Changeset 44343 in webkit for trunk/JavaScriptCore/runtime/LiteralParser.cpp

Timestamp:

Jun 1, 2009, 9:40:16 PM (16 years ago)

Author:

[email protected]

Message:

Tidy up the literal parser.

Reviewed by Gavin Barraclogh.

Make the number lexing in the LiteralParser exactly match the JSON spec, which
makes us cover more cases, but also more strict. Also made string lexing only
allow double-quoted strings.

File:

• trunk/JavaScriptCore/runtime/LiteralParser.cpp (modified) (3 diffs)

trunk/JavaScriptCore/runtime/LiteralParser.cpp

@@ -101 +101 @@
             return TokColon;
         case '"':
-        case '\'':
             return lexString(token);
 
-        // Numbers are trickier so we only allow the most basic form, basically
-        // * [1-9][0-9]*(\.[0-9]*)?
-        // * \.[0-9]*
-        // * 0(\.[0-9]*)?
+        case '-':
         case '0':
-            // If a number starts with 0 it's expected to be octal.  It seems silly
-            // to attempt to handle this case, so we abort
-            if (m_ptr < m_end - 1 && isASCIIDigit(m_ptr[1]))
-                return TokError;
-            return lexNumber(token);
-        case '.':
-            // If a number starts with a '.' it must be followed by a digit
-            if (!(m_ptr < m_end - 1 && isASCIIDigit(m_ptr[1])))
-                return TokError;
-            return lexNumber(token);
         case '1':
         case '2':
@@ -135 +121 @@
 LiteralParser::TokenType LiteralParser::Lexer::lexString(LiteralParserToken& token)
 {
-    UChar terminator = *m_ptr;
     ++m_ptr;
-    while (m_ptr < m_end && isSafeStringCharacter(*m_ptr) && *m_ptr != terminator)
-        ++m_ptr;
-    if (m_ptr >= m_end || *m_ptr != terminator) {
+    while (m_ptr < m_end && isSafeStringCharacter(*m_ptr) && *m_ptr != '"')
+        ++m_ptr;
+    if (m_ptr >= m_end || *m_ptr != '"') {
         token.type = TokError;
         token.end = ++m_ptr;
@@ -151 +136 @@
 LiteralParser::TokenType LiteralParser::Lexer::lexNumber(LiteralParserToken& token)
 {
-    bool beginsWithDot = *m_ptr == '.';
-    ++m_ptr;
-    while (m_ptr < m_end && isASCIIDigit(*m_ptr))
-        ++m_ptr;
-
-    if (!beginsWithDot && m_ptr < m_end - 1 && *m_ptr == '.') {
-        ++m_ptr;
+    // ES5 and json.org define numbers as
+    // number
+    //     int
+    //     int frac? exp?
+    //
+    // int
+    //     -? 0
+    //     -? digit1-9 digits?
+    //
+    // digits
+    //     digit digits?
+    //
+    // -?(0 | [1-9][0-9]*) ('.' [0-9]+)? ([eE][+-]? [0-9]+)?
+
+    if (m_ptr < m_end && *m_ptr == '-') // -?
+        ++m_ptr;
+    
+    // (0 | [1-9][0-9]*)
+    if (m_ptr < m_end && *m_ptr == '0') // 0
+        ++m_ptr;
+    else if (m_ptr < m_end && *m_ptr >= '1' && *m_ptr <= '9') { // [1-9]
+        ++m_ptr;
+        // [0-9]*
         while (m_ptr < m_end && isASCIIDigit(*m_ptr))
             ++m_ptr;
-    }
-
-    if (m_ptr < m_end) {
-        if (*m_ptr == 'x' || *m_ptr == 'X' || *m_ptr == 'e' || *m_ptr == 'E') {
-            token.type = TokError;
+    } else
+        return TokError;
+
+    // ('.' [0-9]+)?
+    if (m_ptr < m_end && *m_ptr == '.') {
+        ++m_ptr;
+        // [0-9]+
+        if (m_ptr >= m_end && !isASCIIDigit(*m_ptr))
             return TokError;
-        }
-    }
+
+        ++m_ptr;
+        while (m_ptr < m_end && isASCIIDigit(*m_ptr))
+            ++m_ptr;
+    }
+
+    //  ([eE][+-]? [0-9]+)?
+    if (m_ptr < m_end && (*m_ptr == 'e' || *m_ptr == 'E')) { // [eE]
+        ++m_ptr;
+
+        // [-+]?
+        if (m_ptr < m_end && (*m_ptr == '-' || *m_ptr == '+'))
+            ++m_ptr;
+
+        // [0-9]+
+        if (m_ptr >= m_end && !isASCIIDigit(*m_ptr))
+            return TokError;
+        
+        ++m_ptr;
+        while (m_ptr < m_end && isASCIIDigit(*m_ptr))
+            ++m_ptr;
+    }
+    
     token.type = TokNumber;
     token.end = m_ptr;