mirror of
https://gitlab.winehq.org/wine/wine-gecko.git
synced 2024-09-13 09:24:08 -07:00
613 lines
25 KiB
C
613 lines
25 KiB
C
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
|
|
* vim: set ts=8 sts=4 et sw=4 tw=99:
|
|
* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
#ifndef jsdhash_h___
|
|
#define jsdhash_h___
|
|
|
|
/*
|
|
* Double hashing, a la Knuth 6.
|
|
*
|
|
* Try to keep this file in sync with xpcom/glue/pldhash.h.
|
|
*/
|
|
#include "jstypes.h"
|
|
#include "jsutil.h"
|
|
|
|
#if defined(__GNUC__) && defined(__i386__) && !defined(XP_OS2)
|
|
#define JS_DHASH_FASTCALL __attribute__ ((regparm (3),stdcall))
|
|
#elif defined(XP_WIN)
|
|
#define JS_DHASH_FASTCALL __fastcall
|
|
#else
|
|
#define JS_DHASH_FASTCALL
|
|
#endif
|
|
|
|
#ifdef DEBUG_XXXbrendan
|
|
#define JS_DHASHMETER 1
|
|
#endif
|
|
|
|
/* Table size limit, do not equal or exceed (see min&maxAlphaFrac, below). */
|
|
#undef JS_DHASH_SIZE_LIMIT
|
|
#define JS_DHASH_SIZE_LIMIT JS_BIT(24)
|
|
|
|
/* Minimum table size, or gross entry count (net is at most .75 loaded). */
|
|
#ifndef JS_DHASH_MIN_SIZE
|
|
#define JS_DHASH_MIN_SIZE 16
|
|
#elif (JS_DHASH_MIN_SIZE & (JS_DHASH_MIN_SIZE - 1)) != 0
|
|
#error "JS_DHASH_MIN_SIZE must be a power of two!"
|
|
#endif
|
|
|
|
/*
|
|
* Multiplicative hash uses an unsigned 32 bit integer and the golden ratio,
|
|
* expressed as a fixed-point 32-bit fraction.
|
|
*/
|
|
#define JS_DHASH_BITS 32
|
|
#define JS_DHASH_GOLDEN_RATIO 0x9E3779B9U
|
|
|
|
/* Primitive and forward-struct typedefs. */
|
|
typedef uint32_t JSDHashNumber;
|
|
typedef struct JSDHashEntryHdr JSDHashEntryHdr;
|
|
typedef struct JSDHashEntryStub JSDHashEntryStub;
|
|
typedef struct JSDHashTable JSDHashTable;
|
|
typedef struct JSDHashTableOps JSDHashTableOps;
|
|
|
|
/*
|
|
* Table entry header structure.
|
|
*
|
|
* In order to allow in-line allocation of key and value, we do not declare
|
|
* either here. Instead, the API uses const void *key as a formal parameter.
|
|
* The key need not be stored in the entry; it may be part of the value, but
|
|
* need not be stored at all.
|
|
*
|
|
* Callback types are defined below and grouped into the JSDHashTableOps
|
|
* structure, for single static initialization per hash table sub-type.
|
|
*
|
|
* Each hash table sub-type should nest the JSDHashEntryHdr structure at the
|
|
* front of its particular entry type. The keyHash member contains the result
|
|
* of multiplying the hash code returned from the hashKey callback (see below)
|
|
* by JS_DHASH_GOLDEN_RATIO, then constraining the result to avoid the magic 0
|
|
* and 1 values. The stored keyHash value is table size invariant, and it is
|
|
* maintained automatically by JS_DHashTableOperate -- users should never set
|
|
* it, and its only uses should be via the entry macros below.
|
|
*
|
|
* The JS_DHASH_ENTRY_IS_LIVE macro tests whether entry is neither free nor
|
|
* removed. An entry may be either busy or free; if busy, it may be live or
|
|
* removed. Consumers of this API should not access members of entries that
|
|
* are not live.
|
|
*
|
|
* However, use JS_DHASH_ENTRY_IS_BUSY for faster liveness testing of entries
|
|
* returned by JS_DHashTableOperate, as JS_DHashTableOperate never returns a
|
|
* non-live, busy (i.e., removed) entry pointer to its caller. See below for
|
|
* more details on JS_DHashTableOperate's calling rules.
|
|
*/
|
|
struct JSDHashEntryHdr {
|
|
JSDHashNumber keyHash; /* every entry must begin like this */
|
|
};
|
|
|
|
MOZ_ALWAYS_INLINE bool
|
|
JS_DHASH_ENTRY_IS_FREE(JSDHashEntryHdr* entry)
|
|
{
|
|
return entry->keyHash == 0;
|
|
}
|
|
MOZ_ALWAYS_INLINE bool
|
|
JS_DHASH_ENTRY_IS_BUSY(JSDHashEntryHdr* entry)
|
|
{
|
|
return !JS_DHASH_ENTRY_IS_FREE(entry);
|
|
}
|
|
MOZ_ALWAYS_INLINE bool
|
|
JS_DHASH_ENTRY_IS_LIVE(JSDHashEntryHdr* entry)
|
|
{
|
|
return entry->keyHash >= 2;
|
|
}
|
|
|
|
/*
|
|
* A JSDHashTable is currently 8 words (without the JS_DHASHMETER overhead)
|
|
* on most architectures, and may be allocated on the stack or within another
|
|
* structure or class (see below for the Init and Finish functions to use).
|
|
*
|
|
* To decide whether to use double hashing vs. chaining, we need to develop a
|
|
* trade-off relation, as follows:
|
|
*
|
|
* Let alpha be the load factor, esize the entry size in words, count the
|
|
* entry count, and pow2 the power-of-two table size in entries.
|
|
*
|
|
* (JSDHashTable overhead) > (JSHashTable overhead)
|
|
* (unused table entry space) > (malloc and .next overhead per entry) +
|
|
* (buckets overhead)
|
|
* (1 - alpha) * esize * pow2 > 2 * count + pow2
|
|
*
|
|
* Notice that alpha is by definition (count / pow2):
|
|
*
|
|
* (1 - alpha) * esize * pow2 > 2 * alpha * pow2 + pow2
|
|
* (1 - alpha) * esize > 2 * alpha + 1
|
|
*
|
|
* esize > (1 + 2 * alpha) / (1 - alpha)
|
|
*
|
|
* This assumes both tables must keep keyHash, key, and value for each entry,
|
|
* where key and value point to separately allocated strings or structures.
|
|
* If key and value can be combined into one pointer, then the trade-off is:
|
|
*
|
|
* esize > (1 + 3 * alpha) / (1 - alpha)
|
|
*
|
|
* If the entry value can be a subtype of JSDHashEntryHdr, rather than a type
|
|
* that must be allocated separately and referenced by an entry.value pointer
|
|
* member, and provided key's allocation can be fused with its entry's, then
|
|
* k (the words wasted per entry with chaining) is 4.
|
|
*
|
|
* To see these curves, feed gnuplot input like so:
|
|
*
|
|
* gnuplot> f(x,k) = (1 + k * x) / (1 - x)
|
|
* gnuplot> plot [0:.75] f(x,2), f(x,3), f(x,4)
|
|
*
|
|
* For k of 2 and a well-loaded table (alpha > .5), esize must be more than 4
|
|
* words for chaining to be more space-efficient than double hashing.
|
|
*
|
|
* Solving for alpha helps us decide when to shrink an underloaded table:
|
|
*
|
|
* esize > (1 + k * alpha) / (1 - alpha)
|
|
* esize - alpha * esize > 1 + k * alpha
|
|
* esize - 1 > (k + esize) * alpha
|
|
* (esize - 1) / (k + esize) > alpha
|
|
*
|
|
* alpha < (esize - 1) / (esize + k)
|
|
*
|
|
* Therefore double hashing should keep alpha >= (esize - 1) / (esize + k),
|
|
* assuming esize is not too large (in which case, chaining should probably be
|
|
* used for any alpha). For esize=2 and k=3, we want alpha >= .2; for esize=3
|
|
* and k=2, we want alpha >= .4. For k=4, esize could be 6, and alpha >= .5
|
|
* would still obtain. See the JS_DHASH_MIN_ALPHA macro further below.
|
|
*
|
|
* The current implementation uses a configurable lower bound on alpha, which
|
|
* defaults to .25, when deciding to shrink the table (while still respecting
|
|
* JS_DHASH_MIN_SIZE).
|
|
*
|
|
* Note a qualitative difference between chaining and double hashing: under
|
|
* chaining, entry addresses are stable across table shrinks and grows. With
|
|
* double hashing, you can't safely hold an entry pointer and use it after an
|
|
* ADD or REMOVE operation, unless you sample table->generation before adding
|
|
* or removing, and compare the sample after, dereferencing the entry pointer
|
|
* only if table->generation has not changed.
|
|
*
|
|
* The moral of this story: there is no one-size-fits-all hash table scheme,
|
|
* but for small table entry size, and assuming entry address stability is not
|
|
* required, double hashing wins.
|
|
*/
|
|
struct JSDHashTable {
|
|
const JSDHashTableOps *ops; /* virtual operations, see below */
|
|
void *data; /* ops- and instance-specific data */
|
|
int16_t hashShift; /* multiplicative hash shift */
|
|
uint8_t maxAlphaFrac; /* 8-bit fixed point max alpha */
|
|
uint8_t minAlphaFrac; /* 8-bit fixed point min alpha */
|
|
uint32_t entrySize; /* number of bytes in an entry */
|
|
uint32_t entryCount; /* number of entries in table */
|
|
uint32_t removedCount; /* removed entry sentinels in table */
|
|
uint32_t generation; /* entry storage generation number */
|
|
char *entryStore; /* entry storage */
|
|
#ifdef JS_DHASHMETER
|
|
struct JSDHashStats {
|
|
uint32_t searches; /* total number of table searches */
|
|
uint32_t steps; /* hash chain links traversed */
|
|
uint32_t hits; /* searches that found key */
|
|
uint32_t misses; /* searches that didn't find key */
|
|
uint32_t lookups; /* number of JS_DHASH_LOOKUPs */
|
|
uint32_t addMisses; /* adds that miss, and do work */
|
|
uint32_t addOverRemoved; /* adds that recycled a removed entry */
|
|
uint32_t addHits; /* adds that hit an existing entry */
|
|
uint32_t addFailures; /* out-of-memory during add growth */
|
|
uint32_t removeHits; /* removes that hit, and do work */
|
|
uint32_t removeMisses; /* useless removes that miss */
|
|
uint32_t removeFrees; /* removes that freed entry directly */
|
|
uint32_t removeEnums; /* removes done by Enumerate */
|
|
uint32_t grows; /* table expansions */
|
|
uint32_t shrinks; /* table contractions */
|
|
uint32_t compresses; /* table compressions */
|
|
uint32_t enumShrinks; /* contractions after Enumerate */
|
|
} stats;
|
|
#endif
|
|
};
|
|
|
|
/*
|
|
* Size in entries (gross, not net of free and removed sentinels) for table.
|
|
* We store hashShift rather than sizeLog2 to optimize the collision-free case
|
|
* in SearchTable.
|
|
*/
|
|
#define JS_DHASH_TABLE_SIZE(table) JS_BIT(JS_DHASH_BITS - (table)->hashShift)
|
|
|
|
/*
|
|
* Table space at entryStore is allocated and freed using these callbacks.
|
|
* The allocator should return null on error only (not if called with nbytes
|
|
* equal to 0; but note that jsdhash.c code will never call with 0 nbytes).
|
|
*/
|
|
typedef void *
|
|
(* JSDHashAllocTable)(JSDHashTable *table, uint32_t nbytes);
|
|
|
|
typedef void
|
|
(* JSDHashFreeTable) (JSDHashTable *table, void *ptr);
|
|
|
|
/*
|
|
* Compute the hash code for a given key to be looked up, added, or removed
|
|
* from table. A hash code may have any JSDHashNumber value.
|
|
*/
|
|
typedef JSDHashNumber
|
|
(* JSDHashHashKey) (JSDHashTable *table, const void *key);
|
|
|
|
/*
|
|
* Compare the key identifying entry in table with the provided key parameter.
|
|
* Return JS_TRUE if keys match, JS_FALSE otherwise.
|
|
*/
|
|
typedef JSBool
|
|
(* JSDHashMatchEntry)(JSDHashTable *table, const JSDHashEntryHdr *entry,
|
|
const void *key);
|
|
|
|
/*
|
|
* Copy the data starting at from to the new entry storage at to. Do not add
|
|
* reference counts for any strong references in the entry, however, as this
|
|
* is a "move" operation: the old entry storage at from will be freed without
|
|
* any reference-decrementing callback shortly.
|
|
*/
|
|
typedef void
|
|
(* JSDHashMoveEntry)(JSDHashTable *table, const JSDHashEntryHdr *from,
|
|
JSDHashEntryHdr *to);
|
|
|
|
/*
|
|
* Clear the entry and drop any strong references it holds. This callback is
|
|
* invoked during a JS_DHASH_REMOVE operation (see below for operation codes),
|
|
* but only if the given key is found in the table.
|
|
*/
|
|
typedef void
|
|
(* JSDHashClearEntry)(JSDHashTable *table, JSDHashEntryHdr *entry);
|
|
|
|
/*
|
|
* Called when a table (whether allocated dynamically by itself, or nested in
|
|
* a larger structure, or allocated on the stack) is finished. This callback
|
|
* allows table->ops-specific code to finalize table->data.
|
|
*/
|
|
typedef void
|
|
(* JSDHashFinalize) (JSDHashTable *table);
|
|
|
|
/*
|
|
* Initialize a new entry, apart from keyHash. This function is called when
|
|
* JS_DHashTableOperate's JS_DHASH_ADD case finds no existing entry for the
|
|
* given key, and must add a new one. At that point, entry->keyHash is not
|
|
* set yet, to avoid claiming the last free entry in a severely overloaded
|
|
* table.
|
|
*/
|
|
typedef JSBool
|
|
(* JSDHashInitEntry)(JSDHashTable *table, JSDHashEntryHdr *entry,
|
|
const void *key);
|
|
|
|
/*
|
|
* Finally, the "vtable" structure for JSDHashTable. The first eight hooks
|
|
* must be provided by implementations; they're called unconditionally by the
|
|
* generic jsdhash.c code. Hooks after these may be null.
|
|
*
|
|
* Summary of allocation-related hook usage with C++ placement new emphasis:
|
|
* allocTable Allocate raw bytes with malloc, no ctors run.
|
|
* freeTable Free raw bytes with free, no dtors run.
|
|
* initEntry Call placement new using default key-based ctor.
|
|
* Return JS_TRUE on success, JS_FALSE on error.
|
|
* moveEntry Call placement new using copy ctor, run dtor on old
|
|
* entry storage.
|
|
* clearEntry Run dtor on entry.
|
|
* finalize Stub unless table->data was initialized and needs to
|
|
* be finalized.
|
|
*
|
|
* Note the reason why initEntry is optional: the default hooks (stubs) clear
|
|
* entry storage: On successful JS_DHashTableOperate(tbl, key, JS_DHASH_ADD),
|
|
* the returned entry pointer addresses an entry struct whose keyHash member
|
|
* has been set non-zero, but all other entry members are still clear (null).
|
|
* JS_DHASH_ADD callers can test such members to see whether the entry was
|
|
* newly created by the JS_DHASH_ADD call that just succeeded. If placement
|
|
* new or similar initialization is required, define an initEntry hook. Of
|
|
* course, the clearEntry hook must zero or null appropriately.
|
|
*
|
|
* XXX assumes 0 is null for pointer types.
|
|
*/
|
|
struct JSDHashTableOps {
|
|
/* Mandatory hooks. All implementations must provide these. */
|
|
JSDHashAllocTable allocTable;
|
|
JSDHashFreeTable freeTable;
|
|
JSDHashHashKey hashKey;
|
|
JSDHashMatchEntry matchEntry;
|
|
JSDHashMoveEntry moveEntry;
|
|
JSDHashClearEntry clearEntry;
|
|
JSDHashFinalize finalize;
|
|
|
|
/* Optional hooks start here. If null, these are not called. */
|
|
JSDHashInitEntry initEntry;
|
|
};
|
|
|
|
/*
|
|
* Default implementations for the above ops.
|
|
*/
|
|
extern JS_PUBLIC_API(void *)
|
|
JS_DHashAllocTable(JSDHashTable *table, uint32_t nbytes);
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_DHashFreeTable(JSDHashTable *table, void *ptr);
|
|
|
|
extern JS_PUBLIC_API(JSDHashNumber)
|
|
JS_DHashStringKey(JSDHashTable *table, const void *key);
|
|
|
|
/* A minimal entry contains a keyHash header and a void key pointer. */
|
|
struct JSDHashEntryStub {
|
|
JSDHashEntryHdr hdr;
|
|
const void *key;
|
|
};
|
|
|
|
extern JS_PUBLIC_API(JSDHashNumber)
|
|
JS_DHashVoidPtrKeyStub(JSDHashTable *table, const void *key);
|
|
|
|
extern JS_PUBLIC_API(JSBool)
|
|
JS_DHashMatchEntryStub(JSDHashTable *table,
|
|
const JSDHashEntryHdr *entry,
|
|
const void *key);
|
|
|
|
extern JS_PUBLIC_API(JSBool)
|
|
JS_DHashMatchStringKey(JSDHashTable *table,
|
|
const JSDHashEntryHdr *entry,
|
|
const void *key);
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_DHashMoveEntryStub(JSDHashTable *table,
|
|
const JSDHashEntryHdr *from,
|
|
JSDHashEntryHdr *to);
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_DHashClearEntryStub(JSDHashTable *table, JSDHashEntryHdr *entry);
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_DHashFreeStringKey(JSDHashTable *table, JSDHashEntryHdr *entry);
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_DHashFinalizeStub(JSDHashTable *table);
|
|
|
|
/*
|
|
* If you use JSDHashEntryStub or a subclass of it as your entry struct, and
|
|
* if your entries move via memcpy and clear via memset(0), you can use these
|
|
* stub operations.
|
|
*/
|
|
extern JS_PUBLIC_API(const JSDHashTableOps *)
|
|
JS_DHashGetStubOps(void);
|
|
|
|
/*
|
|
* Dynamically allocate a new JSDHashTable using malloc, initialize it using
|
|
* JS_DHashTableInit, and return its address. Return null on malloc failure.
|
|
* Note that the entry storage at table->entryStore will be allocated using
|
|
* the ops->allocTable callback.
|
|
*/
|
|
extern JS_PUBLIC_API(JSDHashTable *)
|
|
JS_NewDHashTable(const JSDHashTableOps *ops, void *data, uint32_t entrySize,
|
|
uint32_t capacity);
|
|
|
|
/*
|
|
* Finalize table's data, free its entry storage (via table->ops->freeTable),
|
|
* and return the memory starting at table to the malloc heap.
|
|
*/
|
|
extern JS_PUBLIC_API(void)
|
|
JS_DHashTableDestroy(JSDHashTable *table);
|
|
|
|
/*
|
|
* Initialize table with ops, data, entrySize, and capacity. Capacity is a
|
|
* guess for the smallest table size at which the table will usually be less
|
|
* than 75% loaded (the table will grow or shrink as needed; capacity serves
|
|
* only to avoid inevitable early growth from JS_DHASH_MIN_SIZE).
|
|
*/
|
|
extern JS_PUBLIC_API(JSBool)
|
|
JS_DHashTableInit(JSDHashTable *table, const JSDHashTableOps *ops, void *data,
|
|
uint32_t entrySize, uint32_t capacity);
|
|
|
|
/*
|
|
* Set maximum and minimum alpha for table. The defaults are 0.75 and .25.
|
|
* maxAlpha must be in [0.5, 0.9375] for the default JS_DHASH_MIN_SIZE; or if
|
|
* MinSize=JS_DHASH_MIN_SIZE <= 256, in [0.5, (float)(MinSize-1)/MinSize]; or
|
|
* else in [0.5, 255.0/256]. minAlpha must be in [0, maxAlpha / 2), so that
|
|
* we don't shrink on the very next remove after growing a table upon adding
|
|
* an entry that brings entryCount past maxAlpha * tableSize.
|
|
*/
|
|
extern JS_PUBLIC_API(void)
|
|
JS_DHashTableSetAlphaBounds(JSDHashTable *table,
|
|
float maxAlpha,
|
|
float minAlpha);
|
|
|
|
/*
|
|
* Call this macro with k, the number of pointer-sized words wasted per entry
|
|
* under chaining, to compute the minimum alpha at which double hashing still
|
|
* beats chaining.
|
|
*/
|
|
#define JS_DHASH_MIN_ALPHA(table, k) \
|
|
((float)((table)->entrySize / sizeof(void *) - 1) \
|
|
/ ((table)->entrySize / sizeof(void *) + (k)))
|
|
|
|
/*
|
|
* Default max/min alpha, and macros to compute the value for the |capacity|
|
|
* parameter to JS_NewDHashTable and JS_DHashTableInit, given default or any
|
|
* max alpha, such that adding entryCount entries right after initializing the
|
|
* table will not require a reallocation (so JS_DHASH_ADD can't fail for those
|
|
* JS_DHashTableOperate calls).
|
|
*
|
|
* NB: JS_DHASH_CAP is a helper macro meant for use only in JS_DHASH_CAPACITY.
|
|
* Don't use it directly!
|
|
*/
|
|
#define JS_DHASH_DEFAULT_MAX_ALPHA 0.75
|
|
#define JS_DHASH_DEFAULT_MIN_ALPHA 0.25
|
|
|
|
#define JS_DHASH_CAP(entryCount, maxAlpha) \
|
|
((uint32_t)((double)(entryCount) / (maxAlpha)))
|
|
|
|
#define JS_DHASH_CAPACITY(entryCount, maxAlpha) \
|
|
(JS_DHASH_CAP(entryCount, maxAlpha) + \
|
|
(((JS_DHASH_CAP(entryCount, maxAlpha) * (uint8_t)(0x100 * (maxAlpha))) \
|
|
>> 8) < (entryCount)))
|
|
|
|
#define JS_DHASH_DEFAULT_CAPACITY(entryCount) \
|
|
JS_DHASH_CAPACITY(entryCount, JS_DHASH_DEFAULT_MAX_ALPHA)
|
|
|
|
/*
|
|
* Finalize table's data, free its entry storage using table->ops->freeTable,
|
|
* and leave its members unchanged from their last live values (which leaves
|
|
* pointers dangling). If you want to burn cycles clearing table, it's up to
|
|
* your code to call memset.
|
|
*/
|
|
extern JS_PUBLIC_API(void)
|
|
JS_DHashTableFinish(JSDHashTable *table);
|
|
|
|
/*
|
|
* To consolidate keyHash computation and table grow/shrink code, we use a
|
|
* single entry point for lookup, add, and remove operations. The operation
|
|
* codes are declared here, along with codes returned by JSDHashEnumerator
|
|
* functions, which control JS_DHashTableEnumerate's behavior.
|
|
*/
|
|
typedef enum JSDHashOperator {
|
|
JS_DHASH_LOOKUP = 0, /* lookup entry */
|
|
JS_DHASH_ADD = 1, /* add entry */
|
|
JS_DHASH_REMOVE = 2, /* remove entry, or enumerator says remove */
|
|
JS_DHASH_NEXT = 0, /* enumerator says continue */
|
|
JS_DHASH_STOP = 1 /* enumerator says stop */
|
|
} JSDHashOperator;
|
|
|
|
/*
|
|
* To lookup a key in table, call:
|
|
*
|
|
* entry = JS_DHashTableOperate(table, key, JS_DHASH_LOOKUP);
|
|
*
|
|
* If JS_DHASH_ENTRY_IS_BUSY(entry) is true, key was found and it identifies
|
|
* entry. If JS_DHASH_ENTRY_IS_FREE(entry) is true, key was not found.
|
|
*
|
|
* To add an entry identified by key to table, call:
|
|
*
|
|
* entry = JS_DHashTableOperate(table, key, JS_DHASH_ADD);
|
|
*
|
|
* If entry is null upon return, then either the table is severely overloaded,
|
|
* and memory can't be allocated for entry storage via table->ops->allocTable;
|
|
* Or if table->ops->initEntry is non-null, the table->ops->initEntry op may
|
|
* have returned false.
|
|
*
|
|
* Otherwise, entry->keyHash has been set so that JS_DHASH_ENTRY_IS_BUSY(entry)
|
|
* is true, and it is up to the caller to initialize the key and value parts
|
|
* of the entry sub-type, if they have not been set already (i.e. if entry was
|
|
* not already in the table, and if the optional initEntry hook was not used).
|
|
*
|
|
* To remove an entry identified by key from table, call:
|
|
*
|
|
* (void) JS_DHashTableOperate(table, key, JS_DHASH_REMOVE);
|
|
*
|
|
* If key's entry is found, it is cleared (via table->ops->clearEntry) and
|
|
* the entry is marked so that JS_DHASH_ENTRY_IS_FREE(entry). This operation
|
|
* returns null unconditionally; you should ignore its return value.
|
|
*/
|
|
extern JS_PUBLIC_API(JSDHashEntryHdr *) JS_DHASH_FASTCALL
|
|
JS_DHashTableOperate(JSDHashTable *table, const void *key, JSDHashOperator op);
|
|
|
|
/*
|
|
* Remove an entry already accessed via LOOKUP or ADD.
|
|
*
|
|
* NB: this is a "raw" or low-level routine, intended to be used only where
|
|
* the inefficiency of a full JS_DHashTableOperate (which rehashes in order
|
|
* to find the entry given its key) is not tolerable. This function does not
|
|
* shrink the table if it is underloaded. It does not update stats #ifdef
|
|
* JS_DHASHMETER, either.
|
|
*/
|
|
extern JS_PUBLIC_API(void)
|
|
JS_DHashTableRawRemove(JSDHashTable *table, JSDHashEntryHdr *entry);
|
|
|
|
/*
|
|
* Enumerate entries in table using etor:
|
|
*
|
|
* count = JS_DHashTableEnumerate(table, etor, arg);
|
|
*
|
|
* JS_DHashTableEnumerate calls etor like so:
|
|
*
|
|
* op = etor(table, entry, number, arg);
|
|
*
|
|
* where number is a zero-based ordinal assigned to live entries according to
|
|
* their order in table->entryStore.
|
|
*
|
|
* The return value, op, is treated as a set of flags. If op is JS_DHASH_NEXT,
|
|
* then continue enumerating. If op contains JS_DHASH_REMOVE, then clear (via
|
|
* table->ops->clearEntry) and free entry. Then we check whether op contains
|
|
* JS_DHASH_STOP; if so, stop enumerating and return the number of live entries
|
|
* that were enumerated so far. Return the total number of live entries when
|
|
* enumeration completes normally.
|
|
*
|
|
* If etor calls JS_DHashTableOperate on table with op != JS_DHASH_LOOKUP, it
|
|
* must return JS_DHASH_STOP; otherwise undefined behavior results.
|
|
*
|
|
* If any enumerator returns JS_DHASH_REMOVE, table->entryStore may be shrunk
|
|
* or compressed after enumeration, but before JS_DHashTableEnumerate returns.
|
|
* Such an enumerator therefore can't safely set aside entry pointers, but an
|
|
* enumerator that never returns JS_DHASH_REMOVE can set pointers to entries
|
|
* aside, e.g., to avoid copying live entries into an array of the entry type.
|
|
* Copying entry pointers is cheaper, and safe so long as the caller of such a
|
|
* "stable" Enumerate doesn't use the set-aside pointers after any call either
|
|
* to PL_DHashTableOperate, or to an "unstable" form of Enumerate, which might
|
|
* grow or shrink entryStore.
|
|
*
|
|
* If your enumerator wants to remove certain entries, but set aside pointers
|
|
* to other entries that it retains, it can use JS_DHashTableRawRemove on the
|
|
* entries to be removed, returning JS_DHASH_NEXT to skip them. Likewise, if
|
|
* you want to remove entries, but for some reason you do not want entryStore
|
|
* to be shrunk or compressed, you can call JS_DHashTableRawRemove safely on
|
|
* the entry being enumerated, rather than returning JS_DHASH_REMOVE.
|
|
*/
|
|
typedef JSDHashOperator
|
|
(* JSDHashEnumerator)(JSDHashTable *table, JSDHashEntryHdr *hdr, uint32_t number, void *arg);
|
|
|
|
extern JS_PUBLIC_API(uint32_t)
|
|
JS_DHashTableEnumerate(JSDHashTable *table, JSDHashEnumerator etor, void *arg);
|
|
|
|
typedef size_t
|
|
(* JSDHashSizeOfEntryExcludingThisFun)(JSDHashEntryHdr *hdr,
|
|
JSMallocSizeOfFun mallocSizeOf,
|
|
void *arg);
|
|
|
|
/**
|
|
* Measure the size of the table's entry storage, and if
|
|
* |sizeOfEntryExcludingThis| is non-NULL, measure the size of things pointed
|
|
* to by entries. Doesn't measure |ops| because it's often shared between
|
|
* tables, nor |data| because it's opaque.
|
|
*/
|
|
extern JS_PUBLIC_API(size_t)
|
|
JS_DHashTableSizeOfExcludingThis(const JSDHashTable *table,
|
|
JSDHashSizeOfEntryExcludingThisFun sizeOfEntryExcludingThis,
|
|
JSMallocSizeOfFun mallocSizeOf,
|
|
void *arg = NULL);
|
|
|
|
/**
|
|
* Like JS_DHashTableSizeOfExcludingThis, but includes sizeof(*this).
|
|
*/
|
|
extern JS_PUBLIC_API(size_t)
|
|
JS_DHashTableSizeOfIncludingThis(const JSDHashTable *table,
|
|
JSDHashSizeOfEntryExcludingThisFun sizeOfEntryExcludingThis,
|
|
JSMallocSizeOfFun mallocSizeOf,
|
|
void *arg = NULL);
|
|
|
|
#ifdef DEBUG
|
|
/**
|
|
* Mark a table as immutable for the remainder of its lifetime. This
|
|
* changes the implementation from ASSERTing one set of invariants to
|
|
* ASSERTing a different set.
|
|
*
|
|
* When a table is NOT marked as immutable, the table implementation
|
|
* asserts that the table is not mutated from its own callbacks. It
|
|
* assumes the caller protects the table from being accessed on multiple
|
|
* threads simultaneously.
|
|
*
|
|
* When the table is marked as immutable, the re-entry assertions will
|
|
* no longer trigger erroneously due to multi-threaded access. Instead,
|
|
* mutations will cause assertions.
|
|
*/
|
|
extern JS_PUBLIC_API(void)
|
|
JS_DHashMarkTableImmutable(JSDHashTable *table);
|
|
#endif
|
|
|
|
#ifdef JS_DHASHMETER
|
|
#include <stdio.h>
|
|
|
|
extern JS_PUBLIC_API(void)
|
|
JS_DHashTableDumpMeter(JSDHashTable *table, JSDHashEnumerator dump, FILE *fp);
|
|
#endif
|
|
|
|
#endif /* jsdhash_h___ */
|