The Tor Browser: modules/libpref/src/prefapi.cpp@6474c204b198 (annotated)

modules/libpref/src/prefapi.cpp@6474c204b198 (annotated)

modules/libpref/src/prefapi.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- 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 "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 "pldhash.h"
 #include "plbase64.h"
 #include "prlog.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 = { nullptr };
 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 = {
     PL_DHashAllocTable,
     PL_DHashFreeTable,
     PL_DHashStringKey,
     matchPrefEntry,
     PL_DHashMoveEntryStub,
     clearPrefEntry,
     PL_DHashFinalizeStub,
     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
 };
 static nsresult pref_HashPref(const char *key, PrefValue value, PrefType type, uint32_t flags);
 #define PREF_HASHTABLE_INITIAL_SIZE	2048
 nsresult PREF_Init()
 {
     if (!gHashTable.ops) {
         if (!PL_DHashTableInit(&gHashTable, &pref_HashTableOps, nullptr,
                                sizeof(PrefHashEntry), PREF_HASHTABLE_INITIAL_SIZE,
                                fallible_t())) {
             gHashTable.ops = nullptr;
             return NS_ERROR_OUT_OF_MEMORY;
         }
         PL_INIT_ARENA_POOL(&gPrefNameArena, "PrefNameArena",
                            PREFNAME_ARENA_SIZE);
     }
     return NS_OK;
 }
 /* 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.ops) {
         PL_DHashTableFinish(&gHashTable);
         gHashTable.ops = 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.Append("\\n");
                 break;
             case '\r':
                 aResult.Append("\\r");
                 break;
             case '\\':
                 aResult.Append("\\\\");
                 break;
             case '\"':
                 aResult.Append("\\\"");
                 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;
 }
 PLDHashOperator
 pref_savePref(PLDHashTable *table, PLDHashEntryHdr *heh, uint32_t i, void *arg)
 {
     pref_saveArgs *argData = static_cast<pref_saveArgs *>(arg);
     PrefHashEntry *pref = static_cast<PrefHashEntry *>(heh);
     PR_ASSERT(pref);
     if (!pref)
         return PL_DHASH_NEXT;
     nsAutoCString prefValue;
     nsAutoCString prefPrefix;
     prefPrefix.Assign(NS_LITERAL_CSTRING("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))) {
         sourcePref = &pref->userPref;
     } else {
         if (argData->saveTypes == SAVE_ALL_AND_DEFAULTS) {
             prefPrefix.Assign(NS_LITERAL_CSTRING("pref(\""));
             sourcePref = &pref->defaultPref;
         }
         else
             // do not save default prefs that haven't changed
             return PL_DHASH_NEXT;
     }
     // 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);
     argData->prefArray[i] = ToNewCString(prefPrefix +
                                          prefName +
                                          NS_LITERAL_CSTRING("\", ") +
                                          prefValue +
                                          NS_LITERAL_CSTRING(");"));
     return PL_DHASH_NEXT;
 }
 PLDHashOperator
 pref_GetPrefs(PLDHashTable *table,
               PLDHashEntryHdr *heh,
               uint32_t i,
               void *arg)
 {
     if (heh) {
         PrefHashEntry *entry = static_cast<PrefHashEntry *>(heh);
         dom::PrefSetting *pref =
             static_cast<InfallibleTArray<dom::PrefSetting>*>(arg)->AppendElement();
         pref_GetPrefFromEntry(entry, pref);
     }
     return PL_DHASH_NEXT;
 }
 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.ops)
         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.ops)
         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.ops)
         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.ops)
         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;
 }
 /* Delete a branch. Used for deleting mime types */
 static PLDHashOperator
 pref_DeleteItem(PLDHashTable *table, PLDHashEntryHdr *heh, uint32_t i, void *arg)
 {
     PrefHashEntry* he = static_cast<PrefHashEntry*>(heh);
     const char *to_delete = (const char *) arg;
     int len = strlen(to_delete);
     /* 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 (to_delete && (PL_strncmp(he->key, to_delete, (uint32_t) len) == 0 ||
         (len-1 == (int)strlen(he->key) && PL_strncmp(he->key, to_delete, (uint32_t)(len-1)) == 0)))
         return PL_DHASH_REMOVE;
     return PL_DHASH_NEXT;
 }
 nsresult
 PREF_DeleteBranch(const char *branch_name)
 {
 #ifndef MOZ_B2G
     MOZ_ASSERT(NS_IsMainThread());
 #endif
     int len = (int)strlen(branch_name);
     if (!gHashTable.ops)
         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 += '.';
     PL_DHashTableEnumerate(&gHashTable, pref_DeleteItem,
                            (void*) branch_dot.get());
     gDirty = true;
     return NS_OK;
 }
 nsresult
 PREF_ClearUserPref(const char *pref_name)
 {
     if (!gHashTable.ops)
         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)) {
             PL_DHashTableOperate(&gHashTable, pref_name, PL_DHASH_REMOVE);
         }
         pref_DoCallback(pref_name);
         gDirty = true;
     }
     return NS_OK;
 }
 static PLDHashOperator
 pref_ClearUserPref(PLDHashTable *table, PLDHashEntryHdr *he, uint32_t,
                    void *arg)
 {
     PrefHashEntry *pref = static_cast<PrefHashEntry*>(he);
     PLDHashOperator nextOp = PL_DHASH_NEXT;
     if (PREF_HAS_USER_VALUE(pref))
     {
         pref->flags &= ~PREF_USERSET;
         if (!(pref->flags & PREF_HAS_DEFAULT)) {
             nextOp = PL_DHASH_REMOVE;
         }
         pref_DoCallback(pref->key);
     }
     return nextOp;
 }
 nsresult
 PREF_ClearAllUserPrefs()
 {
 #ifndef MOZ_B2G
     MOZ_ASSERT(NS_IsMainThread());
 #endif
     if (!gHashTable.ops)
         return NS_ERROR_NOT_INITIALIZED;
     PL_DHashTableEnumerate(&gHashTable, pref_ClearUserPref, nullptr);
     gDirty = true;
     return NS_OK;
 }
 nsresult PREF_LockPref(const char *key, bool lockit)
 {
     if (!gHashTable.ops)
         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;
     }
     gDirty = true;
 }
 PrefHashEntry* pref_HashTableLookup(const void *key)
 {
 #ifndef MOZ_B2G
     MOZ_ASSERT(NS_IsMainThread());
 #endif
     PrefHashEntry* result =
         static_cast<PrefHashEntry*>(PL_DHashTableOperate(&gHashTable, key, PL_DHASH_LOOKUP));
     if (PL_DHASH_ENTRY_IS_FREE(result))
         return nullptr;
     return result;
 }
 nsresult pref_HashPref(const char *key, PrefValue value, PrefType type, uint32_t flags)
 {
 #ifndef MOZ_B2G
     MOZ_ASSERT(NS_IsMainThread());
 #endif
     if (!gHashTable.ops)
         return NS_ERROR_OUT_OF_MEMORY;
     PrefHashEntry* pref = static_cast<PrefHashEntry*>(PL_DHashTableOperate(&gHashTable, key, PL_DHASH_ADD));
     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 (!PREF_HAS_USER_VALUE(pref))
                     valueChanged = true;
             }
         }
     }
     else
     {
         /* If new value is same as the default value, then un-set the user value.
            Otherwise, set the user value only if it has changed */
         if ((pref->flags & PREF_HAS_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))
                     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))
                 valueChanged = true;
         }
     }
     nsresult rv = NS_OK;
     if (valueChanged) {
         gDirty = true;
         nsresult rv2 = pref_DoCallback(key);
         if (NS_FAILED(rv2))
             rv = rv2;
     }
     return rv;
 }
 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.ops)
     {
         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.ops) {
         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)
 {
     pref_HashPref(pref, value, type, isDefault ? kPrefSetDefault : kPrefForceSet);
 }

The Tor Browser / annotate

modules/libpref/src/prefapi.cpp@6474c204b198 (annotated)

modules/libpref/src/prefapi.cpp