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gecko-dev/modules/libpref/prefapi.cpp

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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/. */
#include <string>
#include <vector>
#include "base/basictypes.h"
#include "prefapi.h"
#include "prefapi_private_data.h"
#include "prefread.h"
#include "MainThreadUtils.h"
#include "nsReadableUtils.h"
#include "nsCRT.h"
#define PL_ARENA_CONST_ALIGN_MASK 3
#include "plarena.h"
#ifdef _WIN32
#include "windows.h"
#endif /* _WIN32 */
#include "plstr.h"
#include "PLDHashTable.h"
#include "plbase64.h"
#include "mozilla/Logging.h"
#include "prprf.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/dom/PContent.h"
#include "nsQuickSort.h"
#include "nsString.h"
#include "nsPrintfCString.h"
#include "prlink.h"
using namespace mozilla;
static void
clearPrefEntry(PLDHashTable *table, PLDHashEntryHdr *entry)
{
PrefHashEntry *pref = static_cast<PrefHashEntry *>(entry);
if (pref->flags & PREF_STRING)
{
if (pref->defaultPref.stringVal)
PL_strfree(pref->defaultPref.stringVal);
if (pref->userPref.stringVal)
PL_strfree(pref->userPref.stringVal);
}
// don't need to free this as it's allocated in memory owned by
// gPrefNameArena
pref->key = nullptr;
memset(entry, 0, table->EntrySize());
}
static bool
matchPrefEntry(PLDHashTable*, const PLDHashEntryHdr* entry,
const void* key)
{
const PrefHashEntry *prefEntry =
static_cast<const PrefHashEntry*>(entry);
if (prefEntry->key == key) return true;
if (!prefEntry->key || !key) return false;
const char *otherKey = reinterpret_cast<const char*>(key);
return (strcmp(prefEntry->key, otherKey) == 0);
}
PLDHashTable* gHashTable;
static PLArenaPool gPrefNameArena;
bool gDirty = false;
static struct CallbackNode* gCallbacks = nullptr;
static bool gIsAnyPrefLocked = false;
// These are only used during the call to pref_DoCallback
static bool gCallbacksInProgress = false;
static bool gShouldCleanupDeadNodes = false;
static PLDHashTableOps pref_HashTableOps = {
PLDHashTable::HashStringKey,
matchPrefEntry,
PLDHashTable::MoveEntryStub,
clearPrefEntry,
nullptr,
};
// PR_ALIGN_OF_WORD is only defined on some platforms. ALIGN_OF_WORD has
// already been defined to PR_ALIGN_OF_WORD everywhere
#ifndef PR_ALIGN_OF_WORD
#define PR_ALIGN_OF_WORD PR_ALIGN_OF_POINTER
#endif
// making PrefName arena 8k for nice allocation
#define PREFNAME_ARENA_SIZE 8192
#define WORD_ALIGN_MASK (PR_ALIGN_OF_WORD - 1)
// sanity checking
#if (PR_ALIGN_OF_WORD & WORD_ALIGN_MASK) != 0
#error "PR_ALIGN_OF_WORD must be a power of 2!"
#endif
// equivalent to strdup() - does no error checking,
// we're assuming we're only called with a valid pointer
static char *ArenaStrDup(const char* str, PLArenaPool* aArena)
{
void* mem;
uint32_t len = strlen(str);
PL_ARENA_ALLOCATE(mem, aArena, len+1);
if (mem)
memcpy(mem, str, len+1);
return static_cast<char*>(mem);
}
/*---------------------------------------------------------------------------*/
#define PREF_IS_LOCKED(pref) ((pref)->flags & PREF_LOCKED)
#define PREF_HAS_DEFAULT_VALUE(pref) ((pref)->flags & PREF_HAS_DEFAULT)
#define PREF_HAS_USER_VALUE(pref) ((pref)->flags & PREF_USERSET)
#define PREF_TYPE(pref) (PrefType)((pref)->flags & PREF_VALUETYPE_MASK)
static bool pref_ValueChanged(PrefValue oldValue, PrefValue newValue, PrefType type);
/* -- Privates */
struct CallbackNode {
char* domain;
// If someone attempts to remove the node from the callback list while
// pref_DoCallback is running, |func| is set to nullptr. Such nodes will
// be removed at the end of pref_DoCallback.
PrefChangedFunc func;
void* data;
struct CallbackNode* next;
};
/* -- Prototypes */
static nsresult pref_DoCallback(const char* changed_pref);
enum {
kPrefSetDefault = 1,
kPrefForceSet = 2,
kPrefStickyDefault = 4,
};
static nsresult pref_HashPref(const char *key, PrefValue value, PrefType type, uint32_t flags);
#define PREF_HASHTABLE_INITIAL_LENGTH 1024
void PREF_Init()
{
if (!gHashTable) {
gHashTable = new PLDHashTable(&pref_HashTableOps,
sizeof(PrefHashEntry),
PREF_HASHTABLE_INITIAL_LENGTH);
PL_INIT_ARENA_POOL(&gPrefNameArena, "PrefNameArena",
PREFNAME_ARENA_SIZE);
}
}
/* Frees the callback list. */
void PREF_Cleanup()
{
NS_ASSERTION(!gCallbacksInProgress,
"PREF_Cleanup was called while gCallbacksInProgress is true!");
struct CallbackNode* node = gCallbacks;
struct CallbackNode* next_node;
while (node)
{
next_node = node->next;
PL_strfree(node->domain);
free(node);
node = next_node;
}
gCallbacks = nullptr;
PREF_CleanupPrefs();
}
/* Frees up all the objects except the callback list. */
void PREF_CleanupPrefs()
{
if (gHashTable) {
delete gHashTable;
gHashTable = nullptr;
PL_FinishArenaPool(&gPrefNameArena);
}
}
// note that this appends to aResult, and does not assign!
static void str_escape(const char * original, nsAFlatCString& aResult)
{
/* JavaScript does not allow quotes, slashes, or line terminators inside
* strings so we must escape them. ECMAScript defines four line
* terminators, but we're only worrying about \r and \n here. We currently
* feed our pref script to the JS interpreter as Latin-1 so we won't
* encounter \u2028 (line separator) or \u2029 (paragraph separator).
*
* WARNING: There are hints that we may be moving to storing prefs
* as utf8. If we ever feed them to the JS compiler as UTF8 then
* we'll have to worry about the multibyte sequences that would be
* interpreted as \u2028 and \u2029
*/
const char *p;
if (original == nullptr)
return;
/* Paranoid worst case all slashes will free quickly */
for (p=original; *p; ++p)
{
switch (*p)
{
case '\n':
aResult.AppendLiteral("\\n");
break;
case '\r':
aResult.AppendLiteral("\\r");
break;
case '\\':
aResult.AppendLiteral("\\\\");
break;
case '\"':
aResult.AppendLiteral("\\\"");
break;
default:
aResult.Append(*p);
break;
}
}
}
/*
** External calls
*/
nsresult
PREF_SetCharPref(const char *pref_name, const char *value, bool set_default)
{
if ((uint32_t)strlen(value) > MAX_PREF_LENGTH) {
return NS_ERROR_ILLEGAL_VALUE;
}
PrefValue pref;
pref.stringVal = (char*)value;
return pref_HashPref(pref_name, pref, PREF_STRING, set_default ? kPrefSetDefault : 0);
}
nsresult
PREF_SetIntPref(const char *pref_name, int32_t value, bool set_default)
{
PrefValue pref;
pref.intVal = value;
return pref_HashPref(pref_name, pref, PREF_INT, set_default ? kPrefSetDefault : 0);
}
nsresult
PREF_SetBoolPref(const char *pref_name, bool value, bool set_default)
{
PrefValue pref;
pref.boolVal = value;
return pref_HashPref(pref_name, pref, PREF_BOOL, set_default ? kPrefSetDefault : 0);
}
enum WhichValue { DEFAULT_VALUE, USER_VALUE };
static nsresult
SetPrefValue(const char* aPrefName, const dom::PrefValue& aValue,
WhichValue aWhich)
{
bool setDefault = (aWhich == DEFAULT_VALUE);
switch (aValue.type()) {
case dom::PrefValue::TnsCString:
return PREF_SetCharPref(aPrefName, aValue.get_nsCString().get(),
setDefault);
case dom::PrefValue::Tint32_t:
return PREF_SetIntPref(aPrefName, aValue.get_int32_t(),
setDefault);
case dom::PrefValue::Tbool:
return PREF_SetBoolPref(aPrefName, aValue.get_bool(),
setDefault);
default:
MOZ_CRASH();
}
}
nsresult
pref_SetPref(const dom::PrefSetting& aPref)
{
const char* prefName = aPref.name().get();
const dom::MaybePrefValue& defaultValue = aPref.defaultValue();
const dom::MaybePrefValue& userValue = aPref.userValue();
nsresult rv;
if (defaultValue.type() == dom::MaybePrefValue::TPrefValue) {
rv = SetPrefValue(prefName, defaultValue.get_PrefValue(), DEFAULT_VALUE);
if (NS_FAILED(rv)) {
return rv;
}
}
if (userValue.type() == dom::MaybePrefValue::TPrefValue) {
rv = SetPrefValue(prefName, userValue.get_PrefValue(), USER_VALUE);
} else {
rv = PREF_ClearUserPref(prefName);
}
// NB: we should never try to clear a default value, that doesn't
// make sense
return rv;
}
void
pref_savePrefs(PLDHashTable* aTable, char** aPrefArray)
{
int32_t j = 0;
for (auto iter = aTable->Iter(); !iter.Done(); iter.Next()) {
auto pref = static_cast<PrefHashEntry*>(iter.Get());
nsAutoCString prefValue;
nsAutoCString prefPrefix;
prefPrefix.AssignLiteral("user_pref(\"");
// where we're getting our pref from
PrefValue* sourcePref;
if (PREF_HAS_USER_VALUE(pref) &&
(pref_ValueChanged(pref->defaultPref,
pref->userPref,
(PrefType) PREF_TYPE(pref)) ||
!(pref->flags & PREF_HAS_DEFAULT) ||
pref->flags & PREF_STICKY_DEFAULT)) {
sourcePref = &pref->userPref;
} else {
// do not save default prefs that haven't changed
continue;
}
// strings are in quotes!
if (pref->flags & PREF_STRING) {
prefValue = '\"';
str_escape(sourcePref->stringVal, prefValue);
prefValue += '\"';
} else if (pref->flags & PREF_INT) {
prefValue.AppendInt(sourcePref->intVal);
} else if (pref->flags & PREF_BOOL) {
prefValue = (sourcePref->boolVal) ? "true" : "false";
}
nsAutoCString prefName;
str_escape(pref->key, prefName);
aPrefArray[j++] = ToNewCString(prefPrefix +
prefName +
NS_LITERAL_CSTRING("\", ") +
prefValue +
NS_LITERAL_CSTRING(");"));
}
}
static void
GetPrefValueFromEntry(PrefHashEntry *aHashEntry, dom::PrefSetting* aPref,
WhichValue aWhich)
{
PrefValue* value;
dom::PrefValue* settingValue;
if (aWhich == USER_VALUE) {
value = &aHashEntry->userPref;
aPref->userValue() = dom::PrefValue();
settingValue = &aPref->userValue().get_PrefValue();
} else {
value = &aHashEntry->defaultPref;
aPref->defaultValue() = dom::PrefValue();
settingValue = &aPref->defaultValue().get_PrefValue();
}
switch (aHashEntry->flags & PREF_VALUETYPE_MASK) {
case PREF_STRING:
*settingValue = nsDependentCString(value->stringVal);
return;
case PREF_INT:
*settingValue = value->intVal;
return;
case PREF_BOOL:
*settingValue = !!value->boolVal;
return;
default:
MOZ_CRASH();
}
}
void
pref_GetPrefFromEntry(PrefHashEntry *aHashEntry, dom::PrefSetting* aPref)
{
aPref->name() = aHashEntry->key;
if (PREF_HAS_DEFAULT_VALUE(aHashEntry)) {
GetPrefValueFromEntry(aHashEntry, aPref, DEFAULT_VALUE);
} else {
aPref->defaultValue() = null_t();
}
if (PREF_HAS_USER_VALUE(aHashEntry)) {
GetPrefValueFromEntry(aHashEntry, aPref, USER_VALUE);
} else {
aPref->userValue() = null_t();
}
MOZ_ASSERT(aPref->defaultValue().type() == dom::MaybePrefValue::Tnull_t ||
aPref->userValue().type() == dom::MaybePrefValue::Tnull_t ||
(aPref->defaultValue().get_PrefValue().type() ==
aPref->userValue().get_PrefValue().type()));
}
int
pref_CompareStrings(const void *v1, const void *v2, void *unused)
{
char *s1 = *(char**) v1;
char *s2 = *(char**) v2;
if (!s1)
{
if (!s2)
return 0;
else
return -1;
}
else if (!s2)
return 1;
else
return strcmp(s1, s2);
}
bool PREF_HasUserPref(const char *pref_name)
{
if (!gHashTable)
return false;
PrefHashEntry *pref = pref_HashTableLookup(pref_name);
if (!pref) return false;
/* convert PREF_HAS_USER_VALUE to bool */
return (PREF_HAS_USER_VALUE(pref) != 0);
}
nsresult
PREF_CopyCharPref(const char *pref_name, char ** return_buffer, bool get_default)
{
if (!gHashTable)
return NS_ERROR_NOT_INITIALIZED;
nsresult rv = NS_ERROR_UNEXPECTED;
char* stringVal;
PrefHashEntry* pref = pref_HashTableLookup(pref_name);
if (pref && (pref->flags & PREF_STRING))
{
if (get_default || PREF_IS_LOCKED(pref) || !PREF_HAS_USER_VALUE(pref))
stringVal = pref->defaultPref.stringVal;
else
stringVal = pref->userPref.stringVal;
if (stringVal) {
*return_buffer = NS_strdup(stringVal);
rv = NS_OK;
}
}
return rv;
}
nsresult PREF_GetIntPref(const char *pref_name,int32_t * return_int, bool get_default)
{
if (!gHashTable)
return NS_ERROR_NOT_INITIALIZED;
nsresult rv = NS_ERROR_UNEXPECTED;
PrefHashEntry* pref = pref_HashTableLookup(pref_name);
if (pref && (pref->flags & PREF_INT))
{
if (get_default || PREF_IS_LOCKED(pref) || !PREF_HAS_USER_VALUE(pref))
{
int32_t tempInt = pref->defaultPref.intVal;
/* check to see if we even had a default */
if (!(pref->flags & PREF_HAS_DEFAULT))
return NS_ERROR_UNEXPECTED;
*return_int = tempInt;
}
else
*return_int = pref->userPref.intVal;
rv = NS_OK;
}
return rv;
}
nsresult PREF_GetBoolPref(const char *pref_name, bool * return_value, bool get_default)
{
if (!gHashTable)
return NS_ERROR_NOT_INITIALIZED;
nsresult rv = NS_ERROR_UNEXPECTED;
PrefHashEntry* pref = pref_HashTableLookup(pref_name);
//NS_ASSERTION(pref, pref_name);
if (pref && (pref->flags & PREF_BOOL))
{
if (get_default || PREF_IS_LOCKED(pref) || !PREF_HAS_USER_VALUE(pref))
{
bool tempBool = pref->defaultPref.boolVal;
/* check to see if we even had a default */
if (pref->flags & PREF_HAS_DEFAULT) {
*return_value = tempBool;
rv = NS_OK;
}
}
else {
*return_value = pref->userPref.boolVal;
rv = NS_OK;
}
}
return rv;
}
nsresult
PREF_DeleteBranch(const char *branch_name)
{
#ifndef MOZ_B2G
MOZ_ASSERT(NS_IsMainThread());
#endif
int len = (int)strlen(branch_name);
if (!gHashTable)
return NS_ERROR_NOT_INITIALIZED;
/* The following check insures that if the branch name already has a "."
* at the end, we don't end up with a "..". This fixes an incompatibility
* between nsIPref, which needs the period added, and nsIPrefBranch which
* does not. When nsIPref goes away this function should be fixed to
* never add the period at all.
*/
nsAutoCString branch_dot(branch_name);
if ((len > 1) && branch_name[len - 1] != '.')
branch_dot += '.';
/* Delete a branch. Used for deleting mime types */
const char *to_delete = branch_dot.get();
MOZ_ASSERT(to_delete);
len = strlen(to_delete);
for (auto iter = gHashTable->Iter(); !iter.Done(); iter.Next()) {
auto entry = static_cast<PrefHashEntry*>(iter.Get());
/* note if we're deleting "ldap" then we want to delete "ldap.xxx"
and "ldap" (if such a leaf node exists) but not "ldap_1.xxx" */
if (PL_strncmp(entry->key, to_delete, (uint32_t) len) == 0 ||
(len-1 == (int)strlen(entry->key) &&
PL_strncmp(entry->key, to_delete, (uint32_t)(len-1)) == 0)) {
iter.Remove();
}
}
gDirty = true;
return NS_OK;
}
nsresult
PREF_ClearUserPref(const char *pref_name)
{
if (!gHashTable)
return NS_ERROR_NOT_INITIALIZED;
PrefHashEntry* pref = pref_HashTableLookup(pref_name);
if (pref && PREF_HAS_USER_VALUE(pref))
{
pref->flags &= ~PREF_USERSET;
if (!(pref->flags & PREF_HAS_DEFAULT)) {
gHashTable->RemoveEntry(pref);
}
pref_DoCallback(pref_name);
gDirty = true;
}
return NS_OK;
}
nsresult
PREF_ClearAllUserPrefs()
{
#ifndef MOZ_B2G
MOZ_ASSERT(NS_IsMainThread());
#endif
if (!gHashTable)
return NS_ERROR_NOT_INITIALIZED;
std::vector<std::string> prefStrings;
for (auto iter = gHashTable->Iter(); !iter.Done(); iter.Next()) {
auto pref = static_cast<PrefHashEntry*>(iter.Get());
if (PREF_HAS_USER_VALUE(pref)) {
prefStrings.push_back(std::string(pref->key));
pref->flags &= ~PREF_USERSET;
if (!(pref->flags & PREF_HAS_DEFAULT)) {
iter.Remove();
}
}
}
for (std::string& prefString : prefStrings) {
pref_DoCallback(prefString.c_str());
}
gDirty = true;
return NS_OK;
}
nsresult PREF_LockPref(const char *key, bool lockit)
{
if (!gHashTable)
return NS_ERROR_NOT_INITIALIZED;
PrefHashEntry* pref = pref_HashTableLookup(key);
if (!pref)
return NS_ERROR_UNEXPECTED;
if (lockit) {
if (!PREF_IS_LOCKED(pref))
{
pref->flags |= PREF_LOCKED;
gIsAnyPrefLocked = true;
pref_DoCallback(key);
}
}
else
{
if (PREF_IS_LOCKED(pref))
{
pref->flags &= ~PREF_LOCKED;
pref_DoCallback(key);
}
}
return NS_OK;
}
/*
* Hash table functions
*/
static bool pref_ValueChanged(PrefValue oldValue, PrefValue newValue, PrefType type)
{
bool changed = true;
if (type & PREF_STRING)
{
if (oldValue.stringVal && newValue.stringVal)
changed = (strcmp(oldValue.stringVal, newValue.stringVal) != 0);
}
else if (type & PREF_INT)
changed = oldValue.intVal != newValue.intVal;
else if (type & PREF_BOOL)
changed = oldValue.boolVal != newValue.boolVal;
return changed;
}
/*
* Overwrite the type and value of an existing preference. Caller must
* ensure that they are not changing the type of a preference that has
* a default value.
*/
static void pref_SetValue(PrefValue* existingValue, uint16_t *existingFlags,
PrefValue newValue, PrefType newType)
{
if ((*existingFlags & PREF_STRING) && existingValue->stringVal) {
PL_strfree(existingValue->stringVal);
}
*existingFlags = (*existingFlags & ~PREF_VALUETYPE_MASK) | newType;
if (newType & PREF_STRING) {
PR_ASSERT(newValue.stringVal);
existingValue->stringVal = newValue.stringVal ? PL_strdup(newValue.stringVal) : nullptr;
}
else {
*existingValue = newValue;
}
}
PrefHashEntry* pref_HashTableLookup(const char *key)
{
#ifndef MOZ_B2G
MOZ_ASSERT(NS_IsMainThread());
#endif
return static_cast<PrefHashEntry*>(gHashTable->Search(key));
}
nsresult pref_HashPref(const char *key, PrefValue value, PrefType type, uint32_t flags)
{
#ifndef MOZ_B2G
MOZ_ASSERT(NS_IsMainThread());
#endif
if (!gHashTable)
return NS_ERROR_OUT_OF_MEMORY;
auto pref = static_cast<PrefHashEntry*>(gHashTable->Add(key, fallible));
if (!pref)
return NS_ERROR_OUT_OF_MEMORY;
// new entry, better initialize
if (!pref->key) {
// initialize the pref entry
pref->flags = type;
pref->key = ArenaStrDup(key, &gPrefNameArena);
memset(&pref->defaultPref, 0, sizeof(pref->defaultPref));
memset(&pref->userPref, 0, sizeof(pref->userPref));
}
else if ((pref->flags & PREF_HAS_DEFAULT) && PREF_TYPE(pref) != type)
{
NS_WARNING(nsPrintfCString("Trying to overwrite value of default pref %s with the wrong type!", key).get());
return NS_ERROR_UNEXPECTED;
}
bool valueChanged = false;
if (flags & kPrefSetDefault)
{
if (!PREF_IS_LOCKED(pref))
{ /* ?? change of semantics? */
if (pref_ValueChanged(pref->defaultPref, value, type) ||
!(pref->flags & PREF_HAS_DEFAULT))
{
pref_SetValue(&pref->defaultPref, &pref->flags, value, type);
pref->flags |= PREF_HAS_DEFAULT;
if (flags & kPrefStickyDefault)
pref->flags |= PREF_STICKY_DEFAULT;
if (!PREF_HAS_USER_VALUE(pref))
valueChanged = true;
}
// What if we change the default to be the same as the user value?
// Should we clear the user value?
}
}
else
{
/* If new value is same as the default value and it's not a "sticky"
pref, then un-set the user value.
Otherwise, set the user value only if it has changed */
if ((pref->flags & PREF_HAS_DEFAULT) &&
!(pref->flags & PREF_STICKY_DEFAULT) &&
!pref_ValueChanged(pref->defaultPref, value, type) &&
!(flags & kPrefForceSet))
{
if (PREF_HAS_USER_VALUE(pref))
{
/* XXX should we free a user-set string value if there is one? */
pref->flags &= ~PREF_USERSET;
if (!PREF_IS_LOCKED(pref)) {
gDirty = true;
valueChanged = true;
}
}
}
else if (!PREF_HAS_USER_VALUE(pref) ||
PREF_TYPE(pref) != type ||
pref_ValueChanged(pref->userPref, value, type) )
{
pref_SetValue(&pref->userPref, &pref->flags, value, type);
pref->flags |= PREF_USERSET;
if (!PREF_IS_LOCKED(pref)) {
gDirty = true;
valueChanged = true;
}
}
}
if (valueChanged) {
return pref_DoCallback(key);
}
return NS_OK;
}
size_t
pref_SizeOfPrivateData(MallocSizeOf aMallocSizeOf)
{
size_t n = PL_SizeOfArenaPoolExcludingPool(&gPrefNameArena, aMallocSizeOf);
for (struct CallbackNode* node = gCallbacks; node; node = node->next) {
n += aMallocSizeOf(node);
n += aMallocSizeOf(node->domain);
}
return n;
}
PrefType
PREF_GetPrefType(const char *pref_name)
{
if (gHashTable) {
PrefHashEntry* pref = pref_HashTableLookup(pref_name);
if (pref)
{
if (pref->flags & PREF_STRING)
return PREF_STRING;
else if (pref->flags & PREF_INT)
return PREF_INT;
else if (pref->flags & PREF_BOOL)
return PREF_BOOL;
}
}
return PREF_INVALID;
}
/* -- */
bool
PREF_PrefIsLocked(const char *pref_name)
{
bool result = false;
if (gIsAnyPrefLocked && gHashTable) {
PrefHashEntry* pref = pref_HashTableLookup(pref_name);
if (pref && PREF_IS_LOCKED(pref))
result = true;
}
return result;
}
/* Adds a node to the beginning of the callback list. */
void
PREF_RegisterCallback(const char *pref_node,
PrefChangedFunc callback,
void * instance_data)
{
NS_PRECONDITION(pref_node, "pref_node must not be nullptr");
NS_PRECONDITION(callback, "callback must not be nullptr");
struct CallbackNode* node = (struct CallbackNode*) malloc(sizeof(struct CallbackNode));
if (node)
{
node->domain = PL_strdup(pref_node);
node->func = callback;
node->data = instance_data;
node->next = gCallbacks;
gCallbacks = node;
}
return;
}
/* Removes |node| from gCallbacks list.
Returns the node after the deleted one. */
struct CallbackNode*
pref_RemoveCallbackNode(struct CallbackNode* node,
struct CallbackNode* prev_node)
{
NS_PRECONDITION(!prev_node || prev_node->next == node, "invalid params");
NS_PRECONDITION(prev_node || gCallbacks == node, "invalid params");
NS_ASSERTION(!gCallbacksInProgress,
"modifying the callback list while gCallbacksInProgress is true");
struct CallbackNode* next_node = node->next;
if (prev_node)
prev_node->next = next_node;
else
gCallbacks = next_node;
PL_strfree(node->domain);
free(node);
return next_node;
}
/* Deletes a node from the callback list or marks it for deletion. */
nsresult
PREF_UnregisterCallback(const char *pref_node,
PrefChangedFunc callback,
void * instance_data)
{
nsresult rv = NS_ERROR_FAILURE;
struct CallbackNode* node = gCallbacks;
struct CallbackNode* prev_node = nullptr;
while (node != nullptr)
{
if ( node->func == callback &&
node->data == instance_data &&
strcmp(node->domain, pref_node) == 0)
{
if (gCallbacksInProgress)
{
// postpone the node removal until after
// gCallbacks enumeration is finished.
node->func = nullptr;
gShouldCleanupDeadNodes = true;
prev_node = node;
node = node->next;
}
else
{
node = pref_RemoveCallbackNode(node, prev_node);
}
rv = NS_OK;
}
else
{
prev_node = node;
node = node->next;
}
}
return rv;
}
static nsresult pref_DoCallback(const char* changed_pref)
{
nsresult rv = NS_OK;
struct CallbackNode* node;
bool reentered = gCallbacksInProgress;
gCallbacksInProgress = true;
// Nodes must not be deleted while gCallbacksInProgress is true.
// Nodes that need to be deleted are marked for deletion by nulling
// out the |func| pointer. We release them at the end of this function
// if we haven't reentered.
for (node = gCallbacks; node != nullptr; node = node->next)
{
if ( node->func &&
PL_strncmp(changed_pref,
node->domain,
strlen(node->domain)) == 0 )
{
(*node->func) (changed_pref, node->data);
}
}
gCallbacksInProgress = reentered;
if (gShouldCleanupDeadNodes && !gCallbacksInProgress)
{
struct CallbackNode* prev_node = nullptr;
node = gCallbacks;
while (node != nullptr)
{
if (!node->func)
{
node = pref_RemoveCallbackNode(node, prev_node);
}
else
{
prev_node = node;
node = node->next;
}
}
gShouldCleanupDeadNodes = false;
}
return rv;
}
void PREF_ReaderCallback(void *closure,
const char *pref,
PrefValue value,
PrefType type,
bool isDefault,
bool isStickyDefault)
{
uint32_t flags = isDefault ? kPrefSetDefault : kPrefForceSet;
if (isDefault && isStickyDefault) {
flags |= kPrefStickyDefault;
}
pref_HashPref(pref, value, type, flags);
}
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