rdf/base/rdfTriplesSerializer.cpp

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "nsIOutputStream.h"
   7 #include "nsReadableUtils.h"
   8 #include "nsCRT.h"
   9 #include "nsCOMPtr.h"
  10 #include "nsString.h"
  11 #include "nsPrintfCString.h"
  12 #include "nsIBufferedStreams.h"
  13 #include "nsNetCID.h"
  14 #include "nsComponentManagerUtils.h"
  15
  16 #include "rdfISerializer.h"
  17 #include "rdfIDataSource.h"
  18 #include "rdfITripleVisitor.h"
  19
  20 #include "nsIRDFResource.h"
  21 #include "nsIRDFLiteral.h"
  22 #include "mozilla/Attributes.h"
  23
  24 class TriplesVisitor MOZ_FINAL : public rdfITripleVisitor
  25 {
  26 public:
  27     TriplesVisitor(nsIOutputStream* aOut) : mOut(aOut) {}
  28     NS_DECL_RDFITRIPLEVISITOR
  29     NS_DECL_ISUPPORTS
  30 protected:
  31     ~TriplesVisitor() {}
  32     nsresult writeResource(nsIRDFResource* aResource);
  33     nsIOutputStream* mOut;
  34 };
  35
  36 NS_IMPL_ISUPPORTS(TriplesVisitor, rdfITripleVisitor)
  37
  38 nsresult
  39 TriplesVisitor::writeResource(nsIRDFResource *aResource)
  40 {
  41     nsCString res;
  42     uint32_t writeCount, wroteCount;
  43     mOut->Write("<", 1, &wroteCount);
  44     NS_ENSURE_TRUE(wroteCount == 1, NS_ERROR_FAILURE);
  45     nsresult rv = aResource->GetValueUTF8(res);
  46     NS_ENSURE_SUCCESS(rv, rv);
  47     writeCount = res.Length();
  48     mOut->Write(res.get(), writeCount, &wroteCount);
  49     NS_ENSURE_TRUE(writeCount == wroteCount, NS_ERROR_FAILURE);
  50     mOut->Write("> ", 2, &wroteCount);
  51     NS_ENSURE_TRUE(wroteCount == 2, NS_ERROR_FAILURE);
  52     return NS_OK;
  53 }
  54
  55 NS_IMETHODIMP
  56 TriplesVisitor::Visit(nsIRDFNode *aSubject, nsIRDFResource *aPredicate,
  57                       nsIRDFNode *aObject, bool aTruthValue)
  58 {
  59     nsCOMPtr<nsIRDFResource> subjectRes = do_QueryInterface(aSubject);
  60     nsresult rv = NS_OK;
  61     if (subjectRes) {
  62         rv = writeResource(subjectRes);
  63     }
  64     if (NS_FAILED(rv)) {
  65         return rv;
  66     }
  67     rv = writeResource(aPredicate);
  68     if (NS_FAILED(rv)) {
  69         return rv;
  70     }
  71     nsCOMPtr<nsIRDFResource> res = do_QueryInterface(aObject);
  72     nsCOMPtr<nsIRDFLiteral> lit;
  73     nsCOMPtr<nsIRDFInt> intLit;
  74     uint32_t wroteCount;
  75     if (res) {
  76         rv = writeResource(res);
  77     } else if ((lit = do_QueryInterface(aObject)) != nullptr) {
  78         const char16_t *value;
  79         lit->GetValueConst(&value);
  80         nsAutoCString object;
  81         object.Append('"');
  82         AppendUTF16toUTF8(value, object);
  83         object.AppendLiteral("\" ");
  84         uint32_t writeCount = object.Length();
  85         rv = mOut->Write(object.get(), writeCount, &wroteCount);
  86         NS_ENSURE_TRUE(writeCount == wroteCount, NS_ERROR_FAILURE);
  87     } else if ((intLit = do_QueryInterface(aObject)) != nullptr) {
  88         int32_t value;
  89         intLit->GetValue(&value);
  90         nsPrintfCString
  91             object("\"%i\"^^<http://www.w3.org/2001/XMLSchema#integer> ",
  92                    value);
  93         uint32_t writeCount = object.Length();
  94         rv = mOut->Write(object.get(), writeCount, &wroteCount);
  95         NS_ENSURE_TRUE(writeCount == wroteCount, NS_ERROR_FAILURE);
  96     }
  97     NS_ENSURE_SUCCESS(rv, rv);
  98     return mOut->Write(".\n", 2, &wroteCount);
  99 }
 100
 101 class rdfTriplesSerializer MOZ_FINAL : public rdfISerializer
 102 {
 103 public:
 104   NS_DECL_ISUPPORTS
 105   NS_DECL_RDFISERIALIZER
 106
 107   rdfTriplesSerializer();
 108
 109 private:
 110   ~rdfTriplesSerializer();
 111
 112 };
 113
 114 nsresult
 115 NS_NewTriplesSerializer(rdfISerializer** aResult)
 116 {
 117     NS_PRECONDITION(aResult != nullptr, "null ptr");
 118     if (! aResult)
 119         return NS_ERROR_NULL_POINTER;
 120
 121     *aResult = new rdfTriplesSerializer();
 122     if (! *aResult)
 123         return NS_ERROR_OUT_OF_MEMORY;
 124     NS_ADDREF(*aResult);
 125     return NS_OK;
 126 }
 127
 128 NS_IMPL_ISUPPORTS(rdfTriplesSerializer, rdfISerializer)
 129
 130 rdfTriplesSerializer::rdfTriplesSerializer()
 131 {
 132 }
 133
 134 rdfTriplesSerializer::~rdfTriplesSerializer()
 135 {
 136 }
 137
 138 NS_IMETHODIMP
 139 rdfTriplesSerializer::Serialize(rdfIDataSource *aDataSource,
 140                                 nsIOutputStream *aOut)
 141 {
 142     nsresult rv;
 143     nsCOMPtr<nsIBufferedOutputStream> bufout =
 144         do_CreateInstance(NS_BUFFEREDOUTPUTSTREAM_CONTRACTID, &rv);
 145     NS_ENSURE_SUCCESS(rv, rv);
 146     rv = bufout->Init(aOut, 1024);
 147     NS_ENSURE_SUCCESS(rv, rv);
 148     nsCOMPtr<rdfITripleVisitor> tv = new TriplesVisitor(bufout);
 149     NS_ENSURE_TRUE(tv, NS_ERROR_OUT_OF_MEMORY);
 150     return aDataSource->VisitAllTriples(tv);
 151 }