The Tor Browser: comparison rdf/base/src/nsContainerEnumerator.cpp

--1:000000000000
+:f231c94f7679
+/* -*- 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/. */
+/*
+A simple cursor that enumerates the elements of an RDF container
+(RDF:Bag, RDF:Seq, or RDF:Alt).
+Caveats
+-------
+1. This uses an implementation-specific detail to determine the
+index of the last element in the container; specifically, the RDF
+utilities maintain a counter attribute on the container that
+holds the numeric value of the next value that is to be
+assigned. So, this cursor will bust if you use it with a bag that
+hasn't been created using the RDF utility routines.
+*/
+#include "nscore.h"
+#include "nsCOMPtr.h"
+#include "nsIRDFContainerUtils.h"
+#include "nsIRDFDataSource.h"
+#include "nsIRDFNode.h"
+#include "nsIRDFService.h"
+#include "nsIServiceManager.h"
+#include "nsRDFCID.h"
+#include "nsString.h"
+#include "nsXPIDLString.h"
+#include "prlog.h"
+#include "rdf.h"
+#include "rdfutil.h"
+////////////////////////////////////////////////////////////////////////
+class ContainerEnumeratorImpl : public nsISimpleEnumerator {
+private:
+// pseudo-constants
+static nsrefcnt              gRefCnt;
+static nsIRDFResource*       kRDF_nextVal;
+static nsIRDFContainerUtils* gRDFC;
+nsCOMPtr<nsIRDFDataSource>      mDataSource;
+nsCOMPtr<nsIRDFResource>        mContainer;
+nsCOMPtr<nsIRDFResource>        mOrdinalProperty;
+nsCOMPtr<nsISimpleEnumerator>   mCurrent;
+nsCOMPtr<nsIRDFNode>            mResult;
+int32_t mNextIndex;
+public:
+ContainerEnumeratorImpl(nsIRDFDataSource* ds, nsIRDFResource* container);
+virtual ~ContainerEnumeratorImpl();
+nsresult Init();
+NS_DECL_ISUPPORTS
+NS_DECL_NSISIMPLEENUMERATOR
+};
+nsrefcnt              ContainerEnumeratorImpl::gRefCnt;
+nsIRDFResource*       ContainerEnumeratorImpl::kRDF_nextVal;
+nsIRDFContainerUtils* ContainerEnumeratorImpl::gRDFC;
+ContainerEnumeratorImpl::ContainerEnumeratorImpl(nsIRDFDataSource* aDataSource,
+nsIRDFResource* aContainer)
+: mDataSource(aDataSource),
+mContainer(aContainer),
+mNextIndex(1)
+{
+}
+nsresult
+ContainerEnumeratorImpl::Init()
+{
+if (gRefCnt++ == 0) {
+nsresult rv;
+NS_DEFINE_CID(kRDFServiceCID, NS_RDFSERVICE_CID);
+nsCOMPtr<nsIRDFService> rdf = do_GetService(kRDFServiceCID);
+NS_ASSERTION(rdf != nullptr, "unable to acquire resource manager");
+if (! rdf)
+return NS_ERROR_FAILURE;
+rv = rdf->GetResource(NS_LITERAL_CSTRING(RDF_NAMESPACE_URI "nextVal"), &kRDF_nextVal);
+NS_ASSERTION(NS_SUCCEEDED(rv), "unable to get resource");
+if (NS_FAILED(rv)) return rv;
+NS_DEFINE_CID(kRDFContainerUtilsCID, NS_RDFCONTAINERUTILS_CID);
+rv = CallGetService(kRDFContainerUtilsCID, &gRDFC);
+if (NS_FAILED(rv)) return rv;
+}
+return NS_OK;
+}
+ContainerEnumeratorImpl::~ContainerEnumeratorImpl()
+{
+if (--gRefCnt == 0) {
+NS_IF_RELEASE(kRDF_nextVal);
+NS_IF_RELEASE(gRDFC);
+}
+}
+NS_IMPL_ISUPPORTS(ContainerEnumeratorImpl, nsISimpleEnumerator)
+NS_IMETHODIMP
+ContainerEnumeratorImpl::HasMoreElements(bool* aResult)
+{
+NS_PRECONDITION(aResult != nullptr, "null ptr");
+if (! aResult)
+return NS_ERROR_NULL_POINTER;
+nsresult rv;
+// If we've already queued up a next value, then we know there are more elements.
+if (mResult) {
+*aResult = true;
+return NS_OK;
+}
+// Otherwise, we need to grovel
+// Figure out the upper bound so we'll know when we're done. Since it's
+// possible that we're targeting a composite datasource, we'll need to
+// "GetTargets()" and take the maximum value of "nextVal" to know the
+// upper bound.
+//
+// Remember that since nextVal is the next index that we'd assign
+// to an element in a container, it's *one more* than count of
+// elements in the container.
+int32_t max = 0;
+nsCOMPtr<nsISimpleEnumerator> targets;
+rv = mDataSource->GetTargets(mContainer, kRDF_nextVal, true, getter_AddRefs(targets));
+if (NS_FAILED(rv)) return rv;
+while (1) {
+bool hasmore;
+targets->HasMoreElements(&hasmore);
+if (! hasmore)
+break;
+nsCOMPtr<nsISupports> isupports;
+targets->GetNext(getter_AddRefs(isupports));
+nsCOMPtr<nsIRDFLiteral> nextValLiteral = do_QueryInterface(isupports);
+if (! nextValLiteral)
+continue;
+const char16_t *nextValStr;
+nextValLiteral->GetValueConst(&nextValStr);
+nsresult err;
+int32_t nextVal = nsAutoString(nextValStr).ToInteger(&err);
+if (nextVal > max)
+max = nextVal;
+}
+// Now pre-fetch our next value into mResult.
+while (mCurrent || mNextIndex < max) {
+// If mCurrent has been depleted, then conjure up a new one
+if (! mCurrent) {
+rv = gRDFC->IndexToOrdinalResource(mNextIndex, getter_AddRefs(mOrdinalProperty));
+if (NS_FAILED(rv)) return rv;
+rv = mDataSource->GetTargets(mContainer, mOrdinalProperty, true, getter_AddRefs(mCurrent));
+if (NS_FAILED(rv)) return rv;
+++mNextIndex;
+}
+if (mCurrent) {
+bool hasMore;
+rv = mCurrent->HasMoreElements(&hasMore);
+if (NS_FAILED(rv)) return rv;
+// Is the current enumerator depleted? If so, iterate to
+// the next index.
+if (! hasMore) {
+mCurrent = nullptr;
+continue;
+}
+// "Peek" ahead and pull out the next target.
+nsCOMPtr<nsISupports> result;
+rv = mCurrent->GetNext(getter_AddRefs(result));
+if (NS_FAILED(rv)) return rv;
+mResult = do_QueryInterface(result, &rv);
+if (NS_FAILED(rv)) return rv;
+*aResult = true;
+return NS_OK;
+}
+}
+// If we get here, we ran out of elements. The cursor is empty.
+*aResult = false;
+return NS_OK;
+}
+NS_IMETHODIMP
+ContainerEnumeratorImpl::GetNext(nsISupports** aResult)
+{
+nsresult rv;
+bool hasMore;
+rv = HasMoreElements(&hasMore);
+if (NS_FAILED(rv)) return rv;
+if (! hasMore)
+return NS_ERROR_UNEXPECTED;
+NS_ADDREF(*aResult = mResult);
+mResult = nullptr;
+return NS_OK;
+}
+////////////////////////////////////////////////////////////////////////
+nsresult
+NS_NewContainerEnumerator(nsIRDFDataSource* aDataSource,
+nsIRDFResource* aContainer,
+nsISimpleEnumerator** aResult)
+{
+NS_PRECONDITION(aDataSource != nullptr, "null ptr");
+if (! aDataSource)
+return NS_ERROR_NULL_POINTER;
+NS_PRECONDITION(aContainer != nullptr, "null ptr");
+if (! aContainer)
+return NS_ERROR_NULL_POINTER;
+NS_PRECONDITION(aResult != nullptr, "null ptr");
+if (! aResult)
+return NS_ERROR_NULL_POINTER;
+ContainerEnumeratorImpl* result = new ContainerEnumeratorImpl(aDataSource, aContainer);
+if (! result)
+return NS_ERROR_OUT_OF_MEMORY;
+NS_ADDREF(result);
+nsresult rv = result->Init();
+if (NS_FAILED(rv))
+NS_RELEASE(result);
+*aResult = result;
+return rv;
+}

The Tor Browser / file comparison

comparison: rdf/base/src/nsContainerEnumerator.cpp

rdf/base/src/nsContainerEnumerator.cpp