 | // +---- Insertion (rev 1) |
| 485 | // | Line 1 |
| 486 | // | ----+ Deletion (rev 4) |
| 487 | // | Line 2 | |
| 488 | // | +-- Insertion (rev 2) | |
| 489 | // | | Line 3 | |
| 490 | // | | --+ | Deletion (rev 3) |
| 491 | // | | Line 4 | | |
| 492 | // | +-- | | |
| 493 | // | Line 5 | | |
| 494 | // | --+ | |
| 495 | // | Line 6 | |
| 496 | // | ----+ |
| 497 | // | Line 7 |
| 498 | // +---- |
| 499 | // |
| 500 | // Note interleaved insertions do not happen. For example, this does not |
| 501 | // happen: |
| 502 | // |
| 503 | // +---- Insertion (rev 1) |
| 504 | // | Line 1 |
| 505 | // | +-- Insertion (rev 2) |
| 506 | // | | Line 2 |
| 507 | // +-|-- |
| 508 | // | Line 3 |
| 509 | // +-- |
| 510 | // |
| 511 | // Similarly, interleaved deletions do not happen. However, insertions |
| 512 | // might interleave with deletions, as shown above. |
| 513 | // |
| 514 | // Let's look at how this is done at the instruction level. First, look at |
| 515 | // the instructions generated by editChunk: |
| 516 | // |
| 517 | // a2Pc: ... |
| 518 | // ... |
| 519 | // start: JL brev b2Pc |
| 520 | // ... |
| 521 | // b2Pc: JGE brev a2Pc |
| 522 | // : <a1 Inst> |
| 523 | // end: J a1Pc+1 |
| 524 | // |
| 525 | // JL is used for insertion, JGE is used for deletion. We then use them to |
| 526 | // manipulate the insStack and delStack: |
| 527 | // |
| 528 | // insStack: |
| 529 | // |
| 530 | // - On "start: JL brev b2Pc": |
| 531 | // Do not follow the JL jump. |
| 532 | // Push {rev, b2Pc} to insStack. |
| 533 | // - When pc is b2Pc, pop insStack. |
| 534 | // |
| 535 | // delStack: |
| 536 | // |
| 537 | // - On "b2Pc: JGE brev a2Pc": |
| 538 | // Do not follow the JGE jump. |
| 539 | // Push {rev, a2Pc} to delStack. |
| 540 | // - When pc is a2Pc, pop delStack. |
| 541 | // |
| 542 | // You might have noticed that we don't use the revs in LINE instructions |
| 543 | // at all. This is because that LINE rev always matches its JL rev in this |
| 544 | // implementation. In other words, the "rev" in LINE instruction is |
| 545 | // redundant as it can be inferred from JL, with an insStack. Note in the |
| 546 | // original C implementation of LineLog the LINE rev can be different from |
| 547 | // the JL rev, to deal with merges while maintaining a linear history. |
| 548 | const insStack: Frame[] = [{rev: 0, endPc: -1}]; |
| 549 | const delStack: Frame[] = []; |
| 550 | const {onPc, onLine, onConditionalJump, onStackPush, onStackPop} = withContext( |
| 551 | insStack, |
| 552 | delStack, |
| 553 | ); |
| 554 | let pc = 0; |
| 555 | let patience = this.getSize() * 2; |
| 556 | while (patience > 0) { |
| 557 | onPc?.(pc); |
| 558 | if (insStack.at(-1)?.endPc === pc) { |
| 559 | insStack.pop(); |
| 560 | onStackPop?.(insStack); |
| 561 | } |
| 562 | if (delStack.at(-1)?.endPc === pc) { |
| 563 | delStack.pop(); |
| 564 | onStackPop?.(delStack); |
| 565 | } |
| 566 | const code = nullthrows(this.get(pc)); |
| 567 | switch (code.op) { |
| 568 | case Op.LINE: |
| 569 | onLine?.(code); |
| 570 | pc += 1; |
| 571 | break; |
| 572 | case Op.END: |
| 573 | patience = -1; |
| 574 | break; |
| 575 | case Op.J: |
| 576 | pc = code.pc; |
| 577 | break; |
| 578 | case Op.JGE: |
| 579 | onConditionalJump?.(code); |
| 580 | delStack.push({rev: code.rev, endPc: code.pc}); |
| 581 | onStackPush?.(delStack); |
| 582 | pc += 1; |
| 583 | break; |
| 584 | case Op.JL: |
| 585 | onConditionalJump?.(code); |
| 586 | insStack.push({rev: code.rev, endPc: code.pc}); |
| 587 | onStackPush?.(insStack); |
| 588 | pc += 1; |
| 589 | break; |
| 590 | default: |
| 591 | assert(false, 'bug: unknown code'); |
| 592 | } |
| 593 | patience -= 1; |
| 594 | } |
| 595 | if (patience === 0) { |
| 596 | assert(false, 'bug: code does not end in time'); |
| 597 | } |
| 598 | } |
| 599 | |
| 600 | remapRevs(revMapOrFunc: Map<Rev, Rev> | ((rev: Rev) => Rev)): [Code, Rev] { |
| 601 | let revMap = new Map<Rev, Rev>(); |
| 602 | if (typeof revMapOrFunc === 'function') { |
| 603 | this.instList.forEach(inst => { |
| 604 | const rev = (inst as RecordOf<{rev?: number}>).rev; |
| 605 | if (rev != null && !revMap.has(rev)) { |
| 606 | revMap.set(rev, revMapOrFunc(rev)); |
| 607 | } |
| 608 | }); |
| 609 | } else { |
| 610 | revMap = revMapOrFunc; |
| 611 | } |
| 612 | |
| 613 | const valueOfString = [...revMap.entries()].toString(); |
| 614 | return this.rewriteInsts((c, _pc) => { |
| 615 | if (c.op === Op.JGE || c.op === Op.JL || c.op === Op.LINE) { |
| 616 | const newRev = revMap.get(c.rev) ?? c.rev; |
| 617 | // TypeScript cannot prove `c` has `rev`. Ideally it can figure out it automatically. |
| 618 | return (c as RecordOf<{rev: number}>).set('rev', newRev) as Inst; |
| 619 | } |
| 620 | return c; |
| 621 | }, valueOfString); |
| 622 | } |
| 623 | |
| 624 | /** |
| 625 | * Rewrite all instructions. Returns [newCode, newMaxRev]. |
| 626 | * `valueOfString` sets a unique string that represents the change for equal tests. |
| 627 | */ |
| 628 | rewriteInsts(func: (inst: Inst, pc: Pc) => Inst, valueOfString?: string): [Code, Rev] { |
| 629 | let newMaxRev = 0; |
| 630 | const newInstList = this.instList |
| 631 | .map((inst, pc) => { |
| 632 | const newInst = func(inst, pc); |
| 633 | const newRev = (newInst as RecordOf<{rev: number}>).rev; |
| 634 | if (newRev != null && newRev > newMaxRev) { |
| 635 | newMaxRev = newRev; |
| 636 | } |
| 637 | return newInst; |
| 638 | }) |
| 639 | .toList(); |
| 640 | const newValueOf = `R${valueOfString ?? func}`; |
| 641 | const newCode = this.newCode(newInstList, newValueOf); |
| 642 | return [newCode, newMaxRev]; |
| 643 | } |
| 644 | |
| 645 | /** |
| 646 | * Drop edits for revs >= the given rev. Returns [newCode, newMaxRev]. |
| 647 | */ |
| 648 | truncate(rev: Rev): [Code, Rev] { |
| 649 | const valueOfString = `TRUNC${rev}`; |
| 650 | return this.rewriteInsts((inst, pc) => { |
| 651 | if (inst.op === Op.JGE || inst.op === Op.LINE) { |
| 652 | if (inst.rev >= rev) { |
| 653 | // NOP. |
| 654 | return J({pc: pc + 1}) as Inst; |
| 655 | } |
| 656 | } else if (inst.op === Op.JL) { |
| 657 | if (inst.rev >= rev) { |
| 658 | // Unconditional jump. |
| 659 | return J({pc: inst.pc}) as Inst; |
| 660 | } |
| 661 | } |
| 662 | return inst; |
| 663 | }, valueOfString); |
| 664 | } |
| 665 | |
| 666 | private newCode(instList: List<Inst>, newValueOf: string): Code { |
| 667 | const newStr = this.__valueOf + '\0' + newValueOf; |
| 668 | // We want bitwise operations. |
| 669 | // eslint-disable-next-line no-bitwise |
| 670 | const newHash = (this.__hash * 23 + hash(newValueOf)) & 0x7fffffff; |
| 671 | return new Code(instList, newHash, newStr); |
| 672 | } |
| 673 | } |
| 674 | |
| 675 | // Export for testing purpose. |
| 676 | export const executeCache: LRUWithStats = new LRU(1000); |
| 677 | const calculateDepCache: LRUWithStats = new LRU(1000); |
| 678 | const flattenCache: LRUWithStats = new LRU(1000); |
| 679 | const recordTextCache: LRUWithStats = new LRU(1000); |
| 680 | |
| 681 | type LineLogProps = { |
| 682 | /** Core state: instructions. The array index type is `Pc`. */ |
| 683 | code: Code; |
| 684 | /** Maximum rev tracked (inclusive). */ |
| 685 | maxRev: Rev; |
| 686 | }; |
| 687 | |
| 688 | const LineLogRecord = Record<LineLogProps>({ |
| 689 | code: new Code(), |
| 690 | maxRev: 0 as Rev, |
| 691 | }); |
| 692 | type LineLogRecord = RecordOf<LineLogProps>; |
| 693 | |
| 694 | /** |
| 695 | * `LineLog` is a data structure that tracks linear changes to a single text |
| 696 | * file. Conceptually similar to a list of texts like `string[]`, with extra |
| 697 | * features suitable for stack editing: |
| 698 | * - Calculate the "blame" of the text of a given version efficiently. |
| 699 | * - Edit lines or trunks in a past version, and affect future versions. |
| 700 | * - List all lines that ever existed with each line annotated, like |
| 701 | * a unified diff, but for all versions, not just 2 versions. |
| 702 | * |
| 703 | * Internally, `LineLog` is a byte-code interpreter that runs a program to |
| 704 | * emit lines. Changes are done by patching in new byte-codes. There are |
| 705 | * no traditional text patch involved. No operations would cause merge |
| 706 | * conflicts. See https://sapling-scm.com/docs/internals/linelog for more |
| 707 | * details. |
| 708 | * |
| 709 | * This implementation of `LineLog` uses immutable patterns. |
| 710 | * Write operations return new `LineLog`s. |
| 711 | */ |
| 712 | class LineLog extends SelfUpdate<LineLogRecord> { |
| 713 | constructor(props?: {code?: Code; maxRev?: Rev}) { |
| 714 | const record = LineLogRecord(props); |
| 715 | super(record); |
| 716 | } |
| 717 | |
| 718 | get maxRev(): Rev { |
| 719 | return this.inner.maxRev; |
| 720 | } |
| 721 | |
| 722 | get code(): Code { |
| 723 | return this.inner.code; |
| 724 | } |
| 725 | |
| 726 | /** |
| 727 | * Edit chunk. Replace line `a1` (inclusive) to `a2` (exclusive) in rev |
| 728 | * `aRev` with `bLines`. `bLines` are considered introduced by `bRev`. |
| 729 | * If `bLines` is empty, the edit is a deletion. If `a1` equals to `a2`, |
| 730 | * the edit is an insertion. Otherwise, the edit is a modification. |
| 731 | * |
| 732 | * While this function does not cause conflicts or error out, not all |
| 733 | * editings make practical sense. The callsite might want to do some |
| 734 | * extra checks to ensure the edit is meaningful. |
| 735 | * |
| 736 | * `aLinesCache` is optional. If provided, then `editChunk` will skip a |
| 737 | * `checkOutLines` call and modify `aLinesCache` *in place* to reflect |
| 738 | * the edit. It is used by `recordText`. |
| 739 | * |
| 740 | * If `blockShift` is `true`, consider shifting the insertion lines |
| 741 | * to relax dependency for easier reordering. Check the comments |
| 742 | * in this function for details. |
| 743 | */ |
| 744 | editChunk( |
| 745 | aRev: Rev, |
| 746 | a1: LineIdx, |
| 747 | a2: LineIdx, |
| 748 | bRev: Rev, |
| 749 | bLines: string[], |
| 750 | aLinesCache?: LineInfo[], |
| 751 | blockShift = true, |
| 752 | ): LineLog { |
| 753 | const aLinesMutable = aLinesCache != null; |
| 754 | const aLinesInfo: [LineInfo[], true] | [Readonly<LineInfo[]>, false] = aLinesMutable |
| 755 | ? [aLinesCache, true] |
| 756 | : [this.checkOutLines(aRev), false]; |
| 757 | |
| 758 | const bLen = bLines.length; |
| 759 | if (a1 === a2 && bLen > 0 && blockShift) { |
| 760 | // Attempt to shift the insertion chunk so the start of insertion aligns |
| 761 | // with another "start insertion". This might trigger the [OPT1] |
| 762 | // optimization in `code.editChunk`, avoid nested insertions and enable |
| 763 | // more flexible reordering. |
| 764 | // |
| 765 | // For example, we might get "Insert (rev 3)" below that forces a nested |
| 766 | // insertion block. However, if we shift the block and use the |
| 767 | // "Alternative Insert (rev 3)", we can use the [OPT1] optimization. |
| 768 | // |
| 769 | // +----Insert (rev 1) |
| 770 | // | Line: function a () { |
| 771 | // | Line: return 'a'; |
| 772 | // | Line: } |
| 773 | // +---- |
| 774 | // +----Insert (rev 2) |
| 775 | // | ----+ Alternative Insert (rev 3) |
| 776 | // | Line: | |
| 777 | // |+---Insert (rev 3) | |
| 778 | // || Line: function b () { | |
| 779 | // || Line: return 'b'; | |
| 780 | // || Line: } | |
| 781 | // || ----+ |
| 782 | // || Line: |
| 783 | // |+--- |
| 784 | // | Line: function c () { |
| 785 | // | Line: return 'c'; |
| 786 | // | Line: } |
| 787 | // +---- |
| 788 | // |
| 789 | // Block shifting works if the surrounding lines match, see: |
| 790 | // |
| 791 | // A A |
| 792 | // B +-------+ |
| 793 | // +-------+ is equivalent to | B | |
| 794 | // | block | === shift up ==> | block | |
| 795 | // | B | <== shift down === +-------+ |
| 796 | // +-------+ B |
| 797 | // C C |
| 798 | |
| 799 | const aLines: Readonly<LineInfo[]> = aLinesInfo[0]; |
| 800 | const canUseOpt1 = (a: LineIdx): boolean => { |
| 801 | const pc = aLines.at(a)?.pc; |
| 802 | // Check [OPT1] for how this works. |
| 803 | return pc != null && pc > 0 && this.code.get(pc - 1)?.op === Op.JL; |
| 804 | }; |
| 805 | if (!canUseOpt1(a1)) { |
| 806 | const considerShift = (step: 'down' | 'up'): LineLog | undefined => { |
| 807 | let ai = a1; |
| 808 | let lines = [...bLines]; |
| 809 | // Limit overhead. |
| 810 | const threshold = 10; |
| 811 | for (let i = 0; i < threshold; ++i) { |
| 812 | // Out of range? |
| 813 | if (step === 'up' ? ai === 0 : ai === aLines.length - 1) { |
| 814 | return undefined; |
| 815 | } |
| 816 | // Surrounding lines match? |
| 817 | const [aIdx, bIdx] = step === 'up' ? [ai - 1, -1] : [ai, 0]; |
| 818 | const aData = aLines.at(aIdx)?.data; |
| 819 | const bData = lines.at(bIdx); |
| 820 | if (bData !== aData || bData == null) { |
| 821 | return undefined; |
| 822 | } |
| 823 | // Shift. |
| 824 | lines = |
| 825 | step === 'up' ? [bData].concat(lines.slice(0, -1)) : lines.slice(1).concat([bData]); |
| 826 | ai += step === 'up' ? -1 : 1; |
| 827 | // Good enough? |
| 828 | if (canUseOpt1(ai)) { |
| 829 | return this.editChunk(aRev, ai, ai, bRev, lines, aLinesCache, false); |
| 830 | } |
| 831 | } |
| 832 | }; |
| 833 | const maybeShifted = considerShift('up') ?? considerShift('down'); |
| 834 | if (maybeShifted != null) { |
| 835 | return maybeShifted; |
| 836 | } |
| 837 | } |
| 838 | } |
| 839 | const newCode = this.code.editChunk(aRev, a1, a2, bRev, bLines, aLinesInfo); |
| 840 | const newMaxRev = Math.max(bRev, this.maxRev); |
| 841 | return new LineLog({code: newCode, maxRev: newMaxRev}); |
| 842 | } |
| 843 | |
| 844 | /** |
| 845 | * Rewrite `rev` to `mapping[rev] ?? rev`. |
| 846 | * This can be useful for reordering, folding, or insertion. |
| 847 | * |
| 848 | * Note: There are no checks about whether the reordering is |
| 849 | * meaningful or not. The callsite is responsible to perform |
| 850 | * a dependency check and avoid troublesome reorders like |
| 851 | * moving a change to before its dependency. |
| 852 | */ |
| 853 | remapRevs(revMap: Map<Rev, Rev> | ((rev: Rev) => Rev)): LineLog { |
| 854 | const [newCode, newMaxRev] = this.code.remapRevs(revMap); |
| 855 | return new LineLog({code: newCode, maxRev: newMaxRev}); |
| 856 | } |
| 857 | |
| 858 | /** |
| 859 | * Truncate linelog. Drop rev (inclusive) and higher revs. |
| 860 | */ |
| 861 | truncate(rev: Rev): LineLog { |
| 862 | const [newCode, newMaxRev] = this.code.truncate(rev); |
| 863 | return new LineLog({code: newCode, maxRev: newMaxRev}); |
| 864 | } |
| 865 | |
| 866 | /** |
| 867 | * Calculate the dependencies of revisions. |
| 868 | * For example, `{5: [3, 1]}` means rev 5 depends on rev 3 and rev 1. |
| 869 | * |
| 870 | * Based on LineLog, which could be different from traditional textual |
| 871 | * context-line dependencies. LineLog dependency is to prevent |
| 872 | * "malformed cases" [1] when following the dependency to `remapRevs`. |
| 873 | * Practically, LineLog might allow reorder cases that would be |
| 874 | * disallowed by traditional context-line dependencies. See tests |
| 875 | * for examples. |
| 876 | * |
| 877 | * [1]: Malformed cases are when nested blocks (insertions or deletions) |
| 878 | * might be skipped incorrectly. The outer block says "skip" and the |
| 879 | * inner block does not want to "skip" but is still skipped since it |
| 880 | * is skipped altogether with the outer block. See also section 0.4 |
| 881 | * and 0.5 in D3628440. |
| 882 | */ |
| 883 | public calculateDepMap = cachedMethod(this.calculateDepMapImpl, {cache: calculateDepCache}); |
| 884 | |
| 885 | private calculateDepMapImpl(): Readonly<Map<Rev, Set<Rev>>> { |
| 886 | // With the insertion and deletion stacks (see explanation in |
| 887 | // visitWithInsDelStacks), when we see a new insertion block, or deletion |
| 888 | // block, we add two dependencies: |
| 889 | // - The inner rev depends on the outer insertion rev. |
| 890 | // - The outer deletion rev (if present) depends on the inner rev. |
| 891 | // |
| 892 | // Let's look at how this is done at the instruction level. |
| 893 | // the instructions generated by editChunk: |
| 894 | // |
| 895 | // a2Pc: ... |
| 896 | // ... |
| 897 | // start: JL brev b2Pc |
| 898 | // ... |
| 899 | // b2Pc: JGE brev a2Pc |
| 900 | // : <a1 Inst> |
| 901 | // end: J a1Pc+1 |
| 902 | // |
| 903 | // JL is used for insertion, JGE is used for deletion. We then use them to |
| 904 | // manipulate the insStack and delStack: |
| 905 | // |
| 906 | // insStack: |
| 907 | // |
| 908 | // - On "start: JL brev b2Pc": |
| 909 | // Do not follow the JL jump. (by visitWithInsDelStacks) |
| 910 | // Mark brev as dependent on the outer insertion. |
| 911 | // Mark the outer deletion as dependent on this brev. |
| 912 | // Push {rev, b2Pc} to insStack. (by visitWithInsDelStacks) |
| 913 | // - When pc is b2Pc, pop insStack. (by visitWithInsDelStacks) |
| 914 | // |
| 915 | // delStack: |
| 916 | // |
| 917 | // - On "b2Pc: JGE brev a2Pc": |
| 918 | // Do not follow the JGE jump. (by visitWithInsDelStacks) |
| 919 | // Mark brev as dependent on the outer insertion. |
| 920 | // Mark the outer deletion as dependent on this brev. |
| 921 | // Push {rev, a2Pc} to delStack. (by visitWithInsDelStacks) |
| 922 | // - When pc is a2Pc, pop delStack. (by visitWithInsDelStacks) |
| 923 | const depMap = new Map<Rev, Set<Rev>>(); |
| 924 | const addDep = (child: Rev, parent: Rev) => { |
| 925 | if (child > parent) { |
| 926 | if (!depMap.has(child)) { |
| 927 | depMap.set(child, new Set()); |
| 928 | } |
| 929 | depMap.get(child)?.add(parent); |
| 930 | } |
| 931 | }; |
| 932 | this.code.visitWithInsDelStacks((insStack, delStack) => { |
| 933 | const markDep = (rev: Rev) => { |
| 934 | const ins = insStack.at(-1); |
| 935 | if (ins !== undefined) { |
| 936 | addDep(rev, ins.rev); |
| 937 | } |
| 938 | const del = delStack.at(-1); |
| 939 | if (del !== undefined) { |
| 940 | addDep(del.rev, rev); |
| 941 | } |
| 942 | }; |
| 943 | return { |
| 944 | onConditionalJump: inst => markDep(inst.rev), |
| 945 | }; |
| 946 | }); |
| 947 | return depMap; |
| 948 | } |
| 949 | |
| 950 | /** |
| 951 | * Interpret the bytecodes with the given revision range. |
| 952 | * Used by `checkOut`. |
| 953 | */ |
| 954 | public execute = cachedMethod(this.executeImpl, {cache: executeCache}); |
| 955 | |
| 956 | private executeImpl( |
| 957 | startRev: Rev, |
| 958 | endRev: Rev = startRev, |
| 959 | present?: {[pc: number]: boolean}, |
| 960 | ): Readonly<LineInfo[]> { |
| 961 | const rev = endRev; |
| 962 | const lines: LineInfo[] = []; |
| 963 | let pc = 0; |
| 964 | let patience = this.code.getSize() * 2; |
| 965 | const deleted = present == null ? () => false : (pc: Pc) => !present[pc]; |
| 966 | while (patience > 0) { |
| 967 | const code = nullthrows(this.code.get(pc)); |
| 968 | switch (code.op) { |
| 969 | case Op.END: |
| 970 | lines.push({data: '', rev: 0, pc, deleted: deleted(pc)}); |
| 971 | patience = -1; |
| 972 | break; |
| 973 | case Op.LINE: |
| 974 | lines.push({data: code.data, rev: code.rev, pc, deleted: deleted(pc)}); |
| 975 | pc += 1; |
| 976 | break; |
| 977 | case Op.J: |
| 978 | pc = code.pc; |
| 979 | break; |
| 980 | case Op.JGE: |
| 981 | if (startRev >= code.rev) { |
| 982 | pc = code.pc; |
| 983 | } else { |
| 984 | pc += 1; |
| 985 | } |
| 986 | break; |
| 987 | case Op.JL: |
| 988 | if (rev < code.rev) { |
| 989 | pc = code.pc; |
| 990 | } else { |
| 991 | pc += 1; |
| 992 | } |
| 993 | break; |
| 994 | default: |
| 995 | assert(false, 'bug: unknown code'); |
| 996 | } |
| 997 | patience -= 1; |
| 998 | } |
| 999 | if (patience === 0) { |
| 1000 | assert(false, 'bug: code does not end in time'); |
| 1001 | } |
| 1002 | return lines; |
| 1003 | } |
| 1004 | |
| 1005 | /** |
| 1006 | * Flatten lines. Each returned line is associated with a set |
| 1007 | * of `Rev`s, meaning that line is present in those `Rev`s. |
| 1008 | * |
| 1009 | * The returned lines can be useful to figure out file contents |
| 1010 | * after reordering, folding commits. It can also provide a view |
| 1011 | * similar to `absorb -e FILE` to edit all versions of a file in |
| 1012 | * a single view. |
| 1013 | */ |
| 1014 | public flatten = cachedMethod(this.flattenImpl, {cache: flattenCache}); |
| 1015 | |
| 1016 | private flattenImpl(): List<FlattenLine> { |
| 1017 | const result: FlattenLine[] = []; |
| 1018 | |
| 1019 | // See the comments in calculateDepMap for what the stacks mean. |
| 1020 | // |
| 1021 | // The flatten algorithm works as follows: |
| 1022 | // - For each line, we got an insRev (insStack.at(-1).rev), and a |
| 1023 | // delRev (delStack.at(-1)?.rev ?? maxRev + 1), meaning the rev |
| 1024 | // attached to the innermost insertion or deletion blocks, |
| 1025 | // respectively. |
| 1026 | // - That line is then present in insRev .. delRev (exclusive) revs. |
| 1027 | // |
| 1028 | // This works because: |
| 1029 | // - The blocks are nested in order: |
| 1030 | // - For nested insertions, the nested one must have a larger rev, and |
| 1031 | // lines inside the nested block are only present starting from the |
| 1032 | // larger rev. |
| 1033 | // - For nested deletions, the nested one must have a smaller rev, and |
| 1034 | // lines inside the nested block are considered as deleted by the |
| 1035 | // smaller rev. |
| 1036 | // - For interleaved insertion and deletions, insertion rev and deletion |
| 1037 | // rev are tracked separately so their calculations are independent |
| 1038 | // from each other. |
| 1039 | // - Linelog tracks linear history, so (insRev, delRev) can be converted to |
| 1040 | // a Set<Rev>. |
| 1041 | this.code.visitWithInsDelStacks((insStack, delStack) => { |
| 1042 | const maxDelRev = this.maxRev + 1; |
| 1043 | const getCurrentRevs = (): ImSet<Rev> => { |
| 1044 | const insRev = insStack.at(-1)?.rev ?? 0; |
| 1045 | const delRev = delStack.at(-1)?.rev ?? maxDelRev; |
| 1046 | return revRangeToSet(insRev, delRev); |
| 1047 | }; |
| 1048 | let currentRevs = getCurrentRevs(); |
| 1049 | return { |
| 1050 | onStackPush: () => { |
| 1051 | currentRevs = getCurrentRevs(); |
| 1052 | }, |
| 1053 | onStackPop: () => { |
| 1054 | currentRevs = getCurrentRevs(); |
| 1055 | }, |
| 1056 | onLine: ({data}) => { |
| 1057 | result.push(FlattenLine({data, revs: currentRevs})); |
| 1058 | }, |
| 1059 | }; |
| 1060 | }); |
| 1061 | return List(result); |
| 1062 | } |
| 1063 | |
| 1064 | /** |
| 1065 | * Checkout the lines of the given revision `rev`. |
| 1066 | * |
| 1067 | * If `start` is not `null`, checkout a revision range. For example, |
| 1068 | * if `start` is 0, and `rev` is `this.maxRev`, `this.lines` will |
| 1069 | * include all lines ever existed in all revisions. |
| 1070 | * |
| 1071 | * @returns Content of the specified revision. |
| 1072 | */ |
| 1073 | public checkOutLines(rev: Rev, start: Rev | null = null): Readonly<LineInfo[]> { |
| 1074 | // eslint-disable-next-line no-param-reassign |
| 1075 | rev = Math.min(rev, this.maxRev); |
| 1076 | let lines = this.execute(rev); |
| 1077 | if (start !== null) { |
| 1078 | // Checkout a range, including deleted revs. |
| 1079 | const present: {[key: number]: boolean} = {}; |
| 1080 | lines.forEach(l => { |
| 1081 | present[l.pc] = true; |
| 1082 | }); |
| 1083 | |
| 1084 | // Go through all lines again. But do not skip chunks. |
| 1085 | lines = this.execute(start, rev, present); |
| 1086 | } |
| 1087 | return lines; |
| 1088 | } |
| 1089 | |
| 1090 | /** Checkout the content of the given rev. */ |
| 1091 | public checkOut(rev: Rev): string { |
| 1092 | const lines = this.checkOutLines(rev); |
| 1093 | const content = lines.map(l => l.data).join(''); |
| 1094 | return content; |
| 1095 | } |
| 1096 | |
| 1097 | /** |
| 1098 | * Edit LineLog to match the content of `text`. |
| 1099 | * This might affect `rev`s that are >= `rev` in the stack. |
| 1100 | * Previous revisions won't be affected. |
| 1101 | * |
| 1102 | * @param text Content to match. |
| 1103 | * @param rev Revision to to edit (in-place). If not set, append a new revision. |
| 1104 | * @returns A new `LineLog` with the change. |
| 1105 | */ |
| 1106 | public recordText = cachedMethod(this.recordTextImpl, {cache: recordTextCache}); |
| 1107 | |
| 1108 | private recordTextImpl(text: string, rev: Rev | null = null): LineLog { |
| 1109 | // rev to edit from, and rev to match 'text'. |
| 1110 | const [aRev, bRev] = rev != null ? [rev, rev] : [this.maxRev, this.maxRev + 1]; |
| 1111 | const b = text; |
| 1112 | |
| 1113 | const aLineInfos = [...this.checkOutLines(aRev)]; |
| 1114 | const bLines = splitLines(b); |
| 1115 | const aLines = aLineInfos.map(l => l.data); |
| 1116 | aLines.pop(); // Drop the last END empty line. |
| 1117 | const blocks = diffLines(aLines, bLines); |
| 1118 | // eslint-disable-next-line @typescript-eslint/no-this-alias |
| 1119 | let log: LineLog = this; |
| 1120 | |
| 1121 | blocks.reverse().forEach(([a1, a2, b1, b2]) => { |
| 1122 | log = log.editChunk(aRev, a1, a2, bRev, bLines.slice(b1, b2), aLineInfos); |
| 1123 | }); |
| 1124 | |
| 1125 | // This is needed in case editChunk is not called (no difference). |
| 1126 | const newMaxRev = Math.max(bRev, log.maxRev); |
| 1127 | |
| 1128 | // Populate cache for checking out bRev. |
| 1129 | const newLog = new LineLog({code: log.code, maxRev: newMaxRev}); |
| 1130 | executeCache.set(List([newLog, bRev]), aLineInfos); |
| 1131 | |
| 1132 | return newLog; |
| 1133 | } |
| 1134 | } |
| 1135 | |
| 1136 | /** Turn (3, 6) to Set([3, 4, 5]). */ |
| 1137 | const revRangeToSet = cached( |
| 1138 | (startRev, endRev: Rev): ImSet<Rev> => { |
| 1139 | const result: Rev[] = []; |
| 1140 | for (let rev = startRev; rev < endRev; rev++) { |
| 1141 | result.push(rev); |
| 1142 | } |
| 1143 | return ImSet(result); |
| 1144 | }, |
| 1145 | {cacheSize: 1000}, |
| 1146 | ); |
| 1147 | |
| 1148 | function describeInst(inst: Inst): string { |
| 1149 | switch (inst.op) { |
| 1150 | case Op.J: |
| 1151 | return `J ${inst.pc}`; |
| 1152 | case Op.JGE: |
| 1153 | return `JGE ${inst.rev} ${inst.pc}`; |
| 1154 | case Op.JL: |
| 1155 | return `JL ${inst.rev} ${inst.pc}`; |
| 1156 | case Op.LINE: |
| 1157 | return `LINE ${inst.rev} ${JSON.stringify(inst.data.trimEnd())}`; |
| 1158 | case Op.END: |
| 1159 | return 'END'; |
| 1160 | } |
| 1161 | } |
| 1162 | |
| 1163 | export {FlattenLine, LineLog}; |
| 1164 | export type {LineIdx, LineInfo, Rev}; |
| 1165 | |