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"
  48 #include "jshash.h"
  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 "jsxml.h"
  62
  63 #include "jsstrinlines.h"
  64 #include "jsatominlines.h"
  65 #include "jsobjinlines.h"
  66
  67 using namespace js;
  68 using namespace js::gc;
  69
  70 /*
  71  * ATOM_HASH assumes that JSHashNumber is 32-bit even on 64-bit systems.
  72  */
  73 JS_STATIC_ASSERT(sizeof(JSHashNumber) == 4);
  74 JS_STATIC_ASSERT(sizeof(JSAtom *) == JS_BYTES_PER_WORD);
  75
  76 /*
  77  * Start and limit offsets for atom pointers in JSAtomState must be aligned
  78  * on the word boundary.
  79  */
  80 JS_STATIC_ASSERT(ATOM_OFFSET_START % sizeof(JSAtom *) == 0);
  81 JS_STATIC_ASSERT(ATOM_OFFSET_LIMIT % sizeof(JSAtom *) == 0);
  82
  83 /*
  84  * JS_BOOLEAN_STR and JS_TYPE_STR assume that boolean names starts from the
  85  * index 1 and type name starts from the index 1+2 atoms in JSAtomState.
  86  */
  87 JS_STATIC_ASSERT(1 * sizeof(JSAtom *) ==
  88                  offsetof(JSAtomState, booleanAtoms) - ATOM_OFFSET_START);
  89 JS_STATIC_ASSERT((1 + 2) * sizeof(JSAtom *) ==
  90                  offsetof(JSAtomState, typeAtoms) - ATOM_OFFSET_START);
  91
  92 const char *
  93 js_AtomToPrintableString(JSContext *cx, JSAtom *atom, JSAutoByteString *bytes)
  94 {
  95     return js_ValueToPrintable(cx, StringValue(ATOM_TO_STRING(atom)), bytes);
  96 }
  97
  98 #define JS_PROTO(name,code,init) const char js_##name##_str[] = #name;
  99 #include "jsproto.tbl"
 100 #undef JS_PROTO
 101
 102 /*
 103  * String constants for common atoms defined in JSAtomState starting from
 104  * JSAtomState.emptyAtom until JSAtomState.lazy.
 105  *
 106  * The elements of the array after the first empty string define strings
 107  * corresponding to the two boolean literals, false and true, followed by the
 108  * JSType enumerators from jspubtd.h starting with "undefined" for JSTYPE_VOID
 109  * (which is special-value 2) and continuing as initialized below. The static
 110  * asserts check these relations.
 111  */
 112 JS_STATIC_ASSERT(JSTYPE_LIMIT == 8);
 113 JS_STATIC_ASSERT(JSTYPE_VOID == 0);
 114
 115 const char *const js_common_atom_names[] = {
 116     "",                         /* emptyAtom                    */
 117     js_false_str,               /* booleanAtoms[0]              */
 118     js_true_str,                /* booleanAtoms[1]              */
 119     js_undefined_str,           /* typeAtoms[JSTYPE_VOID]       */
 120     js_object_str,              /* typeAtoms[JSTYPE_OBJECT]     */
 121     js_function_str,            /* typeAtoms[JSTYPE_FUNCTION]   */
 122     "string",                   /* typeAtoms[JSTYPE_STRING]     */
 123     "number",                   /* typeAtoms[JSTYPE_NUMBER]     */
 124     "boolean",                  /* typeAtoms[JSTYPE_BOOLEAN]    */
 125     js_null_str,                /* typeAtoms[JSTYPE_NULL]       */
 126     "xml",                      /* typeAtoms[JSTYPE_XML]        */
 127     js_null_str,                /* nullAtom                     */
 128
 129 #define JS_PROTO(name,code,init) js_##name##_str,
 130 #include "jsproto.tbl"
 131 #undef JS_PROTO
 132
 133     js_anonymous_str,           /* anonymousAtom                */
 134     js_apply_str,               /* applyAtom                    */
 135     js_arguments_str,           /* argumentsAtom                */
 136     js_arity_str,               /* arityAtom                    */
 137     js_call_str,                /* callAtom                     */
 138     js_callee_str,              /* calleeAtom                   */
 139     js_caller_str,              /* callerAtom                   */
 140     js_class_prototype_str,     /* classPrototypeAtom           */
 141     js_constructor_str,         /* constructorAtom              */
 142     js_each_str,                /* eachAtom                     */
 143     js_eval_str,                /* evalAtom                     */
 144     js_fileName_str,            /* fileNameAtom                 */
 145     js_get_str,                 /* getAtom                      */
 146     js_global_str,              /* globalAtom                   */
 147     js_ignoreCase_str,          /* ignoreCaseAtom               */
 148     js_index_str,               /* indexAtom                    */
 149     js_input_str,               /* inputAtom                    */
 150     "toISOString",              /* toISOStringAtom              */
 151     js_iterator_str,            /* iteratorAtom                 */
 152     js_join_str,                /* joinAtom                     */
 153     js_lastIndex_str,           /* lastIndexAtom                */
 154     js_length_str,              /* lengthAtom                   */
 155     js_lineNumber_str,          /* lineNumberAtom               */
 156     js_message_str,             /* messageAtom                  */
 157     js_multiline_str,           /* multilineAtom                */
 158     js_name_str,                /* nameAtom                     */
 159     js_next_str,                /* nextAtom                     */
 160     js_noSuchMethod_str,        /* noSuchMethodAtom             */
 161     "[object Null]",            /* objectNullAtom               */
 162     "[object Undefined]",       /* objectUndefinedAtom          */
 163     js_proto_str,               /* protoAtom                    */
 164     js_set_str,                 /* setAtom                      */
 165     js_source_str,              /* sourceAtom                   */
 166     js_stack_str,               /* stackAtom                    */
 167     js_sticky_str,              /* stickyAtom                   */
 168     js_toGMTString_str,         /* toGMTStringAtom              */
 169     js_toLocaleString_str,      /* toLocaleStringAtom           */
 170     js_toSource_str,            /* toSourceAtom                 */
 171     js_toString_str,            /* toStringAtom                 */
 172     js_toUTCString_str,         /* toUTCStringAtom              */
 173     js_valueOf_str,             /* valueOfAtom                  */
 174     js_toJSON_str,              /* toJSONAtom                   */
 175     "(void 0)",                 /* void0Atom                    */
 176     js_enumerable_str,          /* enumerableAtom               */
 177     js_configurable_str,        /* configurableAtom             */
 178     js_writable_str,            /* writableAtom                 */
 179     js_value_str,               /* valueAtom                    */
 180     js_test_str,                /* testAtom                     */
 181     "use strict",               /* useStrictAtom                */
 182     "loc",                      /* locAtom                      */
 183     "line",                     /* lineAtom                     */
 184     "Infinity",                 /* InfinityAtom                 */
 185     "NaN",                      /* NaNAtom                      */
 186     "builder",                  /* builderAtom                  */
 187
 188 #if JS_HAS_XML_SUPPORT
 189     js_etago_str,               /* etagoAtom                    */
 190     js_namespace_str,           /* namespaceAtom                */
 191     js_ptagc_str,               /* ptagcAtom                    */
 192     js_qualifier_str,           /* qualifierAtom                */
 193     js_space_str,               /* spaceAtom                    */
 194     js_stago_str,               /* stagoAtom                    */
 195     js_star_str,                /* starAtom                     */
 196     js_starQualifier_str,       /* starQualifierAtom            */
 197     js_tagc_str,                /* tagcAtom                     */
 198     js_xml_str,                 /* xmlAtom                      */
 199     "@mozilla.org/js/function", /* functionNamespaceURIAtom     */
 200 #endif
 201
 202     "Proxy",                    /* ProxyAtom                    */
 203
 204     "getOwnPropertyDescriptor", /* getOwnPropertyDescriptorAtom */
 205     "getPropertyDescriptor",    /* getPropertyDescriptorAtom    */
 206     "defineProperty",           /* definePropertyAtom           */
 207     "delete",                   /* deleteAtom                   */
 208     "getOwnPropertyNames",      /* getOwnPropertyNames          */
 209     "enumerate",                /* enumerateAtom                */
 210     "fix",                      /* fixAtom                      */
 211
 212     "has",                      /* hasAtom                      */
 213     "hasOwn",                   /* hasOwnAtom                   */
 214     "keys",                     /* keysAtom                     */
 215     "iterate"                   /* iterateAtom                  */
 216 };
 217
 218 JS_STATIC_ASSERT(JS_ARRAY_LENGTH(js_common_atom_names) * sizeof(JSAtom *) ==
 219                  LAZY_ATOM_OFFSET_START - ATOM_OFFSET_START);
 220
 221 /*
 222  * Interpreter macros called by the trace recorder assume common atom indexes
 223  * fit in one byte of immediate operand.
 224  */
 225 JS_STATIC_ASSERT(JS_ARRAY_LENGTH(js_common_atom_names) < 256);
 226
 227 const size_t js_common_atom_count = JS_ARRAY_LENGTH(js_common_atom_names);
 228
 229 const char js_anonymous_str[]       = "anonymous";
 230 const char js_apply_str[]           = "apply";
 231 const char js_arguments_str[]       = "arguments";
 232 const char js_arity_str[]           = "arity";
 233 const char js_call_str[]            = "call";
 234 const char js_callee_str[]          = "callee";
 235 const char js_caller_str[]          = "caller";
 236 const char js_class_prototype_str[] = "prototype";
 237 const char js_constructor_str[]     = "constructor";
 238 const char js_each_str[]            = "each";
 239 const char js_eval_str[]            = "eval";
 240 const char js_fileName_str[]        = "fileName";
 241 const char js_get_str[]             = "get";
 242 const char js_getter_str[]          = "getter";
 243 const char js_global_str[]          = "global";
 244 const char js_ignoreCase_str[]      = "ignoreCase";
 245 const char js_index_str[]           = "index";
 246 const char js_input_str[]           = "input";
 247 const char js_iterator_str[]        = "__iterator__";
 248 const char js_join_str[]            = "join";
 249 const char js_lastIndex_str[]       = "lastIndex";
 250 const char js_length_str[]          = "length";
 251 const char js_lineNumber_str[]      = "lineNumber";
 252 const char js_message_str[]         = "message";
 253 const char js_multiline_str[]       = "multiline";
 254 const char js_name_str[]            = "name";
 255 const char js_next_str[]            = "next";
 256 const char js_noSuchMethod_str[]    = "__noSuchMethod__";
 257 const char js_object_str[]          = "object";
 258 const char js_proto_str[]           = "__proto__";
 259 const char js_setter_str[]          = "setter";
 260 const char js_set_str[]             = "set";
 261 const char js_source_str[]          = "source";
 262 const char js_stack_str[]           = "stack";
 263 const char js_sticky_str[]          = "sticky";
 264 const char js_toGMTString_str[]     = "toGMTString";
 265 const char js_toLocaleString_str[]  = "toLocaleString";
 266 const char js_toSource_str[]        = "toSource";
 267 const char js_toString_str[]        = "toString";
 268 const char js_toUTCString_str[]     = "toUTCString";
 269 const char js_undefined_str[]       = "undefined";
 270 const char js_valueOf_str[]         = "valueOf";
 271 const char js_toJSON_str[]          = "toJSON";
 272 const char js_enumerable_str[]      = "enumerable";
 273 const char js_configurable_str[]    = "configurable";
 274 const char js_writable_str[]        = "writable";
 275 const char js_value_str[]           = "value";
 276 const char js_test_str[]            = "test";
 277
 278 #if JS_HAS_XML_SUPPORT
 279 const char js_etago_str[]           = "</";
 280 const char js_namespace_str[]       = "namespace";
 281 const char js_ptagc_str[]           = "/>";
 282 const char js_qualifier_str[]       = "::";
 283 const char js_space_str[]           = " ";
 284 const char js_stago_str[]           = "<";
 285 const char js_star_str[]            = "*";
 286 const char js_starQualifier_str[]   = "*::";
 287 const char js_tagc_str[]            = ">";
 288 const char js_xml_str[]             = "xml";
 289 #endif
 290
 291 #if JS_HAS_GENERATORS
 292 const char js_close_str[]           = "close";
 293 const char js_send_str[]            = "send";
 294 #endif
 295
 296 /*
 297  * Helper macros to access and modify JSAtomHashEntry.
 298  */
 299
 300 inline AtomEntryType
 301 StringToInitialAtomEntry(JSString *str)
 302 {
 303     return (AtomEntryType) str;
 304 }
 305
 306 inline uintN
 307 AtomEntryFlags(AtomEntryType entry)
 308 {
 309     return (uintN) (entry & ATOM_ENTRY_FLAG_MASK);
 310 }
 311
 312 /*
 313  * Conceptually, we have compressed a HashMap<JSAtom *, uint> into a
 314  * HashMap<size_t>. Here, we promise that we are only changing the "value" of
 315  * the HashMap entry, so the const_cast is safe.
 316  */
 317
 318 inline void
 319 AddAtomEntryFlags(const AtomEntryType &entry, uintN flags)
 320 {
 321     const_cast<AtomEntryType &>(entry) |= AtomEntryType(flags);
 322 }
 323
 324 inline void
 325 ClearAtomEntryFlags(const AtomEntryType &entry, uintN flags)
 326 {
 327     const_cast<AtomEntryType &>(entry) &= ~AtomEntryType(flags);
 328 }
 329
 330 /*
 331  * For a browser build from 2007-08-09 after the browser starts up there are
 332  * just 55 double atoms, but over 15000 string atoms. Not to penalize more
 333  * economical embeddings allocating too much memory initially we initialize
 334  * atomized strings with just 1K entries.
 335  */
 336 #define JS_STRING_HASH_COUNT   1024
 337
 338 JSBool
 339 js_InitAtomState(JSRuntime *rt)
 340 {
 341     JSAtomState *state = &rt->atomState;
 342
 343     JS_ASSERT(!state->atoms.initialized());
 344     if (!state->atoms.init(JS_STRING_HASH_COUNT))
 345         return false;
 346
 347 #ifdef JS_THREADSAFE
 348     js_InitLock(&state->lock);
 349 #endif
 350     JS_ASSERT(state->atoms.initialized());
 351     return JS_TRUE;
 352 }
 353
 354 void
 355 js_FinishAtomState(JSRuntime *rt)
 356 {
 357     JSAtomState *state = &rt->atomState;
 358
 359     if (!state->atoms.initialized()) {
 360         /*
 361          * We are called with uninitialized state when JS_NewRuntime fails and
 362          * calls JS_DestroyRuntime on a partially initialized runtime.
 363          */
 364         return;
 365     }
 366
 367     for (AtomSet::Range r = state->atoms.all(); !r.empty(); r.popFront()) {
 368         JSString *str = AtomEntryToKey(r.front());
 369         js_FinalizeStringRT(rt, str);
 370     }
 371
 372 #ifdef JS_THREADSAFE
 373     js_FinishLock(&state->lock);
 374 #endif
 375 }
 376
 377 JSBool
 378 js_InitCommonAtoms(JSContext *cx)
 379 {
 380     JSAtomState *state = &cx->runtime->atomState;
 381     uintN i;
 382     JSAtom **atoms;
 383
 384     atoms = COMMON_ATOMS_START(state);
 385     for (i = 0; i < JS_ARRAY_LENGTH(js_common_atom_names); i++, atoms++) {
 386         *atoms = js_Atomize(cx, js_common_atom_names[i],
 387                             strlen(js_common_atom_names[i]), ATOM_PINNED);
 388         if (!*atoms)
 389             return JS_FALSE;
 390     }
 391     JS_ASSERT((uint8 *)atoms - (uint8 *)state == LAZY_ATOM_OFFSET_START);
 392     memset(atoms, 0, ATOM_OFFSET_LIMIT - LAZY_ATOM_OFFSET_START);
 393
 394     cx->runtime->emptyString = ATOM_TO_STRING(state->emptyAtom);
 395     return JS_TRUE;
 396 }
 397
 398 void
 399 js_FinishCommonAtoms(JSContext *cx)
 400 {
 401     cx->runtime->emptyString = NULL;
 402     JSAtomState *state = &cx->runtime->atomState;
 403
 404     for (AtomSet::Range r = state->atoms.all(); !r.empty(); r.popFront())
 405         ClearAtomEntryFlags(r.front(), ATOM_PINNED);
 406
 407 #ifdef DEBUG
 408     memset(COMMON_ATOMS_START(state), JS_FREE_PATTERN,
 409            ATOM_OFFSET_LIMIT - ATOM_OFFSET_START);
 410 #endif
 411 }
 412
 413 void
 414 js_TraceAtomState(JSTracer *trc)
 415 {
 416     JSRuntime *rt = trc->context->runtime;
 417     JSAtomState *state = &rt->atomState;
 418
 419 #ifdef DEBUG
 420     size_t number = 0;
 421 #endif
 422
 423     if (rt->gcKeepAtoms) {
 424         for (AtomSet::Range r = state->atoms.all(); !r.empty(); r.popFront()) {
 425             JS_SET_TRACING_INDEX(trc, "locked_atom", number++);
 426             MarkString(trc, AtomEntryToKey(r.front()));
 427         }
 428     } else {
 429         for (AtomSet::Range r = state->atoms.all(); !r.empty(); r.popFront()) {
 430             AtomEntryType entry = r.front();
 431             uintN flags = AtomEntryFlags(entry);
 432             if (flags & (ATOM_PINNED | ATOM_INTERNED)) {
 433                 JS_SET_TRACING_INDEX(trc,
 434                                      flags & ATOM_PINNED
 435                                      ? "pinned_atom"
 436                                      : "interned_atom",
 437                                      number++);
 438                 MarkString(trc, AtomEntryToKey(entry));
 439             }
 440         }
 441     }
 442 }
 443
 444 void
 445 js_SweepAtomState(JSContext *cx)
 446 {
 447     JSAtomState *state = &cx->runtime->atomState;
 448
 449     for (AtomSet::Enum e(state->atoms); !e.empty(); e.popFront()) {
 450         AtomEntryType entry = e.front();
 451         if (AtomEntryFlags(entry) & (ATOM_PINNED | ATOM_INTERNED)) {
 452             /* Pinned or interned key cannot be finalized. */
 453             JS_ASSERT(!IsAboutToBeFinalized(cx, AtomEntryToKey(entry)));
 454         } else if (IsAboutToBeFinalized(cx, AtomEntryToKey(entry))) {
 455             e.removeFront();
 456         }
 457     }
 458 }
 459
 460 JSAtom *
 461 js_AtomizeString(JSContext *cx, JSString *strArg, uintN flags)
 462 {
 463     JS_ASSERT(!(flags & ~(ATOM_PINNED|ATOM_INTERNED|ATOM_TMPSTR|ATOM_NOCOPY)));
 464     JS_ASSERT_IF(flags & ATOM_NOCOPY, flags & ATOM_TMPSTR);
 465
 466     if (strArg->isAtomized())
 467         return STRING_TO_ATOM(strArg);
 468
 469     JSLinearString *str = strArg->ensureLinear(cx);
 470     if (!str)
 471         return NULL;
 472
 473     const jschar *chars = str->chars();
 474     size_t length = str->length();
 475
 476     JSString *staticStr = JSString::lookupStaticString(chars, length);
 477     if (staticStr)
 478         return STRING_TO_ATOM(staticStr);
 479
 480     JSAtomState *state = &cx->runtime->atomState;
 481     AtomSet &atoms = state->atoms;
 482
 483     AutoLockAtomsCompartment lock(cx);
 484     AtomSet::AddPtr p = atoms.lookupForAdd(str);
 485
 486     /* Hashing the string should have flattened it if it was a rope. */
 487     JS_ASSERT(str->isFlat() || str->isDependent());
 488
 489     JSLinearString *key;
 490     if (p) {
 491         key = AtomEntryToKey(*p);
 492     } else {
 493         /*
 494          * Ensure that any atomized string lives only in the default
 495          * compartment.
 496          */
 497         bool needNewString = !!(flags & ATOM_TMPSTR) ||
 498                              str->asCell()->compartment() != cx->runtime->atomsCompartment;
 499
 500         /*
 501          * Unless str is already comes from the default compartment and flat,
 502          * we have to relookup the key as the last ditch GC invoked from the
 503          * string allocation or OOM handling may unlock the default
 504          * compartment lock.
 505          */
 506         if (!needNewString && str->isFlat()) {
 507             str->flatClearExtensible();
 508             key = str;
 509             atoms.add(p, StringToInitialAtomEntry(key));
 510         } else {
 511             if (needNewString) {
 512                 SwitchToCompartment sc(cx, cx->runtime->atomsCompartment);
 513                 if (flags & ATOM_NOCOPY) {
 514                     key = js_NewString(cx, const_cast<jschar *>(str->flatChars()), length);
 515                     if (!key)
 516                         return NULL;
 517
 518                     /* Finish handing off chars to the GC'ed key string. */
 519                     JS_ASSERT(flags & ATOM_TMPSTR);
 520                     str->u.chars = NULL;
 521                 } else {
 522                     key = js_NewStringCopyN(cx, chars, length);
 523                     if (!key)
 524                         return NULL;
 525                 }
 526             } else {
 527                 JS_ASSERT(str->isDependent());
 528                 if (!str->undepend(cx))
 529                     return NULL;
 530                 key = str;
 531             }
 532
 533             if (!atoms.relookupOrAdd(p, key, StringToInitialAtomEntry(key))) {
 534                 JS_ReportOutOfMemory(cx); /* SystemAllocPolicy does not report */
 535                 return NULL;
 536             }
 537         }
 538         key->flatSetAtomized();
 539     }
 540
 541     AddAtomEntryFlags(*p, flags & (ATOM_PINNED | ATOM_INTERNED));
 542
 543     JSAtom *atom = STRING_TO_ATOM(key);
 544     return atom;
 545 }
 546
 547 JSAtom *
 548 js_Atomize(JSContext *cx, const char *bytes, size_t length, uintN flags)
 549 {
 550     jschar *chars;
 551     JSString str;
 552     JSAtom *atom;
 553
 554     CHECK_REQUEST(cx);
 555
 556     /*
 557      * Avoiding the malloc in js_InflateString on shorter strings saves us
 558      * over 20,000 malloc calls on mozilla browser startup. This compares to
 559      * only 131 calls where the string is longer than a 31 char (net) buffer.
 560      * The vast majority of atomized strings are already in the hashtable. So
 561      * js_AtomizeString rarely has to copy the temp string we make.
 562      */
 563 #define ATOMIZE_BUF_MAX 32
 564     jschar inflated[ATOMIZE_BUF_MAX];
 565     size_t inflatedLength = ATOMIZE_BUF_MAX - 1;
 566
 567     if (length < ATOMIZE_BUF_MAX) {
 568         js_InflateStringToBuffer(cx, bytes, length, inflated, &inflatedLength);
 569         inflated[inflatedLength] = 0;
 570         chars = inflated;
 571     } else {
 572         inflatedLength = length;
 573         chars = js_InflateString(cx, bytes, &inflatedLength);
 574         if (!chars)
 575             return NULL;
 576         flags |= ATOM_NOCOPY;
 577     }
 578
 579     str.initFlat(chars, inflatedLength);
 580     atom = js_AtomizeString(cx, &str, ATOM_TMPSTR | flags);
 581     if (chars != inflated && str.flatChars())
 582         cx->free(chars);
 583     return atom;
 584 }
 585
 586 JSAtom *
 587 js_AtomizeChars(JSContext *cx, const jschar *chars, size_t length, uintN flags)
 588 {
 589     JSString str;
 590
 591     CHECK_REQUEST(cx);
 592
 593     if (!CheckStringLength(cx, length))
 594         return NULL;
 595
 596     str.initFlatNotTerminated((jschar *)chars, length);
 597     return js_AtomizeString(cx, &str, ATOM_TMPSTR | flags);
 598 }
 599
 600 JSAtom *
 601 js_GetExistingStringAtom(JSContext *cx, const jschar *chars, size_t length)
 602 {
 603     JSString str, *str2;
 604     JSAtomState *state;
 605
 606     if (length == 1) {
 607         jschar c = *chars;
 608         if (c < UNIT_STRING_LIMIT)
 609             return STRING_TO_ATOM(JSString::unitString(c));
 610     }
 611
 612     str.initFlatNotTerminated((jschar *)chars, length);
 613     state = &cx->runtime->atomState;
 614
 615     JS_LOCK(cx, &state->lock);
 616     AtomSet::Ptr p = state->atoms.lookup(str.assertIsFlat());
 617     str2 = p ? AtomEntryToKey(*p) : NULL;
 618     JS_UNLOCK(cx, &state->lock);
 619
 620     return str2 ? STRING_TO_ATOM(str2) : NULL;
 621 }
 622
 623 #ifdef DEBUG
 624 JS_FRIEND_API(void)
 625 js_DumpAtoms(JSContext *cx, FILE *fp)
 626 {
 627     JSAtomState *state = &cx->runtime->atomState;
 628
 629     fprintf(fp, "atoms table contents:\n");
 630     unsigned number = 0;
 631     for (AtomSet::Range r = state->atoms.all(); !r.empty(); r.popFront()) {
 632         AtomEntryType entry = r.front();
 633         fprintf(fp, "%3u ", number++);
 634         if (entry == 0) {
 635             fputs("<uninitialized>", fp);
 636         } else {
 637             JSAtom *key = AtomEntryToKey(entry);
 638             FileEscapedString(fp, key, '"');
 639             uintN flags = AtomEntryFlags(entry);
 640             if (flags != 0) {
 641                 fputs((flags & (ATOM_PINNED | ATOM_INTERNED))
 642                       ? " pinned | interned"
 643                       : (flags & ATOM_PINNED) ? " pinned" : " interned",
 644                       fp);
 645             }
 646         }
 647         putc('\n', fp);
 648     }
 649     putc('\n', fp);
 650 }
 651 #endif
 652
 653 static JSHashNumber
 654 js_hash_atom_ptr(const void *key)
 655 {
 656     const JSAtom *atom = (const JSAtom *) key;
 657     return ATOM_HASH(atom);
 658 }
 659
 660 #if JS_BITS_PER_WORD == 32
 661 # define TEMP_SIZE_START_LOG2   5
 662 #else
 663 # define TEMP_SIZE_START_LOG2   6
 664 #endif
 665 #define TEMP_SIZE_LIMIT_LOG2    (TEMP_SIZE_START_LOG2 + NUM_TEMP_FREELISTS)
 666
 667 #define TEMP_SIZE_START         JS_BIT(TEMP_SIZE_START_LOG2)
 668 #define TEMP_SIZE_LIMIT         JS_BIT(TEMP_SIZE_LIMIT_LOG2)
 669
 670 JS_STATIC_ASSERT(TEMP_SIZE_START >= sizeof(JSHashTable));
 671
 672 static void *
 673 js_alloc_temp_space(void *priv, size_t size)
 674 {
 675     Parser *parser = (Parser *) priv;
 676
 677     void *space;
 678     if (size < TEMP_SIZE_LIMIT) {
 679         int bin = JS_CeilingLog2(size) - TEMP_SIZE_START_LOG2;
 680         JS_ASSERT(unsigned(bin) < NUM_TEMP_FREELISTS);
 681
 682         space = parser->tempFreeList[bin];
 683         if (space) {
 684             parser->tempFreeList[bin] = *(void **)space;
 685             return space;
 686         }
 687     }
 688
 689     JS_ARENA_ALLOCATE(space, &parser->context->tempPool, size);
 690     if (!space)
 691         js_ReportOutOfScriptQuota(parser->context);
 692     return space;
 693 }
 694
 695 static void
 696 js_free_temp_space(void *priv, void *item, size_t size)
 697 {
 698     if (size >= TEMP_SIZE_LIMIT)
 699         return;
 700
 701     Parser *parser = (Parser *) priv;
 702     int bin = JS_CeilingLog2(size) - TEMP_SIZE_START_LOG2;
 703     JS_ASSERT(unsigned(bin) < NUM_TEMP_FREELISTS);
 704
 705     *(void **)item = parser->tempFreeList[bin];
 706     parser->tempFreeList[bin] = item;
 707 }
 708
 709 static JSHashEntry *
 710 js_alloc_temp_entry(void *priv, const void *key)
 711 {
 712     Parser *parser = (Parser *) priv;
 713     JSAtomListElement *ale;
 714
 715     ale = parser->aleFreeList;
 716     if (ale) {
 717         parser->aleFreeList = ALE_NEXT(ale);
 718         return &ale->entry;
 719     }
 720
 721     JS_ARENA_ALLOCATE_TYPE(ale, JSAtomListElement, &parser->context->tempPool);
 722     if (!ale) {
 723         js_ReportOutOfScriptQuota(parser->context);
 724         return NULL;
 725     }
 726     return &ale->entry;
 727 }
 728
 729 static void
 730 js_free_temp_entry(void *priv, JSHashEntry *he, uintN flag)
 731 {
 732     Parser *parser = (Parser *) priv;
 733     JSAtomListElement *ale = (JSAtomListElement *) he;
 734
 735     ALE_SET_NEXT(ale, parser->aleFreeList);
 736     parser->aleFreeList = ale;
 737 }
 738
 739 static JSHashAllocOps temp_alloc_ops = {
 740     js_alloc_temp_space,    js_free_temp_space,
 741     js_alloc_temp_entry,    js_free_temp_entry
 742 };
 743
 744 JSAtomListElement *
 745 JSAtomList::rawLookup(JSAtom *atom, JSHashEntry **&hep)
 746 {
 747     if (table) {
 748         hep = JS_HashTableRawLookup(table, ATOM_HASH(atom), atom);
 749         return (JSAtomListElement *) *hep;
 750     }
 751
 752     JSHashEntry **alep = &list;
 753     hep = NULL;
 754     JSAtomListElement *ale;
 755     while ((ale = (JSAtomListElement *)*alep) != NULL) {
 756         if (ALE_ATOM(ale) == atom) {
 757             /* Hit, move atom's element to the front of the list. */
 758             *alep = ale->entry.next;
 759             ale->entry.next = list;
 760             list = &ale->entry;
 761             break;
 762         }
 763         alep = &ale->entry.next;
 764     }
 765     return ale;
 766 }
 767
 768 #define ATOM_LIST_HASH_THRESHOLD        12
 769
 770 JSAtomListElement *
 771 JSAtomList::add(Parser *parser, JSAtom *atom, AddHow how)
 772 {
 773     JS_ASSERT(!set);
 774
 775     JSAtomListElement *ale, *ale2, *next;
 776     JSHashEntry **hep;
 777
 778     ale = rawLookup(atom, hep);
 779     if (!ale || how != UNIQUE) {
 780         if (count < ATOM_LIST_HASH_THRESHOLD && !table) {
 781             /* Few enough for linear search and no hash table yet needed. */
 782             ale = (JSAtomListElement *)js_alloc_temp_entry(parser, atom);
 783             if (!ale)
 784                 return NULL;
 785             ALE_SET_ATOM(ale, atom);
 786
 787             if (how == HOIST) {
 788                 ale->entry.next = NULL;
 789                 hep = (JSHashEntry **) &list;
 790                 while (*hep)
 791                     hep = &(*hep)->next;
 792                 *hep = &ale->entry;
 793             } else {
 794                 ale->entry.next = list;
 795                 list = &ale->entry;
 796             }
 797         } else {
 798             /*
 799              * We should hash, or else we already are hashing, but count was
 800              * reduced by JSAtomList::rawRemove below ATOM_LIST_HASH_THRESHOLD.
 801              * Check whether we should create the table.
 802              */
 803             if (!table) {
 804                 /* No hash table yet, so hep had better be null! */
 805                 JS_ASSERT(!hep);
 806                 table = JS_NewHashTable(count + 1, js_hash_atom_ptr,
 807                                         JS_CompareValues, JS_CompareValues,
 808                                         &temp_alloc_ops, parser);
 809                 if (!table)
 810                     return NULL;
 811
 812                 /*
 813                  * Set ht->nentries explicitly, because we are moving entries
 814                  * from list to ht, not calling JS_HashTable(Raw|)Add.
 815                  */
 816                 table->nentries = count;
 817
 818                 /*
 819                  * Insert each ale on list into the new hash table. Append to
 820                  * the hash chain rather than inserting at the bucket head, to
 821                  * preserve order among entries with the same key.
 822                  */
 823                 for (ale2 = (JSAtomListElement *)list; ale2; ale2 = next) {
 824                     next = ALE_NEXT(ale2);
 825                     ale2->entry.keyHash = ATOM_HASH(ALE_ATOM(ale2));
 826                     hep = JS_HashTableRawLookup(table, ale2->entry.keyHash,
 827                                                 ale2->entry.key);
 828                     while (*hep)
 829                         hep = &(*hep)->next;
 830                     *hep = &ale2->entry;
 831                     ale2->entry.next = NULL;
 832                 }
 833                 list = NULL;
 834
 835                 /* Set hep for insertion of atom's ale, immediately below. */
 836                 hep = JS_HashTableRawLookup(table, ATOM_HASH(atom), atom);
 837             }
 838
 839             /* Finally, add an entry for atom into the hash bucket at hep. */
 840             ale = (JSAtomListElement *)
 841                   JS_HashTableRawAdd(table, hep, ATOM_HASH(atom), atom, NULL);
 842             if (!ale)
 843                 return NULL;
 844
 845             /*
 846              * If hoisting, move ale to the end of its chain after we called
 847              * JS_HashTableRawAdd, since RawAdd may have grown the table and
 848              * then recomputed hep to refer to the pointer to the first entry
 849              * with the given key.
 850              */
 851             if (how == HOIST && ale->entry.next) {
 852                 JS_ASSERT(*hep == &ale->entry);
 853                 *hep = ale->entry.next;
 854                 ale->entry.next = NULL;
 855                 do {
 856                     hep = &(*hep)->next;
 857                 } while (*hep);
 858                 *hep = &ale->entry;
 859             }
 860         }
 861
 862         ALE_SET_INDEX(ale, count++);
 863     }
 864     return ale;
 865 }
 866
 867 void
 868 JSAtomList::rawRemove(Parser *parser, JSAtomListElement *ale, JSHashEntry **hep)
 869 {
 870     JS_ASSERT(!set);
 871     JS_ASSERT(count != 0);
 872
 873     if (table) {
 874         JS_ASSERT(hep);
 875         JS_HashTableRawRemove(table, hep, &ale->entry);
 876     } else {
 877         JS_ASSERT(!hep);
 878         hep = &list;
 879         while (*hep != &ale->entry) {
 880             JS_ASSERT(*hep);
 881             hep = &(*hep)->next;
 882         }
 883         *hep = ale->entry.next;
 884         js_free_temp_entry(parser, &ale->entry, HT_FREE_ENTRY);
 885     }
 886
 887     --count;
 888 }
 889
 890 JSAutoAtomList::~JSAutoAtomList()
 891 {
 892     if (table) {
 893         JS_HashTableDestroy(table);
 894     } else {
 895         JSHashEntry *hep = list;
 896         while (hep) {
 897             JSHashEntry *next = hep->next;
 898             js_free_temp_entry(parser, hep, HT_FREE_ENTRY);
 899             hep = next;
 900         }
 901     }
 902 }
 903
 904 JSAtomListElement *
 905 JSAtomListIterator::operator ()()
 906 {
 907     JSAtomListElement *ale;
 908     JSHashTable *ht;
 909
 910     if (index == uint32(-1))
 911         return NULL;
 912
 913     ale = next;
 914     if (!ale) {
 915         ht = list->table;
 916         if (!ht)
 917             goto done;
 918         do {
 919             if (index == JS_BIT(JS_HASH_BITS - ht->shift))
 920                 goto done;
 921             next = (JSAtomListElement *) ht->buckets[index++];
 922         } while (!next);
 923         ale = next;
 924     }
 925
 926     next = ALE_NEXT(ale);
 927     return ale;
 928
 929   done:
 930     index = uint32(-1);
 931     return NULL;
 932 }
 933
 934 static intN
 935 js_map_atom(JSHashEntry *he, intN i, void *arg)
 936 {
 937     JSAtomListElement *ale = (JSAtomListElement *)he;
 938     JSAtom **vector = (JSAtom **) arg;
 939
 940     vector[ALE_INDEX(ale)] = ALE_ATOM(ale);
 941     return HT_ENUMERATE_NEXT;
 942 }
 943
 944 #ifdef DEBUG
 945 static jsrefcount js_atom_map_count;
 946 static jsrefcount js_atom_map_hash_table_count;
 947 #endif
 948
 949 void
 950 js_InitAtomMap(JSContext *cx, JSAtomMap *map, JSAtomList *al)
 951 {
 952     JSAtom **vector;
 953     JSAtomListElement *ale;
 954     uint32 count;
 955
 956     /* Map length must already be initialized. */
 957     JS_ASSERT(al->count == map->length);
 958 #ifdef DEBUG
 959     JS_ATOMIC_INCREMENT(&js_atom_map_count);
 960 #endif
 961     ale = (JSAtomListElement *)al->list;
 962     if (!ale && !al->table) {
 963         JS_ASSERT(!map->vector);
 964         return;
 965     }
 966
 967     count = al->count;
 968     vector = map->vector;
 969     if (al->table) {
 970 #ifdef DEBUG
 971         JS_ATOMIC_INCREMENT(&js_atom_map_hash_table_count);
 972 #endif
 973         JS_HashTableEnumerateEntries(al->table, js_map_atom, vector);
 974     } else {
 975         do {
 976             vector[ALE_INDEX(ale)] = ALE_ATOM(ale);
 977         } while ((ale = ALE_NEXT(ale)) != NULL);
 978     }
 979     al->clear();
 980 }
 981
 982 #if JS_HAS_XML_SUPPORT
 983 bool
 984 js_InternNonIntElementIdSlow(JSContext *cx, JSObject *obj, const Value &idval,
 985                              jsid *idp)
 986 {
 987     JS_ASSERT(idval.isObject());
 988     if (obj->isXML()) {
 989         *idp = OBJECT_TO_JSID(&idval.toObject());
 990         return true;
 991     }
 992
 993     if (!js_IsFunctionQName(cx, &idval.toObject(), idp))
 994         return JS_FALSE;
 995     if (!JSID_IS_VOID(*idp))
 996         return true;
 997
 998     return js_ValueToStringId(cx, idval, idp);
 999 }
1000
1001 bool
1002 js_InternNonIntElementIdSlow(JSContext *cx, JSObject *obj, const Value &idval,
1003                              jsid *idp, Value *vp)
1004 {
1005     JS_ASSERT(idval.isObject());
1006     if (obj->isXML()) {
1007         JSObject &idobj = idval.toObject();
1008         *idp = OBJECT_TO_JSID(&idobj);
1009         vp->setObject(idobj);
1010         return true;
1011     }
1012
1013     if (!js_IsFunctionQName(cx, &idval.toObject(), idp))
1014         return JS_FALSE;
1015     if (!JSID_IS_VOID(*idp)) {
1016         *vp = IdToValue(*idp);
1017         return true;
1018     }
1019
1020     if (js_ValueToStringId(cx, idval, idp)) {
1021         vp->setString(JSID_TO_STRING(*idp));
1022         return true;
1023     }
1024     return false;
1025 }
1026 #endif