1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/modules/libpref/src/nsPrefBranch.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,266 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef nsPrefBranch_h
1.10 +#define nsPrefBranch_h
1.11 +
1.12 +#include "nsCOMPtr.h"
1.13 +#include "nsIObserver.h"
1.14 +#include "nsIPrefBranch.h"
1.15 +#include "nsIPrefBranchInternal.h"
1.16 +#include "nsIPrefLocalizedString.h"
1.17 +#include "nsXPCOM.h"
1.18 +#include "nsISupportsPrimitives.h"
1.19 +#include "nsIRelativeFilePref.h"
1.20 +#include "nsIFile.h"
1.21 +#include "nsString.h"
1.22 +#include "nsTArray.h"
1.23 +#include "nsWeakReference.h"
1.24 +#include "nsClassHashtable.h"
1.25 +#include "nsCRT.h"
1.26 +#include "nsISupportsImpl.h"
1.27 +#include "mozilla/HashFunctions.h"
1.28 +#include "mozilla/MemoryReporting.h"
1.29 +
1.30 +namespace mozilla {
1.31 +class PreferenceServiceReporter;
1.32 +} // namespace mozilla;
1.33 +
1.34 +class nsPrefBranch;
1.35 +
1.36 +class PrefCallback : public PLDHashEntryHdr {
1.37 + friend class mozilla::PreferenceServiceReporter;
1.38 +
1.39 + public:
1.40 + typedef PrefCallback* KeyType;
1.41 + typedef const PrefCallback* KeyTypePointer;
1.42 +
1.43 + static const PrefCallback* KeyToPointer(PrefCallback *aKey)
1.44 + {
1.45 + return aKey;
1.46 + }
1.47 +
1.48 + static PLDHashNumber HashKey(const PrefCallback *aKey)
1.49 + {
1.50 + uint32_t hash = mozilla::HashString(aKey->mDomain);
1.51 + return mozilla::AddToHash(hash, aKey->mCanonical);
1.52 + }
1.53 +
1.54 +
1.55 + public:
1.56 + // Create a PrefCallback with a strong reference to its observer.
1.57 + PrefCallback(const char *aDomain, nsIObserver *aObserver,
1.58 + nsPrefBranch *aBranch)
1.59 + : mDomain(aDomain),
1.60 + mBranch(aBranch),
1.61 + mWeakRef(nullptr),
1.62 + mStrongRef(aObserver)
1.63 + {
1.64 + MOZ_COUNT_CTOR(PrefCallback);
1.65 + nsCOMPtr<nsISupports> canonical = do_QueryInterface(aObserver);
1.66 + mCanonical = canonical;
1.67 + }
1.68 +
1.69 + // Create a PrefCallback with a weak reference to its observer.
1.70 + PrefCallback(const char *aDomain,
1.71 + nsISupportsWeakReference *aObserver,
1.72 + nsPrefBranch *aBranch)
1.73 + : mDomain(aDomain),
1.74 + mBranch(aBranch),
1.75 + mWeakRef(do_GetWeakReference(aObserver)),
1.76 + mStrongRef(nullptr)
1.77 + {
1.78 + MOZ_COUNT_CTOR(PrefCallback);
1.79 + nsCOMPtr<nsISupports> canonical = do_QueryInterface(aObserver);
1.80 + mCanonical = canonical;
1.81 + }
1.82 +
1.83 + // Copy constructor needs to be explicit or the linker complains.
1.84 + PrefCallback(const PrefCallback *&aCopy)
1.85 + : mDomain(aCopy->mDomain),
1.86 + mBranch(aCopy->mBranch),
1.87 + mWeakRef(aCopy->mWeakRef),
1.88 + mStrongRef(aCopy->mStrongRef),
1.89 + mCanonical(aCopy->mCanonical)
1.90 + {
1.91 + MOZ_COUNT_CTOR(PrefCallback);
1.92 + }
1.93 +
1.94 + ~PrefCallback()
1.95 + {
1.96 + MOZ_COUNT_DTOR(PrefCallback);
1.97 + }
1.98 +
1.99 + bool KeyEquals(const PrefCallback *aKey) const
1.100 + {
1.101 + // We want to be able to look up a weakly-referencing PrefCallback after
1.102 + // its observer has died so we can remove it from the table. Once the
1.103 + // callback's observer dies, its canonical pointer is stale -- in
1.104 + // particular, we may have allocated a new observer in the same spot in
1.105 + // memory! So we can't just compare canonical pointers to determine
1.106 + // whether aKey refers to the same observer as this.
1.107 + //
1.108 + // Our workaround is based on the way we use this hashtable: When we ask
1.109 + // the hashtable to remove a PrefCallback whose weak reference has
1.110 + // expired, we use as the key for removal the same object as was inserted
1.111 + // into the hashtable. Thus we can say that if one of the keys' weak
1.112 + // references has expired, the two keys are equal iff they're the same
1.113 + // object.
1.114 +
1.115 + if (IsExpired() || aKey->IsExpired())
1.116 + return this == aKey;
1.117 +
1.118 + if (mCanonical != aKey->mCanonical)
1.119 + return false;
1.120 +
1.121 + return mDomain.Equals(aKey->mDomain);
1.122 + }
1.123 +
1.124 + PrefCallback *GetKey() const
1.125 + {
1.126 + return const_cast<PrefCallback*>(this);
1.127 + }
1.128 +
1.129 + // Get a reference to the callback's observer, or null if the observer was
1.130 + // weakly referenced and has been destroyed.
1.131 + already_AddRefed<nsIObserver> GetObserver() const
1.132 + {
1.133 + if (!IsWeak()) {
1.134 + nsCOMPtr<nsIObserver> copy = mStrongRef;
1.135 + return copy.forget();
1.136 + }
1.137 +
1.138 + nsCOMPtr<nsIObserver> observer = do_QueryReferent(mWeakRef);
1.139 + return observer.forget();
1.140 + }
1.141 +
1.142 + const nsCString& GetDomain() const
1.143 + {
1.144 + return mDomain;
1.145 + }
1.146 +
1.147 + nsPrefBranch* GetPrefBranch() const
1.148 + {
1.149 + return mBranch;
1.150 + }
1.151 +
1.152 + // Has this callback's weak reference died?
1.153 + bool IsExpired() const
1.154 + {
1.155 + if (!IsWeak())
1.156 + return false;
1.157 +
1.158 + nsCOMPtr<nsIObserver> observer(do_QueryReferent(mWeakRef));
1.159 + return !observer;
1.160 + }
1.161 +
1.162 + enum { ALLOW_MEMMOVE = true };
1.163 +
1.164 + private:
1.165 + nsCString mDomain;
1.166 + nsPrefBranch *mBranch;
1.167 +
1.168 + // Exactly one of mWeakRef and mStrongRef should be non-null.
1.169 + nsWeakPtr mWeakRef;
1.170 + nsCOMPtr<nsIObserver> mStrongRef;
1.171 +
1.172 + // We need a canonical nsISupports pointer, per bug 578392.
1.173 + nsISupports *mCanonical;
1.174 +
1.175 + bool IsWeak() const
1.176 + {
1.177 + return !!mWeakRef;
1.178 + }
1.179 +};
1.180 +
1.181 +class nsPrefBranch : public nsIPrefBranchInternal,
1.182 + public nsIObserver,
1.183 + public nsSupportsWeakReference
1.184 +{
1.185 + friend class mozilla::PreferenceServiceReporter;
1.186 +public:
1.187 + NS_DECL_ISUPPORTS
1.188 + NS_DECL_NSIPREFBRANCH
1.189 + NS_DECL_NSIPREFBRANCH2
1.190 + NS_DECL_NSIOBSERVER
1.191 +
1.192 + nsPrefBranch(const char *aPrefRoot, bool aDefaultBranch);
1.193 + virtual ~nsPrefBranch();
1.194 +
1.195 + int32_t GetRootLength() { return mPrefRootLength; }
1.196 +
1.197 + nsresult RemoveObserverFromMap(const char *aDomain, nsISupports *aObserver);
1.198 +
1.199 + static void NotifyObserver(const char *newpref, void *data);
1.200 +
1.201 + size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf);
1.202 +
1.203 +protected:
1.204 + nsPrefBranch() /* disallow use of this constructer */
1.205 + { }
1.206 +
1.207 + nsresult GetDefaultFromPropertiesFile(const char *aPrefName, char16_t **return_buf);
1.208 + // As SetCharPref, but without any check on the length of |aValue|
1.209 + nsresult SetCharPrefInternal(const char *aPrefName, const char *aValue);
1.210 + // Reject strings that are more than 1Mb, warn if strings are more than 16kb
1.211 + nsresult CheckSanityOfStringLength(const char* aPrefName, const nsAString& aValue);
1.212 + nsresult CheckSanityOfStringLength(const char* aPrefName, const char* aValue);
1.213 + nsresult CheckSanityOfStringLength(const char* aPrefName, const uint32_t aLength);
1.214 + void RemoveExpiredCallback(PrefCallback *aCallback);
1.215 + const char *getPrefName(const char *aPrefName);
1.216 + void freeObserverList(void);
1.217 +
1.218 + friend PLDHashOperator
1.219 + FreeObserverFunc(PrefCallback *aKey,
1.220 + nsAutoPtr<PrefCallback> &aCallback,
1.221 + void *aArgs);
1.222 +
1.223 +private:
1.224 + int32_t mPrefRootLength;
1.225 + nsCString mPrefRoot;
1.226 + bool mIsDefault;
1.227 +
1.228 + bool mFreeingObserverList;
1.229 + nsClassHashtable<PrefCallback, PrefCallback> mObservers;
1.230 +};
1.231 +
1.232 +
1.233 +class nsPrefLocalizedString : public nsIPrefLocalizedString,
1.234 + public nsISupportsString
1.235 +{
1.236 +public:
1.237 + nsPrefLocalizedString();
1.238 + virtual ~nsPrefLocalizedString();
1.239 +
1.240 + NS_DECL_ISUPPORTS
1.241 + NS_FORWARD_NSISUPPORTSSTRING(mUnicodeString->)
1.242 + NS_FORWARD_NSISUPPORTSPRIMITIVE(mUnicodeString->)
1.243 +
1.244 + nsresult Init();
1.245 +
1.246 +private:
1.247 + NS_IMETHOD GetData(char16_t**);
1.248 + NS_IMETHOD SetData(const char16_t* aData);
1.249 + NS_IMETHOD SetDataWithLength(uint32_t aLength, const char16_t *aData);
1.250 +
1.251 + nsCOMPtr<nsISupportsString> mUnicodeString;
1.252 +};
1.253 +
1.254 +
1.255 +class nsRelativeFilePref : public nsIRelativeFilePref
1.256 +{
1.257 +public:
1.258 + NS_DECL_ISUPPORTS
1.259 + NS_DECL_NSIRELATIVEFILEPREF
1.260 +
1.261 + nsRelativeFilePref();
1.262 + virtual ~nsRelativeFilePref();
1.263 +
1.264 +private:
1.265 + nsCOMPtr<nsIFile> mFile;
1.266 + nsCString mRelativeToKey;
1.267 +};
1.268 +
1.269 +#endif
