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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /rdf/base/nsContainerEnumerator.cpp
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
Diffstat (limited to 'rdf/base/nsContainerEnumerator.cpp')
-rw-r--r--rdf/base/nsContainerEnumerator.cpp263
1 files changed, 263 insertions, 0 deletions
diff --git a/rdf/base/nsContainerEnumerator.cpp b/rdf/base/nsContainerEnumerator.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/. */
+
+/*
+
+ 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 "mozilla/Logging.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;
+
+ virtual ~ContainerEnumeratorImpl();
+
+public:
+ ContainerEnumeratorImpl(nsIRDFDataSource* ds, nsIRDFResource* container);
+
+ 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;
+}