Added error reporting to QJsonParser

Change-Id: Ib2390c0faf1ed7ada3fc185abce83740ad112929
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>

5 files changed, 252 insertions, 23 deletions

diff --git a/src/corelib/json/qjsondocument.cpp b/src/corelib/json/qjsondocument.cpp
index 5ae1bcbe4e..8a7fa760ae 100644
--- a/src/corelib/json/qjsondocument.cpp
+++ b/src/corelib/json/qjsondocument.cpp
@@ -317,10 +317,10 @@ QByteArray QJsonDocument::toJson() const
 
  \sa toJson
  */
-QJsonDocument QJsonDocument::fromJson(const QByteArray &json)
+QJsonDocument QJsonDocument::fromJson(const QByteArray &json, QJsonParseError *error)
 {
     QJsonPrivate::Parser parser(json.constData(), json.length());
-    return parser.parse();
+    return parser.parse(error);
 }
 
 /*!
diff --git a/src/corelib/json/qjsondocument.h b/src/corelib/json/qjsondocument.h
index 39db830726..7eca0302db 100644
--- a/src/corelib/json/qjsondocument.h
+++ b/src/corelib/json/qjsondocument.h
@@ -54,6 +54,26 @@ namespace QJsonPrivate {
     class Parser;
 }
 
+struct Q_CORE_EXPORT QJsonParseError
+{
+    enum ParseError {
+        NoError = 0,
+        UnterminatedObject,
+        MissingNameSeparator,
+        UnterminatedArray,
+        MissingValueSeparator,
+        IllegalValue,
+        EndOfNumber,
+        IllegalNumber,
+        StringEscapeSequence,
+        StringUTF8Scan,
+        EndOfString
+    };
+
+    int        offset;
+    ParseError error;
+};
+
 class Q_CORE_EXPORT QJsonDocument
 {
 public:
@@ -85,7 +105,7 @@ public:
     static QJsonDocument fromVariant(const QVariant &variant);
     QVariant toVariant() const;
 
-    static QJsonDocument fromJson(const QByteArray &json);
+    static QJsonDocument fromJson(const QByteArray &json, QJsonParseError *error = 0);
     QByteArray toJson() const;
 
     bool isEmpty() const;
diff --git a/src/corelib/json/qjsonparser.cpp b/src/corelib/json/qjsonparser.cpp
index 75ed7de48f..16eedadf1a 100644
--- a/src/corelib/json/qjsonparser.cpp
+++ b/src/corelib/json/qjsonparser.cpp
@@ -60,7 +60,7 @@ QT_BEGIN_NAMESPACE
 using namespace QJsonPrivate;
 
 Parser::Parser(const char *json, int length)
-    : json(json), data(0), dataLength(0), current(0)
+    : head(json), json(json), data(0), dataLength(0), current(0), lastError(QJsonParseError::NoError)
 {
     end = json + length;
 }
@@ -134,8 +134,6 @@ char Parser::nextToken()
     case BeginObject:
     case NameSeparator:
     case ValueSeparator:
-        if (!eatSpace())
-            return 0;
     case EndArray:
     case EndObject:
         eatSpace();
@@ -151,7 +149,7 @@ char Parser::nextToken()
 /*
     JSON-text = object / array
 */
-QJsonDocument Parser::parse()
+QJsonDocument Parser::parse(QJsonParseError *error)
 {
 #ifdef PARSER_DEBUG
     indent = 0;
@@ -182,6 +180,10 @@ QJsonDocument Parser::parse()
 
     END;
     {
+        if (error) {
+            error->offset = 0;
+            error->error = QJsonParseError::NoError;
+        }
         QJsonPrivate::Data *d = new QJsonPrivate::Data(data, current);
         return QJsonDocument(d);
     }
@@ -190,6 +192,10 @@ error:
 #ifdef PARSER_DEBUG
     qDebug() << ">>>>> parser error";
 #endif
+    if (error) {
+        error->offset = json - head;
+        error->error  = lastError;
+    }
     free(data);
     return QJsonDocument();
 }
@@ -241,8 +247,10 @@ bool Parser::parseObject()
     }
 
     DEBUG << "end token=" << token;
-    if (token != EndObject)
+    if (token != EndObject) {
+        lastError = QJsonParseError::UnterminatedObject;
         return false;
+    }
 
     DEBUG << "numEntries" << parsedObject.offsets.size();
     int table = objectOffset;
@@ -283,8 +291,10 @@ bool Parser::parseMember(int baseOffset)
     if (!parseString(&latin1))
         return false;
     char token = nextToken();
-    if (token != NameSeparator)
+    if (token != NameSeparator) {
+        lastError = QJsonParseError::MissingNameSeparator;
         return false;
+    }
     QJsonPrivate::Value val;
     if (!parseValue(&val, baseOffset))
         return false;
@@ -308,8 +318,10 @@ bool Parser::parseArray()
 
     QVarLengthArray<QJsonPrivate::Value> values;
 
-    if (!eatSpace())
+    if (!eatSpace()) {
+        lastError = QJsonParseError::UnterminatedArray;
         return false;
+    }
     if (*json == EndArray) {
         nextToken();
     } else {
@@ -321,8 +333,13 @@ bool Parser::parseArray()
             char token = nextToken();
             if (token == EndArray)
                 break;
-            else if (token != ValueSeparator)
+            else if (token != ValueSeparator) {
+                if (!eatSpace())
+                    lastError = QJsonParseError::UnterminatedArray;
+                else
+                    lastError = QJsonParseError::MissingValueSeparator;
                 return false;
+            }
         }
     }
 
@@ -358,8 +375,10 @@ bool Parser::parseValue(QJsonPrivate::Value *val, int baseOffset)
 
     switch (*json++) {
     case 'n':
-        if (end - json < 4)
+        if (end - json < 4) {
+            lastError = QJsonParseError::IllegalValue;
             return false;
+        }
         if (*json++ == 'u' &&
             *json++ == 'l' &&
             *json++ == 'l') {
@@ -368,10 +387,13 @@ bool Parser::parseValue(QJsonPrivate::Value *val, int baseOffset)
             END;
             return true;
         }
+        lastError = QJsonParseError::IllegalValue;
         return false;
     case 't':
-        if (end - json < 4)
+        if (end - json < 4) {
+            lastError = QJsonParseError::IllegalValue;
             return false;
+        }
         if (*json++ == 'r' &&
             *json++ == 'u' &&
             *json++ == 'e') {
@@ -381,10 +403,13 @@ bool Parser::parseValue(QJsonPrivate::Value *val, int baseOffset)
             END;
             return true;
         }
+        lastError = QJsonParseError::IllegalValue;
         return false;
     case 'f':
-        if (end - json < 5)
+        if (end - json < 5) {
+            lastError = QJsonParseError::IllegalValue;
             return false;
+        }
         if (*json++ == 'a' &&
             *json++ == 'l' &&
             *json++ == 's' &&
@@ -395,6 +420,7 @@ bool Parser::parseValue(QJsonPrivate::Value *val, int baseOffset)
             END;
             return true;
         }
+        lastError = QJsonParseError::IllegalValue;
         return false;
     case Quote: {
         val->type = QJsonValue::String;
@@ -490,8 +516,10 @@ bool Parser::parseNumber(QJsonPrivate::Value *val, int baseOffset)
             ++json;
     }
 
-    if (json >= end)
+    if (json >= end) {
+        lastError = QJsonParseError::EndOfNumber;
         return false;
+    }
 
     QByteArray number(start, json - start);
     DEBUG << "numberstring" << number;
@@ -514,8 +542,10 @@ bool Parser::parseNumber(QJsonPrivate::Value *val, int baseOffset)
     };
     d = number.toDouble(&ok);
 
-    if (!ok)
+    if (!ok) {
+        lastError = QJsonParseError::IllegalNumber;
         return false;
+    }
 
     int pos = reserveSpace(sizeof(double));
     *(quint64 *)(data + pos) = qToLittleEndian(ui);
@@ -679,11 +709,15 @@ bool Parser::parseString(bool *latin1)
         if (*json == '"')
             break;
         else if (*json == '\\') {
-            if (!scanEscapeSequence(json, end, &ch))
+            if (!scanEscapeSequence(json, end, &ch)) {
+                lastError = QJsonParseError::StringEscapeSequence;
                 return false;
+            }
         } else {
-            if (!scanUtf8Char(json, end, &ch))
+            if (!scanUtf8Char(json, end, &ch)) {
+                lastError = QJsonParseError::StringUTF8Scan;
                 return false;
+            }
         }
         if (ch > 0xff) {
             *latin1 = false;
@@ -695,8 +729,10 @@ bool Parser::parseString(bool *latin1)
     }
     ++json;
     DEBUG << "end of string";
-    if (json >= end)
+    if (json >= end) {
+        lastError = QJsonParseError::EndOfString;
         return false;
+    }
 
     // no unicode string, we are done
     if (*latin1) {
@@ -720,11 +756,15 @@ bool Parser::parseString(bool *latin1)
         if (*json == '"')
             break;
         else if (*json == '\\') {
-            if (!scanEscapeSequence(json, end, &ch))
+            if (!scanEscapeSequence(json, end, &ch)) {
+                lastError = QJsonParseError::StringEscapeSequence;
                 return false;
+            }
         } else {
-            if (!scanUtf8Char(json, end, &ch))
+            if (!scanUtf8Char(json, end, &ch)) {
+                lastError = QJsonParseError::StringUTF8Scan;
                 return false;
+            }
         }
         if (ch > 0xffff) {
             int pos = reserveSpace(4);
@@ -737,8 +777,10 @@ bool Parser::parseString(bool *latin1)
     }
     ++json;
 
-    if (json >= end)
+    if (json >= end) {
+        lastError = QJsonParseError::EndOfString;
         return false;
+    }
 
     // write string length
     *(QJsonPrivate::qle_int *)(data + stringPos) = (current - outStart - sizeof(int))/2;
diff --git a/src/corelib/json/qjsonparser_p.h b/src/corelib/json/qjsonparser_p.h
index eae6c08718..20e57dcf26 100644
--- a/src/corelib/json/qjsonparser_p.h
+++ b/src/corelib/json/qjsonparser_p.h
@@ -65,7 +65,7 @@ class Parser
 public:
     Parser(const char *json, int length);
 
-    QJsonDocument parse();
+    QJsonDocument parse(QJsonParseError *error);
 
     class ParsedObject
     {
@@ -93,12 +93,14 @@ private:
     bool parseString(bool *latin1);
     bool parseValue(QJsonPrivate::Value *val, int baseOffset);
     bool parseNumber(QJsonPrivate::Value *val, int baseOffset);
+    const char *head;
     const char *json;
     const char *end;
 
     char *data;
     int dataLength;
     int current;
+    QJsonParseError::ParseError lastError;
 
     inline int reserveSpace(int space) {
         if (current + space >= dataLength) {
diff --git a/tests/auto/corelib/json/tst_qtjson.cpp b/tests/auto/corelib/json/tst_qtjson.cpp
index 323546b8ea..2ac0574ec5 100644
--- a/tests/auto/corelib/json/tst_qtjson.cpp
+++ b/tests/auto/corelib/json/tst_qtjson.cpp
@@ -92,6 +92,7 @@ private Q_SLOTS:
 
     void toJson();
     void fromJson();
+    void fromJsonErrors();
     void fromBinary();
     void toAndFromBinary_data();
     void toAndFromBinary();
@@ -1080,6 +1081,170 @@ void TestQtJson::fromJson()
     }
 }
 
+void TestQtJson::fromJsonErrors()
+{
+    {
+        QJsonParseError error;
+        QByteArray json = "{\n    \n\n";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::UnterminatedObject);
+        QCOMPARE(error.offset, 8);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "{\n    \"key\" 10\n";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::MissingNameSeparator);
+        QCOMPARE(error.offset, 13);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n    \n\n";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::UnterminatedArray);
+        QCOMPARE(error.offset, 8);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n   1, true\n\n";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::UnterminatedArray);
+        QCOMPARE(error.offset, 14);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n  1 true\n\n";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::MissingValueSeparator);
+        QCOMPARE(error.offset, 7);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n    nul";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::IllegalValue);
+        QCOMPARE(error.offset, 7);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n    nulzz";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::IllegalValue);
+        QCOMPARE(error.offset, 10);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n    tru";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::IllegalValue);
+        QCOMPARE(error.offset, 7);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n    trud]";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::IllegalValue);
+        QCOMPARE(error.offset, 10);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n    fal";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::IllegalValue);
+        QCOMPARE(error.offset, 7);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n    falsd]";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::IllegalValue);
+        QCOMPARE(error.offset, 11);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n    11111";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::EndOfNumber);
+        QCOMPARE(error.offset, 11);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n    -1E10000]";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::IllegalNumber);
+        QCOMPARE(error.offset, 14);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n    -1e-10000]";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::IllegalNumber);
+        QCOMPARE(error.offset, 15);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n    \"\\u12\"]";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::StringEscapeSequence);
+        QCOMPARE(error.offset, 11);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n    \"foo\uffffbar\"]";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::StringUTF8Scan);
+        QCOMPARE(error.offset, 13);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n    \"";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::EndOfString);
+        QCOMPARE(error.offset, 8);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n    \"cЂa\\u12\"]";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::StringEscapeSequence);
+        QCOMPARE(error.offset, 15);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n    \"cЂa\uffffbar\"]";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::StringUTF8Scan);
+        QCOMPARE(error.offset, 14);
+    }
+    {
+        QJsonParseError error;
+        QByteArray json = "[\n    \"cЂa ]";
+        QJsonDocument doc = QJsonDocument::fromJson(json, &error);
+        QVERIFY(doc.isEmpty());
+        QCOMPARE(error.error, QJsonParseError::EndOfString);
+        QCOMPARE(error.offset, 14);
+    }
+}
+
 void TestQtJson::fromBinary()
 {
     QFile file(testDataDir + "/test.json");