The Tor Browser: dom/xslt/xpath/txXPCOMExtensionFunction.cpp@97036ab72558 (annotated)

dom/xslt/xpath/txXPCOMExtensionFunction.cpp@97036ab72558 (annotated)

dom/xslt/xpath/txXPCOMExtensionFunction.cpp

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- 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 "nsAutoPtr.h"
 #include "nsComponentManagerUtils.h"
 #include "nsDependentString.h"
 #include "nsIAtom.h"
 #include "nsIInterfaceInfoManager.h"
 #include "nsServiceManagerUtils.h"
 #include "txExpr.h"
 #include "txIFunctionEvaluationContext.h"
 #include "txIXPathContext.h"
 #include "txNodeSetAdaptor.h"
 #include "txXPathTreeWalker.h"
 #include "xptcall.h"
 #include "txXPathObjectAdaptor.h"
 #include "mozilla/Attributes.h"
 #include "nsIClassInfo.h"
 #include "nsIInterfaceInfo.h"
 NS_IMPL_ISUPPORTS(txXPathObjectAdaptor, txIXPathObject)
 class txFunctionEvaluationContext MOZ_FINAL : public txIFunctionEvaluationContext
 {
 public:
     txFunctionEvaluationContext(txIEvalContext *aContext, nsISupports *aState);
     NS_DECL_ISUPPORTS
     NS_DECL_TXIFUNCTIONEVALUATIONCONTEXT
     void ClearContext()
     {
         mContext = nullptr;
     }
 private:
     txIEvalContext *mContext;
     nsCOMPtr<nsISupports> mState;
 };
 txFunctionEvaluationContext::txFunctionEvaluationContext(txIEvalContext *aContext,
                                                          nsISupports *aState)
     : mContext(aContext),
       mState(aState)
 {
 }
 NS_IMPL_ISUPPORTS(txFunctionEvaluationContext, txIFunctionEvaluationContext)
 NS_IMETHODIMP
 txFunctionEvaluationContext::GetPosition(uint32_t *aPosition)
 {
     NS_ENSURE_TRUE(mContext, NS_ERROR_FAILURE);
     *aPosition = mContext->position();
     return NS_OK;
 }
 NS_IMETHODIMP
 txFunctionEvaluationContext::GetSize(uint32_t *aSize)
 {
     NS_ENSURE_TRUE(mContext, NS_ERROR_FAILURE);
     *aSize = mContext->size();
     return NS_OK;
 }
 NS_IMETHODIMP
 txFunctionEvaluationContext::GetContextNode(nsIDOMNode **aNode)
 {
     NS_ENSURE_TRUE(mContext, NS_ERROR_FAILURE);
     return txXPathNativeNode::getNode(mContext->getContextNode(), aNode);
 }
 NS_IMETHODIMP
 txFunctionEvaluationContext::GetState(nsISupports **aState)
 {
     NS_IF_ADDREF(*aState = mState);
     return NS_OK;
 }
 enum txArgumentType {
     eBOOLEAN = nsXPTType::T_BOOL,
     eNUMBER = nsXPTType::T_DOUBLE,
     eSTRING = nsXPTType::T_DOMSTRING,
     eNODESET,
     eCONTEXT,
     eOBJECT,
     eUNKNOWN
 };
 class txXPCOMExtensionFunctionCall : public FunctionCall
 {
 public:
     txXPCOMExtensionFunctionCall(nsISupports *aHelper, const nsIID &aIID,
                                  uint16_t aMethodIndex,
 #ifdef TX_TO_STRING
                                  nsIAtom *aName,
 #endif
                                  nsISupports *aState);
     TX_DECL_FUNCTION
 private:
     txArgumentType GetParamType(const nsXPTParamInfo &aParam,
                                 nsIInterfaceInfo *aInfo);
     nsCOMPtr<nsISupports> mHelper;
     nsIID mIID;
     uint16_t mMethodIndex;
 #ifdef TX_TO_STRING
     nsCOMPtr<nsIAtom> mName;
 #endif
     nsCOMPtr<nsISupports> mState;
 };
 txXPCOMExtensionFunctionCall::txXPCOMExtensionFunctionCall(nsISupports *aHelper,
                                                            const nsIID &aIID,
                                                            uint16_t aMethodIndex,
 #ifdef TX_TO_STRING
                                                            nsIAtom *aName,
 #endif
                                                            nsISupports *aState)
     : mHelper(aHelper),
       mIID(aIID),
       mMethodIndex(aMethodIndex),
 #ifdef TX_TO_STRING
       mName(aName),
 #endif
       mState(aState)
 {
 }
 class txInterfacesArrayHolder
 {
 public:
     txInterfacesArrayHolder(nsIID **aArray, uint32_t aCount) : mArray(aArray),
                                                                mCount(aCount)
     {
     }
     ~txInterfacesArrayHolder()
     {
         NS_FREE_XPCOM_ALLOCATED_POINTER_ARRAY(mCount, mArray);
     }
 private:
     nsIID **mArray;
     uint32_t mCount;
 };
 static nsresult
 LookupFunction(const char *aContractID, nsIAtom* aName, nsIID &aIID,
                uint16_t &aMethodIndex, nsISupports **aHelper)
 {
     nsresult rv;
     nsCOMPtr<nsISupports> helper = do_GetService(aContractID, &rv);
     NS_ENSURE_SUCCESS(rv, rv);
     nsCOMPtr<nsIClassInfo> classInfo = do_QueryInterface(helper, &rv);
     NS_ENSURE_SUCCESS(rv, rv);
     nsCOMPtr<nsIInterfaceInfoManager> iim =
         do_GetService(NS_INTERFACEINFOMANAGER_SERVICE_CONTRACTID);
     NS_ENSURE_TRUE(iim, NS_ERROR_FAILURE);
     nsIID** iidArray = nullptr;
     uint32_t iidCount = 0;
     rv = classInfo->GetInterfaces(&iidCount, &iidArray);
     NS_ENSURE_SUCCESS(rv, rv);
     txInterfacesArrayHolder holder(iidArray, iidCount);
     // Remove any minus signs and uppercase the following letter (so
     // foo-bar becomes fooBar). Note that if there are any names that already
     // have uppercase letters they might cause false matches (both fooBar and
     // foo-bar matching fooBar).
     const char16_t *name = aName->GetUTF16String();
     nsAutoCString methodName;
     char16_t letter;
     bool upperNext = false;
     while ((letter = *name)) {
         if (letter == '-') {
             upperNext = true;
         }
         else {
             MOZ_ASSERT(nsCRT::IsAscii(letter),
                        "invalid static_cast coming up");
             methodName.Append(upperNext ?
                               nsCRT::ToUpper(static_cast<char>(letter)) :
                               letter);
             upperNext = false;
         }
         ++name;
     }
     uint32_t i;
     for (i = 0; i < iidCount; ++i) {
         nsIID *iid = iidArray[i];
         nsCOMPtr<nsIInterfaceInfo> info;
         rv = iim->GetInfoForIID(iid, getter_AddRefs(info));
         NS_ENSURE_SUCCESS(rv, rv);
         uint16_t methodIndex;
         const nsXPTMethodInfo *methodInfo;
         rv = info->GetMethodInfoForName(methodName.get(), &methodIndex,
                                         &methodInfo);
         if (NS_SUCCEEDED(rv)) {
             // Exclude notxpcom and hidden. Also check that we have at least a
             // return value (the xpidl compiler ensures that that return value
             // is the last argument).
             uint8_t paramCount = methodInfo->GetParamCount();
             if (methodInfo->IsNotXPCOM() || methodInfo->IsHidden() ||
                 paramCount == 0 ||
                 !methodInfo->GetParam(paramCount - 1).IsRetval()) {
                 return NS_ERROR_FAILURE;
             }
             aIID = *iid;
             aMethodIndex = methodIndex;
             return helper->QueryInterface(aIID, (void**)aHelper);
         }
     }
     return NS_ERROR_XPATH_UNKNOWN_FUNCTION;
 }
 /* static */
 nsresult
 TX_ResolveFunctionCallXPCOM(const nsCString &aContractID, int32_t aNamespaceID,
                             nsIAtom* aName, nsISupports *aState,
                             FunctionCall **aFunction)
 {
     nsIID iid;
     uint16_t methodIndex = 0;
     nsCOMPtr<nsISupports> helper;
     nsresult rv = LookupFunction(aContractID.get(), aName, iid, methodIndex,
                                  getter_AddRefs(helper));
     NS_ENSURE_SUCCESS(rv, rv);
     if (!aFunction) {
         return NS_OK;
     }
     *aFunction = new txXPCOMExtensionFunctionCall(helper, iid, methodIndex,
 #ifdef TX_TO_STRING
                                                   aName,
 #endif
                                                   aState);
     return *aFunction ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
 }
 txArgumentType
 txXPCOMExtensionFunctionCall::GetParamType(const nsXPTParamInfo &aParam,
                                            nsIInterfaceInfo *aInfo)
 {
     uint8_t tag = aParam.GetType().TagPart();
     switch (tag) {
         case nsXPTType::T_BOOL:
         case nsXPTType::T_DOUBLE:
         case nsXPTType::T_DOMSTRING:
         {
             return txArgumentType(tag);
         }
         case nsXPTType::T_INTERFACE:
         case nsXPTType::T_INTERFACE_IS:
         {
             nsIID iid;
             aInfo->GetIIDForParamNoAlloc(mMethodIndex, &aParam, &iid);
             if (iid.Equals(NS_GET_IID(txINodeSet))) {
                 return eNODESET;
             }
             if (iid.Equals(NS_GET_IID(txIFunctionEvaluationContext))) {
                 return eCONTEXT;
             }
             if (iid.Equals(NS_GET_IID(txIXPathObject))) {
                 return eOBJECT;
             }
         }
         // FALLTHROUGH
         default:
         {
             // XXX Error!
             return eUNKNOWN;
         }
     }
 }
 class txParamArrayHolder
 {
 public:
     txParamArrayHolder()
         : mCount(0)
     {
     }
     ~txParamArrayHolder();
     bool Init(uint8_t aCount);
     operator nsXPTCVariant*() const
     {
       return mArray;
     }
 private:
     nsAutoArrayPtr<nsXPTCVariant> mArray;
     uint8_t mCount;
 };
 txParamArrayHolder::~txParamArrayHolder()
 {
     uint8_t i;
     for (i = 0; i < mCount; ++i) {
         nsXPTCVariant &variant = mArray[i];
         if (variant.DoesValNeedCleanup()) {
             if (variant.type.TagPart() == nsXPTType::T_DOMSTRING)
                 delete (nsAString*)variant.val.p;
             else {
                 NS_ABORT_IF_FALSE(variant.type.TagPart() == nsXPTType::T_INTERFACE ||
                                   variant.type.TagPart() == nsXPTType::T_INTERFACE_IS,
                                   "We only support cleanup of strings and interfaces "
                                   "here, and this looks like neither!");
                 static_cast<nsISupports*>(variant.val.p)->Release();
             }
         }
     }
 }
 bool
 txParamArrayHolder::Init(uint8_t aCount)
 {
     mCount = aCount;
     mArray = new nsXPTCVariant[mCount];
     if (!mArray) {
         return false;
     }
     memset(mArray, 0, mCount * sizeof(nsXPTCVariant));
     return true;
 }
 nsresult
 txXPCOMExtensionFunctionCall::evaluate(txIEvalContext* aContext,
                                        txAExprResult** aResult)
 {
     nsCOMPtr<nsIInterfaceInfoManager> iim =
         do_GetService(NS_INTERFACEINFOMANAGER_SERVICE_CONTRACTID);
     NS_ENSURE_TRUE(iim, NS_ERROR_FAILURE);
     nsCOMPtr<nsIInterfaceInfo> info;
     nsresult rv = iim->GetInfoForIID(&mIID, getter_AddRefs(info));
     NS_ENSURE_SUCCESS(rv, rv);
     const nsXPTMethodInfo *methodInfo;
     rv = info->GetMethodInfo(mMethodIndex, &methodInfo);
     NS_ENSURE_SUCCESS(rv, rv);
     uint8_t paramCount = methodInfo->GetParamCount();
     uint8_t inArgs = paramCount - 1;
     txParamArrayHolder invokeParams;
     if (!invokeParams.Init(paramCount)) {
         return NS_ERROR_OUT_OF_MEMORY;
     }
     const nsXPTParamInfo &paramInfo = methodInfo->GetParam(0);
     txArgumentType type = GetParamType(paramInfo, info);
     if (type == eUNKNOWN) {
         return NS_ERROR_FAILURE;
     }
     txFunctionEvaluationContext *context;
     uint32_t paramStart = 0;
     if (type == eCONTEXT) {
         if (paramInfo.IsOut()) {
             // We don't support out values.
             return NS_ERROR_FAILURE;
         }
         // Create context wrapper.
         context = new txFunctionEvaluationContext(aContext, mState);
         if (!context) {
             return NS_ERROR_OUT_OF_MEMORY;
         }
         nsXPTCVariant &invokeParam = invokeParams[0];
         invokeParam.type = paramInfo.GetType();
         invokeParam.SetValNeedsCleanup();
         NS_ADDREF((txIFunctionEvaluationContext*&)invokeParam.val.p = context);
         // Skip first argument, since it's the context.
         paramStart = 1;
     }
     else {
         context = nullptr;
     }
     // XXX varargs
     if (!requireParams(inArgs - paramStart, inArgs - paramStart, aContext)) {
         return NS_ERROR_FAILURE;
     }
     uint32_t i;
     for (i = paramStart; i < inArgs; ++i) {
         Expr* expr = mParams[i - paramStart];
         const nsXPTParamInfo &paramInfo = methodInfo->GetParam(i);
         txArgumentType type = GetParamType(paramInfo, info);
         if (type == eUNKNOWN) {
             return NS_ERROR_FAILURE;
         }
         nsXPTCVariant &invokeParam = invokeParams[i];
         if (paramInfo.IsOut()) {
             // We don't support out values.
             return NS_ERROR_FAILURE;
         }
         invokeParam.type = paramInfo.GetType();
         switch (type) {
             case eNODESET:
             {
                 nsRefPtr<txNodeSet> nodes;
                 rv = evaluateToNodeSet(expr, aContext, getter_AddRefs(nodes));
                 NS_ENSURE_SUCCESS(rv, rv);
                 txNodeSetAdaptor *adaptor = new txNodeSetAdaptor(nodes);
                 if (!adaptor) {
                     return NS_ERROR_OUT_OF_MEMORY;
                 }
                 nsCOMPtr<txINodeSet> nodeSet = adaptor;
                 rv = adaptor->Init();
                 NS_ENSURE_SUCCESS(rv, rv);
                 invokeParam.SetValNeedsCleanup();
                 nodeSet.swap((txINodeSet*&)invokeParam.val.p);
                 break;
             }
             case eBOOLEAN:
             {
                 rv = expr->evaluateToBool(aContext, invokeParam.val.b);
                 NS_ENSURE_SUCCESS(rv, rv);
                 break;
             }
             case eNUMBER:
             {
                 double dbl;
                 rv = evaluateToNumber(mParams[0], aContext, &dbl);
                 NS_ENSURE_SUCCESS(rv, rv);
                 invokeParam.val.d = dbl;
                 break;
             }
             case eSTRING:
             {
                 nsString *value = new nsString();
                 if (!value) {
                     return NS_ERROR_OUT_OF_MEMORY;
                 }
                 rv = expr->evaluateToString(aContext, *value);
                 NS_ENSURE_SUCCESS(rv, rv);
                 invokeParam.SetValNeedsCleanup();
                 invokeParam.val.p = value;
                 break;
             }
             case eOBJECT:
             {
               nsRefPtr<txAExprResult> exprRes;
               rv = expr->evaluate(aContext, getter_AddRefs(exprRes));
               NS_ENSURE_SUCCESS(rv, rv);
               nsCOMPtr<txIXPathObject> adaptor =
                 new txXPathObjectAdaptor(exprRes);
               if (!adaptor) {
                   return NS_ERROR_OUT_OF_MEMORY;
               }
               invokeParam.SetValNeedsCleanup();
               adaptor.swap((txIXPathObject*&)invokeParam.val.p);
               break;
             }
             case eCONTEXT:
             case eUNKNOWN:
             {
                 // We only support passing the context as the *first* argument.
                 return NS_ERROR_FAILURE;
             }
         }
     }
     const nsXPTParamInfo &returnInfo = methodInfo->GetParam(inArgs);
     txArgumentType returnType = GetParamType(returnInfo, info);
     if (returnType == eUNKNOWN) {
         return NS_ERROR_FAILURE;
     }
     nsXPTCVariant &returnParam = invokeParams[inArgs];
     returnParam.type = returnInfo.GetType();
     if (returnType == eSTRING) {
         nsString *value = new nsString();
         if (!value) {
             return NS_ERROR_FAILURE;
         }
         returnParam.SetValNeedsCleanup();
         returnParam.val.p = value;
     }
     else {
         returnParam.SetIndirect();
         if (returnType == eNODESET || returnType == eOBJECT) {
             returnParam.SetValNeedsCleanup();
         }
     }
     rv = NS_InvokeByIndex(mHelper, mMethodIndex, paramCount, invokeParams);
     // In case someone is holding on to the txFunctionEvaluationContext which
     // could thus stay alive longer than this function.
     if (context) {
         context->ClearContext();
     }
     NS_ENSURE_SUCCESS(rv, rv);
     switch (returnType) {
         case eNODESET:
         {
             txINodeSet* nodeSet = static_cast<txINodeSet*>(returnParam.val.p);
             nsCOMPtr<txIXPathObject> object = do_QueryInterface(nodeSet, &rv);
             NS_ENSURE_SUCCESS(rv, rv);
             NS_ADDREF(*aResult = object->GetResult());
             return NS_OK;
         }
         case eBOOLEAN:
         {
             aContext->recycler()->getBoolResult(returnParam.val.b, aResult);
             return NS_OK;
         }
         case eNUMBER:
         {
             return aContext->recycler()->getNumberResult(returnParam.val.d,
                                                          aResult);
         }
         case eSTRING:
         {
             nsString *returned = static_cast<nsString*>
                                             (returnParam.val.p);
             return aContext->recycler()->getStringResult(*returned, aResult);
         }
         case eOBJECT:
         {
             txIXPathObject *object =
                  static_cast<txIXPathObject*>(returnParam.val.p);
             NS_ADDREF(*aResult = object->GetResult());
             return NS_OK;
         }
         default:
         {
             // Huh?
             return NS_ERROR_FAILURE;
         }
     }
 }
 Expr::ResultType
 txXPCOMExtensionFunctionCall::getReturnType()
 {
     // It doesn't really matter what we return here, but it might
     // be a good idea to try to keep this as unoptimizable as possible
     return ANY_RESULT;
 }
 bool
 txXPCOMExtensionFunctionCall::isSensitiveTo(ContextSensitivity aContext)
 {
     // It doesn't really matter what we return here, but it might
     // be a good idea to try to keep this as unoptimizable as possible
     return true;
 }
 #ifdef TX_TO_STRING
 nsresult
 txXPCOMExtensionFunctionCall::getNameAtom(nsIAtom** aAtom)
 {
     NS_ADDREF(*aAtom = mName);
     return NS_OK;
 }
 #endif

The Tor Browser / annotate

dom/xslt/xpath/txXPCOMExtensionFunction.cpp@97036ab72558 (annotated)

dom/xslt/xpath/txXPCOMExtensionFunction.cpp