js/src/jsatom.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
   2  *
   3  * ***** BEGIN LICENSE BLOCK *****
   4  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   5  *
   6  * The contents of this file are subject to the Mozilla Public License Version
   7  * 1.1 (the "License"); you may not use this file except in compliance with
   8  * the License. You may obtain a copy of the License at
   9  * http://www.mozilla.org/MPL/
  10  *
  11  * Software distributed under the License is distributed on an "AS IS" basis,
  12  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  13  * for the specific language governing rights and limitations under the
  14  * License.
  15  *
  16  * The Original Code is Mozilla Communicator client code, released
  17  * March 31, 1998.
  18  *
  19  * The Initial Developer of the Original Code is
  20  * Netscape Communications Corporation.
  21  * Portions created by the Initial Developer are Copyright (C) 1998
  22  * the Initial Developer. All Rights Reserved.
  23  *
  24  * Contributor(s):
  25  *
  26  * Alternatively, the contents of this file may be used under the terms of
  27  * either of the GNU General Public License Version 2 or later (the "GPL"),
  28  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  29  * in which case the provisions of the GPL or the LGPL are applicable instead
  30  * of those above. If you wish to allow use of your version of this file only
  31  * under the terms of either the GPL or the LGPL, and not to allow others to
  32  * use your version of this file under the terms of the MPL, indicate your
  33  * decision by deleting the provisions above and replace them with the notice
  34  * and other provisions required by the GPL or the LGPL. If you do not delete
  35  * the provisions above, a recipient may use your version of this file under
  36  * the terms of any one of the MPL, the GPL or the LGPL.
  37  *
  38  * ***** END LICENSE BLOCK ***** */
  39
  40 /*
  41  * JS atom table.
  42  */
  43 #include <stdlib.h>
  44 #include <string.h>
  45 #include "jstypes.h"
  46 #include "jsstdint.h"
  47 #include "jsutil.h" /* Added by JSIFY */
  48 #include "jshash.h" /* Added by JSIFY */
  49 #include "jsprf.h"
  50 #include "jsapi.h"
  51 #include "jsatom.h"
  52 #include "jsbit.h"
  53 #include "jscntxt.h"
  54 #include "jsgc.h"
  55 #include "jslock.h"
  56 #include "jsnum.h"
  57 #include "jsparse.h"
  58 #include "jsscan.h"
  59 #include "jsstr.h"
  60 #include "jsversion.h"
  61 #include "jsstrinlines.h"
  62
  63 using namespace js;
  64
  65 /*
  66  * ATOM_HASH assumes that JSHashNumber is 32-bit even on 64-bit systems.
  67  */
  68 JS_STATIC_ASSERT(sizeof(JSHashNumber) == 4);
  69 JS_STATIC_ASSERT(sizeof(JSAtom *) == JS_BYTES_PER_WORD);
  70
  71 /*
  72  * Start and limit offsets for atom pointers in JSAtomState must be aligned
  73  * on the word boundary.
  74  */
  75 JS_STATIC_ASSERT(ATOM_OFFSET_START % sizeof(JSAtom *) == 0);
  76 JS_STATIC_ASSERT(ATOM_OFFSET_LIMIT % sizeof(JSAtom *) == 0);
  77
  78 /*
  79  * JS_BOOLEAN_STR and JS_TYPE_STR assume that boolean names starts from the
  80  * index 1 and type name starts from the index 1+2 atoms in JSAtomState.
  81  */
  82 JS_STATIC_ASSERT(1 * sizeof(JSAtom *) ==
  83                  offsetof(JSAtomState, booleanAtoms) - ATOM_OFFSET_START);
  84 JS_STATIC_ASSERT((1 + 2) * sizeof(JSAtom *) ==
  85                  offsetof(JSAtomState, typeAtoms) - ATOM_OFFSET_START);
  86
  87 const char *
  88 js_AtomToPrintableString(JSContext *cx, JSAtom *atom)
  89 {
  90     return js_ValueToPrintableString(cx, ATOM_KEY(atom));
  91 }
  92
  93 #define JS_PROTO(name,code,init) const char js_##name##_str[] = #name;
  94 #include "jsproto.tbl"
  95 #undef JS_PROTO
  96
  97 /*
  98  * String constants for common atoms defined in JSAtomState starting from
  99  * JSAtomState.emptyAtom until JSAtomState.lazy.
 100  *
 101  * The elements of the array after the first empty string define strings
 102  * corresponding to the two boolean literals, false and true, followed by the
 103  * JSType enumerators from jspubtd.h starting with "undefined" for JSTYPE_VOID
 104  * (which is special-value 2) and continuing as initialized below. The static
 105  * asserts check these relations.
 106  */
 107 JS_STATIC_ASSERT(JSTYPE_LIMIT == 8);
 108 JS_STATIC_ASSERT(JSTYPE_VOID == 0);
 109
 110 const char *const js_common_atom_names[] = {
 111     "",                         /* emptyAtom                    */
 112     js_false_str,               /* booleanAtoms[0]              */
 113     js_true_str,                /* booleanAtoms[1]              */
 114     js_undefined_str,           /* typeAtoms[JSTYPE_VOID]       */
 115     js_object_str,              /* typeAtoms[JSTYPE_OBJECT]     */
 116     js_function_str,            /* typeAtoms[JSTYPE_FUNCTION]   */
 117     "string",                   /* typeAtoms[JSTYPE_STRING]     */
 118     "number",                   /* typeAtoms[JSTYPE_NUMBER]     */
 119     "boolean",                  /* typeAtoms[JSTYPE_BOOLEAN]    */
 120     js_null_str,                /* typeAtoms[JSTYPE_NULL]       */
 121     "xml",                      /* typeAtoms[JSTYPE_XML]        */
 122     js_null_str,                /* nullAtom                     */
 123
 124 #define JS_PROTO(name,code,init) js_##name##_str,
 125 #include "jsproto.tbl"
 126 #undef JS_PROTO
 127
 128     js_anonymous_str,           /* anonymousAtom                */
 129     js_apply_str,               /* applyAtom                    */
 130     js_arguments_str,           /* argumentsAtom                */
 131     js_arity_str,               /* arityAtom                    */
 132     js_call_str,                /* callAtom                     */
 133     js_callee_str,              /* calleeAtom                   */
 134     js_caller_str,              /* callerAtom                   */
 135     js_class_prototype_str,     /* classPrototypeAtom           */
 136     js_constructor_str,         /* constructorAtom              */
 137     js_each_str,                /* eachAtom                     */
 138     js_eval_str,                /* evalAtom                     */
 139     js_fileName_str,            /* fileNameAtom                 */
 140     js_get_str,                 /* getAtom                      */
 141     js_index_str,               /* indexAtom                    */
 142     js_input_str,               /* inputAtom                    */
 143     js_iterator_str,            /* iteratorAtom                 */
 144     js_length_str,              /* lengthAtom                   */
 145     js_lineNumber_str,          /* lineNumberAtom               */
 146     js_message_str,             /* messageAtom                  */
 147     js_name_str,                /* nameAtom                     */
 148     js_next_str,                /* nextAtom                     */
 149     js_noSuchMethod_str,        /* noSuchMethodAtom             */
 150     js_proto_str,               /* protoAtom                    */
 151     js_set_str,                 /* setAtom                      */
 152     js_stack_str,               /* stackAtom                    */
 153     js_toLocaleString_str,      /* toLocaleStringAtom           */
 154     js_toSource_str,            /* toSourceAtom                 */
 155     js_toString_str,            /* toStringAtom                 */
 156     js_valueOf_str,             /* valueOfAtom                  */
 157     js_toJSON_str,              /* toJSONAtom                   */
 158     "(void 0)",                 /* void0Atom                    */
 159     js_enumerable_str,          /* enumerableAtom               */
 160     js_configurable_str,        /* configurableAtom             */
 161     js_writable_str,            /* writableAtom                 */
 162     js_value_str,               /* valueAtom                    */
 163     "use strict",               /* useStrictAtom                */
 164
 165 #if JS_HAS_XML_SUPPORT
 166     js_etago_str,               /* etagoAtom                    */
 167     js_namespace_str,           /* namespaceAtom                */
 168     js_ptagc_str,               /* ptagcAtom                    */
 169     js_qualifier_str,           /* qualifierAtom                */
 170     js_space_str,               /* spaceAtom                    */
 171     js_stago_str,               /* stagoAtom                    */
 172     js_star_str,                /* starAtom                     */
 173     js_starQualifier_str,       /* starQualifierAtom            */
 174     js_tagc_str,                /* tagcAtom                     */
 175     js_xml_str,                 /* xmlAtom                      */
 176 #endif
 177
 178 #ifdef NARCISSUS
 179     js___call___str,            /* __call__Atom                 */
 180     js___construct___str,       /* __construct__Atom            */
 181     js___hasInstance___str,     /* __hasInstance__Atom          */
 182     js_ExecutionContext_str,    /* ExecutionContextAtom         */
 183     js_current_str,             /* currentAtom                  */
 184 #endif
 185 };
 186
 187 JS_STATIC_ASSERT(JS_ARRAY_LENGTH(js_common_atom_names) * sizeof(JSAtom *) ==
 188                  LAZY_ATOM_OFFSET_START - ATOM_OFFSET_START);
 189
 190 /*
 191  * Interpreter macros called by the trace recorder assume common atom indexes
 192  * fit in one byte of immediate operand.
 193  */
 194 JS_STATIC_ASSERT(JS_ARRAY_LENGTH(js_common_atom_names) < 256);
 195
 196 const size_t js_common_atom_count = JS_ARRAY_LENGTH(js_common_atom_names);
 197
 198 const char js_anonymous_str[]       = "anonymous";
 199 const char js_apply_str[]           = "apply";
 200 const char js_arguments_str[]       = "arguments";
 201 const char js_arity_str[]           = "arity";
 202 const char js_call_str[]            = "call";
 203 const char js_callee_str[]          = "callee";
 204 const char js_caller_str[]          = "caller";
 205 const char js_class_prototype_str[] = "prototype";
 206 const char js_constructor_str[]     = "constructor";
 207 const char js_each_str[]            = "each";
 208 const char js_eval_str[]            = "eval";
 209 const char js_fileName_str[]        = "fileName";
 210 const char js_get_str[]             = "get";
 211 const char js_getter_str[]          = "getter";
 212 const char js_index_str[]           = "index";
 213 const char js_input_str[]           = "input";
 214 const char js_iterator_str[]        = "__iterator__";
 215 const char js_length_str[]          = "length";
 216 const char js_lineNumber_str[]      = "lineNumber";
 217 const char js_message_str[]         = "message";
 218 const char js_name_str[]            = "name";
 219 const char js_next_str[]            = "next";
 220 const char js_noSuchMethod_str[]    = "__noSuchMethod__";
 221 const char js_object_str[]          = "object";
 222 const char js_proto_str[]           = "__proto__";
 223 const char js_setter_str[]          = "setter";
 224 const char js_set_str[]             = "set";
 225 const char js_stack_str[]           = "stack";
 226 const char js_toSource_str[]        = "toSource";
 227 const char js_toString_str[]        = "toString";
 228 const char js_toLocaleString_str[]  = "toLocaleString";
 229 const char js_undefined_str[]       = "undefined";
 230 const char js_valueOf_str[]         = "valueOf";
 231 const char js_toJSON_str[]          = "toJSON";
 232 const char js_enumerable_str[]      = "enumerable";
 233 const char js_configurable_str[]    = "configurable";
 234 const char js_writable_str[]        = "writable";
 235 const char js_value_str[]           = "value";
 236
 237 #if JS_HAS_XML_SUPPORT
 238 const char js_etago_str[]           = "</";
 239 const char js_namespace_str[]       = "namespace";
 240 const char js_ptagc_str[]           = "/>";
 241 const char js_qualifier_str[]       = "::";
 242 const char js_space_str[]           = " ";
 243 const char js_stago_str[]           = "<";
 244 const char js_star_str[]            = "*";
 245 const char js_starQualifier_str[]   = "*::";
 246 const char js_tagc_str[]            = ">";
 247 const char js_xml_str[]             = "xml";
 248 #endif
 249
 250 #if JS_HAS_GENERATORS
 251 const char js_close_str[]           = "close";
 252 const char js_send_str[]            = "send";
 253 #endif
 254
 255 #ifdef NARCISSUS
 256 const char js___call___str[]         = "__call__";
 257 const char js___construct___str[]    = "__construct__";
 258 const char js___hasInstance___str[]  = "__hasInstance__";
 259 const char js_ExecutionContext_str[] = "ExecutionContext";
 260 const char js_current_str[]          = "current";
 261 #endif
 262
 263 /*
 264  * JSAtomState.doubleAtoms and JSAtomState.stringAtoms hashtable entry. To
 265  * support pinned and interned string atoms, we use the lowest bits of the
 266  * keyAndFlags field to store ATOM_PINNED and ATOM_INTERNED flags.
 267  */
 268 typedef struct JSAtomHashEntry {
 269     JSDHashEntryHdr hdr;
 270     jsuword         keyAndFlags;
 271 } JSAtomHashEntry;
 272
 273 #define ATOM_ENTRY_FLAG_MASK            (ATOM_PINNED | ATOM_INTERNED)
 274
 275 JS_STATIC_ASSERT(ATOM_ENTRY_FLAG_MASK < JSVAL_ALIGN);
 276
 277 /*
 278  * Helper macros to access and modify JSAtomHashEntry.
 279  */
 280 #define TO_ATOM_ENTRY(hdr)              ((JSAtomHashEntry *) hdr)
 281 #define ATOM_ENTRY_KEY(entry)                                                 \
 282     ((void *)((entry)->keyAndFlags & ~ATOM_ENTRY_FLAG_MASK))
 283 #define ATOM_ENTRY_FLAGS(entry)                                               \
 284     ((uintN)((entry)->keyAndFlags & ATOM_ENTRY_FLAG_MASK))
 285 #define INIT_ATOM_ENTRY(entry, key)                                           \
 286     ((void)((entry)->keyAndFlags = (jsuword)(key)))
 287 #define ADD_ATOM_ENTRY_FLAGS(entry, flags)                                    \
 288     ((void)((entry)->keyAndFlags |= (jsuword)(flags)))
 289 #define CLEAR_ATOM_ENTRY_FLAGS(entry, flags)                                  \
 290     ((void)((entry)->keyAndFlags &= ~(jsuword)(flags)))
 291
 292 static JSDHashNumber
 293 HashDouble(JSDHashTable *table, const void *key);
 294
 295 static JSBool
 296 MatchDouble(JSDHashTable *table, const JSDHashEntryHdr *hdr, const void *key);
 297
 298 static JSDHashNumber
 299 HashString(JSDHashTable *table, const void *key);
 300
 301 static JSBool
 302 MatchString(JSDHashTable *table, const JSDHashEntryHdr *hdr, const void *key);
 303
 304 static const JSDHashTableOps DoubleHashOps = {
 305     JS_DHashAllocTable,
 306     JS_DHashFreeTable,
 307     HashDouble,
 308     MatchDouble,
 309     JS_DHashMoveEntryStub,
 310     JS_DHashClearEntryStub,
 311     JS_DHashFinalizeStub,
 312     NULL
 313 };
 314
 315 static const JSDHashTableOps StringHashOps = {
 316     JS_DHashAllocTable,
 317     JS_DHashFreeTable,
 318     HashString,
 319     MatchString,
 320     JS_DHashMoveEntryStub,
 321     JS_DHashClearEntryStub,
 322     JS_DHashFinalizeStub,
 323     NULL
 324 };
 325
 326 #define IS_DOUBLE_TABLE(table)      ((table)->ops == &DoubleHashOps)
 327 #define IS_STRING_TABLE(table)      ((table)->ops == &StringHashOps)
 328
 329 #define IS_INITIALIZED_STATE(state) IS_DOUBLE_TABLE(&(state)->doubleAtoms)
 330
 331 static JSDHashNumber
 332 HashDouble(JSDHashTable *table, const void *key)
 333 {
 334     JS_ASSERT(IS_DOUBLE_TABLE(table));
 335     return JS_HASH_DOUBLE(*(jsdouble *)key);
 336 }
 337
 338 static JSDHashNumber
 339 HashString(JSDHashTable *table, const void *key)
 340 {
 341     JS_ASSERT(IS_STRING_TABLE(table));
 342     return js_HashString((JSString *)key);
 343 }
 344
 345 static JSBool
 346 MatchDouble(JSDHashTable *table, const JSDHashEntryHdr *hdr, const void *key)
 347 {
 348     JSAtomHashEntry *entry = TO_ATOM_ENTRY(hdr);
 349     jsdouble d1, d2;
 350
 351     JS_ASSERT(IS_DOUBLE_TABLE(table));
 352     if (entry->keyAndFlags == 0) {
 353         /* See comments in MatchString. */
 354         return JS_FALSE;
 355     }
 356
 357     d1 = *(jsdouble *)ATOM_ENTRY_KEY(entry);
 358     d2 = *(jsdouble *)key;
 359     if (JSDOUBLE_IS_NaN(d1))
 360         return JSDOUBLE_IS_NaN(d2);
 361 #if defined(XP_WIN)
 362     /* XXX MSVC miscompiles such that (NaN == 0) */
 363     if (JSDOUBLE_IS_NaN(d2))
 364         return JS_FALSE;
 365 #endif
 366     return d1 == d2;
 367 }
 368
 369 static JSBool
 370 MatchString(JSDHashTable *table, const JSDHashEntryHdr *hdr, const void *key)
 371 {
 372     JSAtomHashEntry *entry = TO_ATOM_ENTRY(hdr);
 373
 374     JS_ASSERT(IS_STRING_TABLE(table));
 375     if (entry->keyAndFlags == 0) {
 376         /*
 377          * This happens when js_AtomizeString adds a new hash entry and
 378          * releases the lock but before it takes the lock the second time to
 379          * initialize keyAndFlags for the entry.
 380          *
 381          * We always return false for such entries so JS_DHashTableOperate
 382          * never finds them. We clean them during GC's sweep phase.
 383          *
 384          * It means that with a contested lock or when GC is triggered outside
 385          * the lock we may end up adding two entries, but this is a price for
 386          * simpler code.
 387          */
 388         return JS_FALSE;
 389     }
 390     return js_EqualStrings((JSString *)ATOM_ENTRY_KEY(entry), (JSString *)key);
 391 }
 392
 393 /*
 394  * For a browser build from 2007-08-09 after the browser starts up there are
 395  * just 55 double atoms, but over 15000 string atoms. Not to penalize more
 396  * economical embeddings allocating too much memory initially we initialize
 397  * atomized strings with just 1K entries.
 398  */
 399 #define JS_STRING_HASH_COUNT   1024
 400 #define JS_DOUBLE_HASH_COUNT   64
 401
 402 JSBool
 403 js_InitAtomState(JSRuntime *rt)
 404 {
 405     JSAtomState *state = &rt->atomState;
 406
 407    /*
 408     * The caller must zero the state before calling this function.
 409     */
 410     JS_ASSERT(!state->stringAtoms.ops);
 411     JS_ASSERT(!state->doubleAtoms.ops);
 412
 413     if (!JS_DHashTableInit(&state->stringAtoms, &StringHashOps,
 414                            NULL, sizeof(JSAtomHashEntry),
 415                            JS_DHASH_DEFAULT_CAPACITY(JS_STRING_HASH_COUNT))) {
 416         state->stringAtoms.ops = NULL;
 417         return JS_FALSE;
 418     }
 419     JS_ASSERT(IS_STRING_TABLE(&state->stringAtoms));
 420
 421     if (!JS_DHashTableInit(&state->doubleAtoms, &DoubleHashOps,
 422                            NULL, sizeof(JSAtomHashEntry),
 423                            JS_DHASH_DEFAULT_CAPACITY(JS_DOUBLE_HASH_COUNT))) {
 424         state->doubleAtoms.ops = NULL;
 425         JS_DHashTableFinish(&state->stringAtoms);
 426         state->stringAtoms.ops = NULL;
 427         return JS_FALSE;
 428     }
 429     JS_ASSERT(IS_DOUBLE_TABLE(&state->doubleAtoms));
 430
 431 #ifdef JS_THREADSAFE
 432     js_InitLock(&state->lock);
 433 #endif
 434     JS_ASSERT(IS_INITIALIZED_STATE(state));
 435     return JS_TRUE;
 436 }
 437
 438 static JSDHashOperator
 439 js_string_uninterner(JSDHashTable *table, JSDHashEntryHdr *hdr,
 440                      uint32 number, void *arg)
 441 {
 442     JSAtomHashEntry *entry = TO_ATOM_ENTRY(hdr);
 443     JSRuntime *rt = (JSRuntime *)arg;
 444     JSString *str;
 445
 446     /*
 447      * Any string entry that remains at this point must be initialized, as the
 448      * last GC should clean any uninitialized ones.
 449      */
 450     JS_ASSERT(IS_STRING_TABLE(table));
 451     JS_ASSERT(entry->keyAndFlags != 0);
 452     str = (JSString *)ATOM_ENTRY_KEY(entry);
 453
 454     js_FinalizeStringRT(rt, str);
 455     return JS_DHASH_NEXT;
 456 }
 457
 458 void
 459 js_FinishAtomState(JSRuntime *rt)
 460 {
 461     JSAtomState *state = &rt->atomState;
 462
 463     if (!IS_INITIALIZED_STATE(state)) {
 464         /*
 465          * We are called with uninitialized state when JS_NewRuntime fails and
 466          * calls JS_DestroyRuntime on a partially initialized runtime.
 467          */
 468         return;
 469     }
 470
 471     JS_DHashTableEnumerate(&state->stringAtoms, js_string_uninterner, rt);
 472     JS_DHashTableFinish(&state->stringAtoms);
 473     JS_DHashTableFinish(&state->doubleAtoms);
 474
 475 #ifdef JS_THREADSAFE
 476     js_FinishLock(&state->lock);
 477 #endif
 478 #ifdef DEBUG
 479     memset(state, JS_FREE_PATTERN, sizeof *state);
 480 #endif
 481 }
 482
 483 JSBool
 484 js_InitCommonAtoms(JSContext *cx)
 485 {
 486     JSAtomState *state = &cx->runtime->atomState;
 487     uintN i;
 488     JSAtom **atoms;
 489
 490     atoms = COMMON_ATOMS_START(state);
 491     for (i = 0; i < JS_ARRAY_LENGTH(js_common_atom_names); i++, atoms++) {
 492         *atoms = js_Atomize(cx, js_common_atom_names[i],
 493                             strlen(js_common_atom_names[i]), ATOM_PINNED);
 494         if (!*atoms)
 495             return JS_FALSE;
 496     }
 497     JS_ASSERT((uint8 *)atoms - (uint8 *)state == LAZY_ATOM_OFFSET_START);
 498     memset(atoms, 0, ATOM_OFFSET_LIMIT - LAZY_ATOM_OFFSET_START);
 499
 500     cx->runtime->emptyString = ATOM_TO_STRING(state->emptyAtom);
 501     return JS_TRUE;
 502 }
 503
 504 static JSDHashOperator
 505 js_atom_unpinner(JSDHashTable *table, JSDHashEntryHdr *hdr,
 506                  uint32 number, void *arg)
 507 {
 508     JS_ASSERT(IS_STRING_TABLE(table));
 509     CLEAR_ATOM_ENTRY_FLAGS(TO_ATOM_ENTRY(hdr), ATOM_PINNED);
 510     return JS_DHASH_NEXT;
 511 }
 512
 513 void
 514 js_FinishCommonAtoms(JSContext *cx)
 515 {
 516     cx->runtime->emptyString = NULL;
 517     JSAtomState *state = &cx->runtime->atomState;
 518     JS_DHashTableEnumerate(&state->stringAtoms, js_atom_unpinner, NULL);
 519 #ifdef DEBUG
 520     memset(COMMON_ATOMS_START(state), JS_FREE_PATTERN,
 521            ATOM_OFFSET_LIMIT - ATOM_OFFSET_START);
 522 #endif
 523 }
 524
 525 static JSDHashOperator
 526 js_locked_atom_tracer(JSDHashTable *table, JSDHashEntryHdr *hdr,
 527                       uint32 number, void *arg)
 528 {
 529     JSAtomHashEntry *entry = TO_ATOM_ENTRY(hdr);
 530     JSTracer *trc = (JSTracer *)arg;
 531
 532     if (entry->keyAndFlags == 0) {
 533         /* Ignore uninitialized entries during tracing. */
 534         return JS_DHASH_NEXT;
 535     }
 536     JS_SET_TRACING_INDEX(trc, "locked_atom", (size_t)number);
 537     js_CallGCMarker(trc, ATOM_ENTRY_KEY(entry),
 538                     IS_STRING_TABLE(table) ? JSTRACE_STRING : JSTRACE_DOUBLE);
 539     return JS_DHASH_NEXT;
 540 }
 541
 542 static JSDHashOperator
 543 js_pinned_atom_tracer(JSDHashTable *table, JSDHashEntryHdr *hdr,
 544                         uint32 number, void *arg)
 545 {
 546     JSAtomHashEntry *entry = TO_ATOM_ENTRY(hdr);
 547     JSTracer *trc = (JSTracer *)arg;
 548     uintN flags = ATOM_ENTRY_FLAGS(entry);
 549
 550     JS_ASSERT(IS_STRING_TABLE(table));
 551     if (flags & (ATOM_PINNED | ATOM_INTERNED)) {
 552         JS_SET_TRACING_INDEX(trc,
 553                              flags & ATOM_PINNED
 554                              ? "pinned_atom"
 555                              : "interned_atom",
 556                              (size_t)number);
 557         js_CallGCMarker(trc, ATOM_ENTRY_KEY(entry), JSTRACE_STRING);
 558     }
 559     return JS_DHASH_NEXT;
 560 }
 561
 562 void
 563 js_TraceAtomState(JSTracer *trc)
 564 {
 565     JSRuntime *rt = trc->context->runtime;
 566     JSAtomState *state = &rt->atomState;
 567
 568     if (rt->gcKeepAtoms) {
 569         JS_DHashTableEnumerate(&state->doubleAtoms, js_locked_atom_tracer, trc);
 570         JS_DHashTableEnumerate(&state->stringAtoms, js_locked_atom_tracer, trc);
 571     } else {
 572         JS_DHashTableEnumerate(&state->stringAtoms, js_pinned_atom_tracer, trc);
 573     }
 574 }
 575
 576 static JSDHashOperator
 577 js_atom_sweeper(JSDHashTable *table, JSDHashEntryHdr *hdr,
 578                 uint32 number, void *arg)
 579 {
 580     JSAtomHashEntry *entry = TO_ATOM_ENTRY(hdr);
 581
 582     /* Remove uninitialized entries.  */
 583     if (entry->keyAndFlags == 0)
 584         return JS_DHASH_REMOVE;
 585
 586     if (ATOM_ENTRY_FLAGS(entry) & (ATOM_PINNED | ATOM_INTERNED)) {
 587         /* Pinned or interned key cannot be finalized. */
 588         JS_ASSERT(!js_IsAboutToBeFinalized(ATOM_ENTRY_KEY(entry)));
 589     } else if (js_IsAboutToBeFinalized(ATOM_ENTRY_KEY(entry))) {
 590         /* Remove entries with things about to be GC'ed. */
 591         return JS_DHASH_REMOVE;
 592     }
 593     return JS_DHASH_NEXT;
 594 }
 595
 596 void
 597 js_SweepAtomState(JSContext *cx)
 598 {
 599     JSAtomState *state = &cx->runtime->atomState;
 600
 601     JS_DHashTableEnumerate(&state->doubleAtoms, js_atom_sweeper, NULL);
 602     JS_DHashTableEnumerate(&state->stringAtoms, js_atom_sweeper, NULL);
 603
 604     /*
 605      * Optimize for simplicity and mutate table generation numbers even if the
 606      * sweeper has not removed any entries.
 607      */
 608     state->doubleAtoms.generation++;
 609     state->stringAtoms.generation++;
 610 }
 611
 612 JSAtom *
 613 js_AtomizeDouble(JSContext *cx, jsdouble d)
 614 {
 615     JSAtomState *state;
 616     JSDHashTable *table;
 617     JSAtomHashEntry *entry;
 618     uint32 gen;
 619     jsdouble *key;
 620     jsval v;
 621
 622     state = &cx->runtime->atomState;
 623     table = &state->doubleAtoms;
 624
 625     JS_LOCK(cx, &state->lock);
 626     entry = TO_ATOM_ENTRY(JS_DHashTableOperate(table, &d, JS_DHASH_ADD));
 627     if (!entry)
 628         goto failed_hash_add;
 629     if (entry->keyAndFlags == 0) {
 630         gen = ++table->generation;
 631         JS_UNLOCK(cx, &state->lock);
 632
 633         key = js_NewWeaklyRootedDouble(cx, d);
 634         if (!key)
 635             return NULL;
 636
 637         JS_LOCK(cx, &state->lock);
 638         if (table->generation == gen) {
 639             JS_ASSERT(entry->keyAndFlags == 0);
 640         } else {
 641             entry = TO_ATOM_ENTRY(JS_DHashTableOperate(table, key,
 642                                                        JS_DHASH_ADD));
 643             if (!entry)
 644                 goto failed_hash_add;
 645             if (entry->keyAndFlags != 0)
 646                 goto finish;
 647             ++table->generation;
 648         }
 649         INIT_ATOM_ENTRY(entry, key);
 650     }
 651
 652   finish:
 653     v = DOUBLE_TO_JSVAL((jsdouble *)ATOM_ENTRY_KEY(entry));
 654     cx->weakRoots.lastAtom = v;
 655     JS_UNLOCK(cx, &state->lock);
 656
 657     return (JSAtom *)v;
 658
 659   failed_hash_add:
 660     JS_UNLOCK(cx, &state->lock);
 661     JS_ReportOutOfMemory(cx);
 662     return NULL;
 663 }
 664
 665 JSAtom *
 666 js_AtomizeString(JSContext *cx, JSString *str, uintN flags)
 667 {
 668     jsval v;
 669     JSAtomState *state;
 670     JSDHashTable *table;
 671     JSAtomHashEntry *entry;
 672     JSString *key;
 673     uint32 gen;
 674
 675     JS_ASSERT(!(flags & ~(ATOM_PINNED|ATOM_INTERNED|ATOM_TMPSTR|ATOM_NOCOPY)));
 676     JS_ASSERT_IF(flags & ATOM_NOCOPY, flags & ATOM_TMPSTR);
 677
 678     if (str->isAtomized())
 679         return (JSAtom *) STRING_TO_JSVAL(str);
 680
 681     size_t length = str->length();
 682     if (length == 1) {
 683         jschar c = str->chars()[0];
 684         if (c < UNIT_STRING_LIMIT)
 685             return (JSAtom *) STRING_TO_JSVAL(JSString::unitString(c));
 686     }
 687
 688     /*
 689      * Here we know that JSString::intStringTable covers only 256 (or at least
 690      * not 1000 or more) chars. We rely on order here to resolve the unit vs.
 691      * int string atom identity issue by giving priority to unit strings for
 692      * '0' through '9' (see JSString::intString in jsstrinlines.h).
 693      */
 694     JS_STATIC_ASSERT(INT_STRING_LIMIT <= 999);
 695     if (2 <= length && length <= 3) {
 696         const jschar *chars = str->chars();
 697
 698         if ('1' <= chars[0] && chars[0] <= '9' &&
 699             '0' <= chars[1] && chars[1] <= '9' &&
 700             (length == 2 || ('0' <= chars[2] && chars[2] <= '9'))) {
 701             jsint i = (chars[0] - '0') * 10 + chars[1] - '0';
 702
 703             if (length == 3)
 704                 i = i * 10 + chars[2] - '0';
 705             if (jsuint(i) < INT_STRING_LIMIT)
 706                 return (JSAtom *) STRING_TO_JSVAL(JSString::intString(i));
 707         }
 708     }
 709
 710     state = &cx->runtime->atomState;
 711     table = &state->stringAtoms;
 712
 713     JS_LOCK(cx, &state->lock);
 714     entry = TO_ATOM_ENTRY(JS_DHashTableOperate(table, str, JS_DHASH_ADD));
 715     if (!entry)
 716         goto failed_hash_add;
 717     if (entry->keyAndFlags != 0) {
 718         key = (JSString *)ATOM_ENTRY_KEY(entry);
 719     } else {
 720         /*
 721          * We created a new hashtable entry. Unless str is already allocated
 722          * from the GC heap and flat, we have to release state->lock as
 723          * string construction is a complex operation. For example, it can
 724          * trigger GC which may rehash the table and make the entry invalid.
 725          */
 726         ++table->generation;
 727         if (!(flags & ATOM_TMPSTR) && str->isFlat()) {
 728             str->flatClearMutable();
 729             key = str;
 730         } else {
 731             gen = table->generation;
 732             JS_UNLOCK(cx, &state->lock);
 733
 734             if (flags & ATOM_TMPSTR) {
 735                 if (flags & ATOM_NOCOPY) {
 736                     key = js_NewString(cx, str->flatChars(), str->flatLength());
 737                     if (!key)
 738                         return NULL;
 739
 740                     /* Finish handing off chars to the GC'ed key string. */
 741                     str->mChars = NULL;
 742                 } else {
 743                     key = js_NewStringCopyN(cx, str->flatChars(), str->flatLength());
 744                     if (!key)
 745                         return NULL;
 746                 }
 747             } else {
 748                 JS_ASSERT(str->isDependent());
 749                 if (!js_UndependString(cx, str))
 750                     return NULL;
 751                 key = str;
 752             }
 753
 754             JS_LOCK(cx, &state->lock);
 755             if (table->generation == gen) {
 756                 JS_ASSERT(entry->keyAndFlags == 0);
 757             } else {
 758                 entry = TO_ATOM_ENTRY(JS_DHashTableOperate(table, key,
 759                                                            JS_DHASH_ADD));
 760                 if (!entry)
 761                     goto failed_hash_add;
 762                 if (entry->keyAndFlags != 0) {
 763                     key = (JSString *)ATOM_ENTRY_KEY(entry);
 764                     goto finish;
 765                 }
 766                 ++table->generation;
 767             }
 768         }
 769         INIT_ATOM_ENTRY(entry, key);
 770         key->flatSetAtomized();
 771     }
 772
 773   finish:
 774     ADD_ATOM_ENTRY_FLAGS(entry, flags & (ATOM_PINNED | ATOM_INTERNED));
 775     JS_ASSERT(key->isAtomized());
 776     v = STRING_TO_JSVAL(key);
 777     cx->weakRoots.lastAtom = v;
 778     JS_UNLOCK(cx, &state->lock);
 779     return (JSAtom *)v;
 780
 781   failed_hash_add:
 782     JS_UNLOCK(cx, &state->lock);
 783     JS_ReportOutOfMemory(cx);
 784     return NULL;
 785 }
 786
 787 JSAtom *
 788 js_Atomize(JSContext *cx, const char *bytes, size_t length, uintN flags)
 789 {
 790     jschar *chars;
 791     JSString str;
 792     JSAtom *atom;
 793
 794     /*
 795      * Avoiding the malloc in js_InflateString on shorter strings saves us
 796      * over 20,000 malloc calls on mozilla browser startup. This compares to
 797      * only 131 calls where the string is longer than a 31 char (net) buffer.
 798      * The vast majority of atomized strings are already in the hashtable. So
 799      * js_AtomizeString rarely has to copy the temp string we make.
 800      */
 801 #define ATOMIZE_BUF_MAX 32
 802     jschar inflated[ATOMIZE_BUF_MAX];
 803     size_t inflatedLength = ATOMIZE_BUF_MAX - 1;
 804
 805     if (length < ATOMIZE_BUF_MAX) {
 806         js_InflateStringToBuffer(cx, bytes, length, inflated, &inflatedLength);
 807         inflated[inflatedLength] = 0;
 808         chars = inflated;
 809     } else {
 810         inflatedLength = length;
 811         chars = js_InflateString(cx, bytes, &inflatedLength);
 812         if (!chars)
 813             return NULL;
 814         flags |= ATOM_NOCOPY;
 815     }
 816
 817     str.initFlat(chars, inflatedLength);
 818     atom = js_AtomizeString(cx, &str, ATOM_TMPSTR | flags);
 819     if (chars != inflated && str.flatChars())
 820         cx->free(chars);
 821     return atom;
 822 }
 823
 824 JSAtom *
 825 js_AtomizeChars(JSContext *cx, const jschar *chars, size_t length, uintN flags)
 826 {
 827     JSString str;
 828
 829     str.initFlat((jschar *)chars, length);
 830     return js_AtomizeString(cx, &str, ATOM_TMPSTR | flags);
 831 }
 832
 833 JSAtom *
 834 js_GetExistingStringAtom(JSContext *cx, const jschar *chars, size_t length)
 835 {
 836     JSString str, *str2;
 837     JSAtomState *state;
 838     JSDHashEntryHdr *hdr;
 839
 840     if (length == 1) {
 841         jschar c = *chars;
 842         if (c < UNIT_STRING_LIMIT)
 843             return (JSAtom *) STRING_TO_JSVAL(JSString::unitString(c));
 844     }
 845
 846     str.initFlat((jschar *)chars, length);
 847     state = &cx->runtime->atomState;
 848
 849     JS_LOCK(cx, &state->lock);
 850     hdr = JS_DHashTableOperate(&state->stringAtoms, &str, JS_DHASH_LOOKUP);
 851     str2 = JS_DHASH_ENTRY_IS_BUSY(hdr)
 852            ? (JSString *)ATOM_ENTRY_KEY(TO_ATOM_ENTRY(hdr))
 853            : NULL;
 854     JS_UNLOCK(cx, &state->lock);
 855
 856     return str2 ? (JSAtom *)STRING_TO_JSVAL(str2) : NULL;
 857 }
 858
 859 JSBool
 860 js_AtomizePrimitiveValue(JSContext *cx, jsval v, JSAtom **atomp)
 861 {
 862     JSAtom *atom;
 863
 864     if (JSVAL_IS_STRING(v)) {
 865         atom = js_AtomizeString(cx, JSVAL_TO_STRING(v), 0);
 866         if (!atom)
 867             return JS_FALSE;
 868     } else if (JSVAL_IS_DOUBLE(v)) {
 869         atom = js_AtomizeDouble(cx, *JSVAL_TO_DOUBLE(v));
 870         if (!atom)
 871             return JS_FALSE;
 872     } else {
 873         JS_ASSERT(JSVAL_IS_INT(v) || JSVAL_IS_BOOLEAN(v) ||
 874                   JSVAL_IS_NULL(v) || JSVAL_IS_VOID(v));
 875         atom = (JSAtom *)v;
 876     }
 877     *atomp = atom;
 878     return JS_TRUE;
 879 }
 880
 881 #ifdef DEBUG
 882
 883 static JSDHashOperator
 884 atom_dumper(JSDHashTable *table, JSDHashEntryHdr *hdr,
 885             uint32 number, void *arg)
 886 {
 887     JSAtomHashEntry *entry = TO_ATOM_ENTRY(hdr);
 888     FILE *fp = (FILE *)arg;
 889     void *key;
 890     uintN flags;
 891
 892     fprintf(fp, "%3u %08x ", number, (uintN)entry->hdr.keyHash);
 893     if (entry->keyAndFlags == 0) {
 894         fputs("<uninitialized>", fp);
 895     } else {
 896         key = ATOM_ENTRY_KEY(entry);
 897         if (IS_DOUBLE_TABLE(table)) {
 898             fprintf(fp, "%.16g", *(jsdouble *)key);
 899         } else {
 900             JS_ASSERT(IS_STRING_TABLE(table));
 901             js_FileEscapedString(fp, (JSString *)key, '"');
 902         }
 903         flags = ATOM_ENTRY_FLAGS(entry);
 904         if (flags != 0) {
 905             fputs((flags & (ATOM_PINNED | ATOM_INTERNED))
 906                   ? " pinned | interned"
 907                   : (flags & ATOM_PINNED) ? " pinned" : " interned",
 908                   fp);
 909         }
 910     }
 911     putc('\n', fp);
 912     return JS_DHASH_NEXT;
 913 }
 914
 915 JS_FRIEND_API(void)
 916 js_DumpAtoms(JSContext *cx, FILE *fp)
 917 {
 918     JSAtomState *state = &cx->runtime->atomState;
 919
 920     fprintf(fp, "stringAtoms table contents:\n");
 921     JS_DHashTableEnumerate(&state->stringAtoms, atom_dumper, fp);
 922 #ifdef JS_DHASHMETER
 923     JS_DHashTableDumpMeter(&state->stringAtoms, atom_dumper, fp);
 924 #endif
 925     putc('\n', fp);
 926
 927     fprintf(fp, "doubleAtoms table contents:\n");
 928     JS_DHashTableEnumerate(&state->doubleAtoms, atom_dumper, fp);
 929 #ifdef JS_DHASHMETER
 930     JS_DHashTableDumpMeter(&state->doubleAtoms, atom_dumper, fp);
 931 #endif
 932     putc('\n', fp);
 933 }
 934
 935 #endif
 936
 937 static JSHashNumber
 938 js_hash_atom_ptr(const void *key)
 939 {
 940     const JSAtom *atom = (const JSAtom *) key;
 941     return ATOM_HASH(atom);
 942 }
 943
 944 #if JS_BITS_PER_WORD == 32
 945 # define TEMP_SIZE_START_LOG2   5
 946 #else
 947 # define TEMP_SIZE_START_LOG2   6
 948 #endif
 949 #define TEMP_SIZE_LIMIT_LOG2    (TEMP_SIZE_START_LOG2 + NUM_TEMP_FREELISTS)
 950
 951 #define TEMP_SIZE_START         JS_BIT(TEMP_SIZE_START_LOG2)
 952 #define TEMP_SIZE_LIMIT         JS_BIT(TEMP_SIZE_LIMIT_LOG2)
 953
 954 JS_STATIC_ASSERT(TEMP_SIZE_START >= sizeof(JSHashTable));
 955
 956 static void *
 957 js_alloc_temp_space(void *priv, size_t size)
 958 {
 959     Parser *parser = (Parser *) priv;
 960
 961     void *space;
 962     if (size < TEMP_SIZE_LIMIT) {
 963         int bin = JS_CeilingLog2(size) - TEMP_SIZE_START_LOG2;
 964         JS_ASSERT(unsigned(bin) < NUM_TEMP_FREELISTS);
 965
 966         space = parser->tempFreeList[bin];
 967         if (space) {
 968             parser->tempFreeList[bin] = *(void **)space;
 969             return space;
 970         }
 971     }
 972
 973     parser->context->tempPool.allocate(space, size);
 974     if (!space)
 975         js_ReportOutOfScriptQuota(parser->context);
 976     return space;
 977 }
 978
 979 static void
 980 js_free_temp_space(void *priv, void *item, size_t size)
 981 {
 982     if (size >= TEMP_SIZE_LIMIT)
 983         return;
 984
 985     Parser *parser = (Parser *) priv;
 986     int bin = JS_CeilingLog2(size) - TEMP_SIZE_START_LOG2;
 987     JS_ASSERT(unsigned(bin) < NUM_TEMP_FREELISTS);
 988
 989     *(void **)item = parser->tempFreeList[bin];
 990     parser->tempFreeList[bin] = item;
 991 }
 992
 993 static JSHashEntry *
 994 js_alloc_temp_entry(void *priv, const void *key)
 995 {
 996     Parser *parser = (Parser *) priv;
 997     JSAtomListElement *ale;
 998
 999     ale = parser->aleFreeList;
1000     if (ale) {
1001         parser->aleFreeList = ALE_NEXT(ale);
1002         return &ale->entry;
1003     }
1004
1005     parser->context->tempPool.allocateType<JSAtomListElement>(ale);
1006     if (!ale) {
1007         js_ReportOutOfScriptQuota(parser->context);
1008         return NULL;
1009     }
1010     return &ale->entry;
1011 }
1012
1013 static void
1014 js_free_temp_entry(void *priv, JSHashEntry *he, uintN flag)
1015 {
1016     Parser *parser = (Parser *) priv;
1017     JSAtomListElement *ale = (JSAtomListElement *) he;
1018
1019     ALE_SET_NEXT(ale, parser->aleFreeList);
1020     parser->aleFreeList = ale;
1021 }
1022
1023 static JSHashAllocOps temp_alloc_ops = {
1024     js_alloc_temp_space,    js_free_temp_space,
1025     js_alloc_temp_entry,    js_free_temp_entry
1026 };
1027
1028 JSAtomListElement *
1029 JSAtomList::rawLookup(JSAtom *atom, JSHashEntry **&hep)
1030 {
1031     JSAtomListElement *ale;
1032
1033     if (table) {
1034         hep = JS_HashTableRawLookup(table, ATOM_HASH(atom), atom);
1035         ale = *hep ? (JSAtomListElement *) *hep : NULL;
1036     } else {
1037         JSHashEntry **alep = &list;
1038         hep = NULL;
1039         while ((ale = (JSAtomListElement *)*alep) != NULL) {
1040             if (ALE_ATOM(ale) == atom) {
1041                 /* Hit, move atom's element to the front of the list. */
1042                 *alep = ale->entry.next;
1043                 ale->entry.next = list;
1044                 list = &ale->entry;
1045                 break;
1046             }
1047             alep = &ale->entry.next;
1048         }
1049     }
1050     return ale;
1051 }
1052
1053 #define ATOM_LIST_HASH_THRESHOLD        12
1054
1055 JSAtomListElement *
1056 JSAtomList::add(Parser *parser, JSAtom *atom, AddHow how)
1057 {
1058     JS_ASSERT(!set);
1059
1060     JSAtomListElement *ale, *ale2, *next;
1061     JSHashEntry **hep;
1062
1063     ale = rawLookup(atom, hep);
1064     if (!ale || how != UNIQUE) {
1065         if (count < ATOM_LIST_HASH_THRESHOLD && !table) {
1066             /* Few enough for linear search and no hash table yet needed. */
1067             ale = (JSAtomListElement *)js_alloc_temp_entry(parser, atom);
1068             if (!ale)
1069                 return NULL;
1070             ALE_SET_ATOM(ale, atom);
1071
1072             if (how == HOIST) {
1073                 ale->entry.next = NULL;
1074                 hep = (JSHashEntry **) &list;
1075                 while (*hep)
1076                     hep = &(*hep)->next;
1077                 *hep = &ale->entry;
1078             } else {
1079                 ale->entry.next = list;
1080                 list = &ale->entry;
1081             }
1082         } else {
1083             /*
1084              * We should hash, or else we already are hashing, but count was
1085              * reduced by JSAtomList::rawRemove below ATOM_LIST_HASH_THRESHOLD.
1086              * Check whether we should create the table.
1087              */
1088             if (!table) {
1089                 /* No hash table yet, so hep had better be null! */
1090                 JS_ASSERT(!hep);
1091                 table = JS_NewHashTable(count + 1, js_hash_atom_ptr,
1092                                         JS_CompareValues, JS_CompareValues,
1093                                         &temp_alloc_ops, parser);
1094                 if (!table)
1095                     return NULL;
1096
1097                 /*
1098                  * Set ht->nentries explicitly, because we are moving entries
1099                  * from list to ht, not calling JS_HashTable(Raw|)Add.
1100                  */
1101                 table->nentries = count;
1102
1103                 /*
1104                  * Insert each ale on list into the new hash table. Append to
1105                  * the hash chain rather than inserting at the bucket head, to
1106                  * preserve order among entries with the same key.
1107                  */
1108                 for (ale2 = (JSAtomListElement *)list; ale2; ale2 = next) {
1109                     next = ALE_NEXT(ale2);
1110                     ale2->entry.keyHash = ATOM_HASH(ALE_ATOM(ale2));
1111                     hep = JS_HashTableRawLookup(table, ale2->entry.keyHash,
1112                                                 ale2->entry.key);
1113                     while (*hep)
1114                         hep = &(*hep)->next;
1115                     *hep = &ale2->entry;
1116                     ale2->entry.next = NULL;
1117                 }
1118                 list = NULL;
1119
1120                 /* Set hep for insertion of atom's ale, immediately below. */
1121                 hep = JS_HashTableRawLookup(table, ATOM_HASH(atom), atom);
1122             }
1123
1124             /* Finally, add an entry for atom into the hash bucket at hep. */
1125             ale = (JSAtomListElement *)
1126                   JS_HashTableRawAdd(table, hep, ATOM_HASH(atom), atom, NULL);
1127             if (!ale)
1128                 return NULL;
1129
1130             /*
1131              * If hoisting, move ale to the end of its chain after we called
1132              * JS_HashTableRawAdd, since RawAdd may have grown the table and
1133              * then recomputed hep to refer to the pointer to the first entry
1134              * with the given key.
1135              */
1136             if (how == HOIST && ale->entry.next) {
1137                 JS_ASSERT(*hep == &ale->entry);
1138                 *hep = ale->entry.next;
1139                 ale->entry.next = NULL;
1140                 do {
1141                     hep = &(*hep)->next;
1142                 } while (*hep);
1143                 *hep = &ale->entry;
1144             }
1145         }
1146
1147         ALE_SET_INDEX(ale, count++);
1148     }
1149     return ale;
1150 }
1151
1152 void
1153 JSAtomList::rawRemove(Parser *parser, JSAtomListElement *ale, JSHashEntry **hep)
1154 {
1155     JS_ASSERT(!set);
1156     JS_ASSERT(count != 0);
1157
1158     if (table) {
1159         JS_ASSERT(hep);
1160         JS_HashTableRawRemove(table, hep, &ale->entry);
1161     } else {
1162         JS_ASSERT(!hep);
1163         hep = &list;
1164         while (*hep != &ale->entry) {
1165             JS_ASSERT(*hep);
1166             hep = &(*hep)->next;
1167         }
1168         *hep = ale->entry.next;
1169         js_free_temp_entry(parser, &ale->entry, HT_FREE_ENTRY);
1170     }
1171
1172     --count;
1173 }
1174
1175 JSAutoAtomList::~JSAutoAtomList()
1176 {
1177     if (table) {
1178         JS_HashTableDestroy(table);
1179     } else {
1180         JSHashEntry *hep = list;
1181         while (hep) {
1182             JSHashEntry *next = hep->next;
1183             js_free_temp_entry(parser, hep, HT_FREE_ENTRY);
1184             hep = next;
1185         }
1186     }
1187 }
1188
1189 JSAtomListElement *
1190 JSAtomListIterator::operator ()()
1191 {
1192     JSAtomListElement *ale;
1193     JSHashTable *ht;
1194
1195     if (index == uint32(-1))
1196         return NULL;
1197
1198     ale = next;
1199     if (!ale) {
1200         ht = list->table;
1201         if (!ht)
1202             goto done;
1203         do {
1204             if (index == JS_BIT(JS_HASH_BITS - ht->shift))
1205                 goto done;
1206             next = (JSAtomListElement *) ht->buckets[index++];
1207         } while (!next);
1208         ale = next;
1209     }
1210
1211     next = ALE_NEXT(ale);
1212     return ale;
1213
1214   done:
1215     index = uint32(-1);
1216     return NULL;
1217 }
1218
1219 static intN
1220 js_map_atom(JSHashEntry *he, intN i, void *arg)
1221 {
1222     JSAtomListElement *ale = (JSAtomListElement *)he;
1223     JSAtom **vector = (JSAtom **) arg;
1224
1225     vector[ALE_INDEX(ale)] = ALE_ATOM(ale);
1226     return HT_ENUMERATE_NEXT;
1227 }
1228
1229 #ifdef DEBUG
1230 static jsrefcount js_atom_map_count;
1231 static jsrefcount js_atom_map_hash_table_count;
1232 #endif
1233
1234 void
1235 js_InitAtomMap(JSContext *cx, JSAtomMap *map, JSAtomList *al)
1236 {
1237     JSAtom **vector;
1238     JSAtomListElement *ale;
1239     uint32 count;
1240
1241     /* Map length must already be initialized. */
1242     JS_ASSERT(al->count == map->length);
1243 #ifdef DEBUG
1244     JS_ATOMIC_INCREMENT(&js_atom_map_count);
1245 #endif
1246     ale = (JSAtomListElement *)al->list;
1247     if (!ale && !al->table) {
1248         JS_ASSERT(!map->vector);
1249         return;
1250     }
1251
1252     count = al->count;
1253     vector = map->vector;
1254     if (al->table) {
1255 #ifdef DEBUG
1256         JS_ATOMIC_INCREMENT(&js_atom_map_hash_table_count);
1257 #endif
1258         JS_HashTableEnumerateEntries(al->table, js_map_atom, vector);
1259     } else {
1260         do {
1261             vector[ALE_INDEX(ale)] = ALE_ATOM(ale);
1262         } while ((ale = ALE_NEXT(ale)) != NULL);
1263     }
1264     al->clear();
1265 }