michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0:  * vim: set ts=8 sts=4 et sw=4 tw=99:
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef jsonparser_h
michael@0: #define jsonparser_h
michael@0: 
michael@0: #include "mozilla/Attributes.h"
michael@0: 
michael@0: #include "ds/IdValuePair.h"
michael@0: #include "vm/String.h"
michael@0: 
michael@0: namespace js {
michael@0: 
michael@0: class MOZ_STACK_CLASS JSONParser : private AutoGCRooter
michael@0: {
michael@0:   public:
michael@0:     enum ErrorHandling { RaiseError, NoError };
michael@0: 
michael@0:   private:
michael@0:     /* Data members */
michael@0: 
michael@0:     JSContext * const cx;
michael@0:     JS::ConstTwoByteChars current;
michael@0:     const JS::ConstTwoByteChars begin, end;
michael@0: 
michael@0:     Value v;
michael@0: 
michael@0:     const ErrorHandling errorHandling;
michael@0: 
michael@0:     enum Token { String, Number, True, False, Null,
michael@0:                  ArrayOpen, ArrayClose,
michael@0:                  ObjectOpen, ObjectClose,
michael@0:                  Colon, Comma,
michael@0:                  OOM, Error };
michael@0: 
michael@0:     // State related to the parser's current position. At all points in the
michael@0:     // parse this keeps track of the stack of arrays and objects which have
michael@0:     // been started but not finished yet. The actual JS object is not
michael@0:     // allocated until the literal is closed, so that the result can be sized
michael@0:     // according to its contents and have its type and shape filled in using
michael@0:     // caches.
michael@0: 
michael@0:     // State for an array that is currently being parsed. This includes all
michael@0:     // elements that have been seen so far.
michael@0:     typedef Vector<Value, 20> ElementVector;
michael@0: 
michael@0:     // State for an object that is currently being parsed. This includes all
michael@0:     // the key/value pairs that have been seen so far.
michael@0:     typedef Vector<IdValuePair, 10> PropertyVector;
michael@0: 
michael@0:     // Possible states the parser can be in between values.
michael@0:     enum ParserState {
michael@0:         // An array element has just being parsed.
michael@0:         FinishArrayElement,
michael@0: 
michael@0:         // An object property has just been parsed.
michael@0:         FinishObjectMember,
michael@0: 
michael@0:         // At the start of the parse, before any values have been processed.
michael@0:         JSONValue
michael@0:     };
michael@0: 
michael@0:     // Stack element for an in progress array or object.
michael@0:     struct StackEntry {
michael@0:         ElementVector &elements() {
michael@0:             JS_ASSERT(state == FinishArrayElement);
michael@0:             return * static_cast<ElementVector *>(vector);
michael@0:         }
michael@0: 
michael@0:         PropertyVector &properties() {
michael@0:             JS_ASSERT(state == FinishObjectMember);
michael@0:             return * static_cast<PropertyVector *>(vector);
michael@0:         }
michael@0: 
michael@0:         StackEntry(ElementVector *elements)
michael@0:           : state(FinishArrayElement), vector(elements)
michael@0:         {}
michael@0: 
michael@0:         StackEntry(PropertyVector *properties)
michael@0:           : state(FinishObjectMember), vector(properties)
michael@0:         {}
michael@0: 
michael@0:         ParserState state;
michael@0: 
michael@0:       private:
michael@0:         void *vector;
michael@0:     };
michael@0: 
michael@0:     // All in progress arrays and objects being parsed, in order from outermost
michael@0:     // to innermost.
michael@0:     Vector<StackEntry, 10> stack;
michael@0: 
michael@0:     // Unused element and property vectors for previous in progress arrays and
michael@0:     // objects. These vectors are not freed until the end of the parse to avoid
michael@0:     // unnecessary freeing and allocation.
michael@0:     Vector<ElementVector*, 5> freeElements;
michael@0:     Vector<PropertyVector*, 5> freeProperties;
michael@0: 
michael@0: #ifdef DEBUG
michael@0:     Token lastToken;
michael@0: #endif
michael@0: 
michael@0:   public:
michael@0:     /* Public API */
michael@0: 
michael@0:     /* Create a parser for the provided JSON data. */
michael@0:     JSONParser(JSContext *cx, JS::ConstTwoByteChars data, size_t length,
michael@0:                ErrorHandling errorHandling = RaiseError)
michael@0:       : AutoGCRooter(cx, JSONPARSER),
michael@0:         cx(cx),
michael@0:         current(data),
michael@0:         begin(data),
michael@0:         end((data + length).get(), data.get(), length),
michael@0:         errorHandling(errorHandling),
michael@0:         stack(cx),
michael@0:         freeElements(cx),
michael@0:         freeProperties(cx)
michael@0: #ifdef DEBUG
michael@0:       , lastToken(Error)
michael@0: #endif
michael@0:     {
michael@0:         JS_ASSERT(current <= end);
michael@0:     }
michael@0: 
michael@0:     ~JSONParser();
michael@0: 
michael@0:     /*
michael@0:      * Parse the JSON data specified at construction time.  If it parses
michael@0:      * successfully, store the prescribed value in *vp and return true.  If an
michael@0:      * internal error (e.g. OOM) occurs during parsing, return false.
michael@0:      * Otherwise, if invalid input was specifed but no internal error occurred,
michael@0:      * behavior depends upon the error handling specified at construction: if
michael@0:      * error handling is RaiseError then throw a SyntaxError and return false,
michael@0:      * otherwise return true and set *vp to |undefined|.  (JSON syntax can't
michael@0:      * represent |undefined|, so the JSON data couldn't have specified it.)
michael@0:      */
michael@0:     bool parse(MutableHandleValue vp);
michael@0: 
michael@0:   private:
michael@0:     Value numberValue() const {
michael@0:         JS_ASSERT(lastToken == Number);
michael@0:         JS_ASSERT(v.isNumber());
michael@0:         return v;
michael@0:     }
michael@0: 
michael@0:     Value stringValue() const {
michael@0:         JS_ASSERT(lastToken == String);
michael@0:         JS_ASSERT(v.isString());
michael@0:         return v;
michael@0:     }
michael@0: 
michael@0:     JSAtom *atomValue() const {
michael@0:         Value strval = stringValue();
michael@0:         return &strval.toString()->asAtom();
michael@0:     }
michael@0: 
michael@0:     Token token(Token t) {
michael@0:         JS_ASSERT(t != String);
michael@0:         JS_ASSERT(t != Number);
michael@0: #ifdef DEBUG
michael@0:         lastToken = t;
michael@0: #endif
michael@0:         return t;
michael@0:     }
michael@0: 
michael@0:     Token stringToken(JSString *str) {
michael@0:         this->v = StringValue(str);
michael@0: #ifdef DEBUG
michael@0:         lastToken = String;
michael@0: #endif
michael@0:         return String;
michael@0:     }
michael@0: 
michael@0:     Token numberToken(double d) {
michael@0:         this->v = NumberValue(d);
michael@0: #ifdef DEBUG
michael@0:         lastToken = Number;
michael@0: #endif
michael@0:         return Number;
michael@0:     }
michael@0: 
michael@0:     enum StringType { PropertyName, LiteralValue };
michael@0:     template<StringType ST> Token readString();
michael@0: 
michael@0:     Token readNumber();
michael@0: 
michael@0:     Token advance();
michael@0:     Token advancePropertyName();
michael@0:     Token advancePropertyColon();
michael@0:     Token advanceAfterProperty();
michael@0:     Token advanceAfterObjectOpen();
michael@0:     Token advanceAfterArrayElement();
michael@0: 
michael@0:     void error(const char *msg);
michael@0:     bool errorReturn();
michael@0: 
michael@0:     JSObject *createFinishedObject(PropertyVector &properties);
michael@0:     bool finishObject(MutableHandleValue vp, PropertyVector &properties);
michael@0:     bool finishArray(MutableHandleValue vp, ElementVector &elements);
michael@0: 
michael@0:     void getTextPosition(uint32_t *column, uint32_t *line);
michael@0: 
michael@0:     friend void AutoGCRooter::trace(JSTracer *trc);
michael@0:     void trace(JSTracer *trc);
michael@0: 
michael@0:   private:
michael@0:     JSONParser(const JSONParser &other) MOZ_DELETE;
michael@0:     void operator=(const JSONParser &other) MOZ_DELETE;
michael@0: };
michael@0: 
michael@0: } /* namespace js */
michael@0: 
michael@0: #endif /* jsonparser_h */