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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
/* $Rev$ $Date$ */
#ifndef tuscany_json_hpp
#define tuscany_json_hpp
/**
* JSON data conversion functions.
*/
#include "string.hpp"
#include "list.hpp"
#include "value.hpp"
#include "element.hpp"
#include "monad.hpp"
#include "../js/eval.hpp"
namespace tuscany {
namespace json {
/**
* Return true if a list of strings contains a JSON document.
*/
const bool isJSON(const list<string>& ls) {
if (isNil(ls))
return false;
const string s = substr(car(ls), 0, 1);
return s == "[" || s == "{";
}
/**
* Consumes JSON strings and populates a JS object.
*/
failable<bool> consume(JSONParser* parser, const list<string>& ilist, const js::JSContext& cx) {
if (isNil(ilist))
return true;
JSString* jstr = JS_NewStringCopyZ(cx, c_str(car(ilist)));
if(!JS_ConsumeJSONText(cx, parser, JS_GetStringCharsZ(cx, jstr), (uint32)JS_GetStringLength(jstr)))
return mkfailure<bool>("JS_ConsumeJSONText failed");
return consume(parser, cdr(ilist), cx);
}
/**
* Convert a list of strings representing a JSON document to a list of values.
*/
const failable<list<value> > readJSON(const list<string>& ilist, const js::JSContext& cx) {
jsval val;
JSONParser* parser = JS_BeginJSONParse(cx, &val);
if(parser == NULL)
return mkfailure<list<value> >("JS_BeginJSONParse failed");
const failable<bool> consumed = consume(parser, ilist, cx);
if(!JS_FinishJSONParse(cx, parser, JSVAL_NULL))
return mkfailure<list<value> >("JS_FinishJSONParse failed");
if(!hasContent(consumed))
return mkfailure<list<value> >(consumed);
return list<value>(js::jsValToValue(val, cx));
}
/**
* Context passed to the JSON write callback function.
*/
template<typename R> class WriteContext {
public:
WriteContext(const lambda<R(const string&, const R)>& reduce, const R& accum, const js::JSContext& cx) : cx(cx), reduce(reduce), accum(accum) {
}
const js::JSContext& cx;
const lambda<R(const string&, const R)> reduce;
R accum;
};
/**
* Called by JS_Stringify to write JSON out.
*/
template<typename R> JSBool writeCallback(const jschar *buf, uint32 len, void *data) {
WriteContext<R>& wcx = *(static_cast<WriteContext<R>*> (data));
JSString* jstr = JS_NewUCStringCopyN(wcx.cx, buf, len);
char* cstr = JS_EncodeString(wcx.cx, jstr);
const string str(cstr, JS_GetStringLength(jstr));
JS_free(wcx.cx, cstr);
wcx.accum = wcx.reduce(str, wcx.accum);
return JS_TRUE;
}
/**
* Convert a list of values to a JSON document.
*/
template<typename R> const failable<R> writeJSON(const lambda<R(const string&, const R)>& reduce, const R& initial, const list<value>& l, const js::JSContext& cx) {
jsval val;
if (js::isJSArray(l))
val = OBJECT_TO_JSVAL(valuesToJSElements(JS_NewArrayObject(cx, 0, NULL), l, 0, cx));
else
val = OBJECT_TO_JSVAL(valuesToJSProperties(JS_NewObject(cx, NULL, NULL, NULL), l, cx));
WriteContext<R> wcx(reduce, initial, cx);
if (!JS_Stringify(cx, &val, NULL, INT_TO_JSVAL(1), writeCallback<R>, &wcx))
return mkfailure<R>("JS_Stringify failed");
return wcx.accum;
}
/**
* Convert a list of values to a list of strings representing a JSON document.
*/
const failable<list<string> > writeJSON(const list<value>& l, const js::JSContext& cx) {
const failable<list<string> > ls = writeJSON<list<string>>(rcons<string>, list<string>(), valuesToElements(elementsToValues(l)), cx);
if (!hasContent(ls))
return ls;
return reverse(list<string>(content(ls)));
}
/**
* Convert a list of function + params to a JSON-RPC request.
*/
const failable<list<string> > jsonRequest(const value& id, const value& func, const value& params, js::JSContext& cx) {
const list<value> r = mklist<value>(mklist<value>("id", id), mklist<value>("method", string(func)), mklist<value>("params", params));
return writeJSON(valuesToElements(r), cx);
}
/**
* Convert a value to a JSON-RPC result.
*/
const failable<list<string> > jsonResult(const value& id, const value& val, js::JSContext& cx) {
return writeJSON(valuesToElements(mklist<value>(mklist<value>("id", id), mklist<value>("result", val))), cx);
}
/**
* Convert a JSON-RPC result to a value.
*/
const failable<value> jsonResultValue(const list<string>& s, js::JSContext& cx) {
const failable<list<value> > jsres = json::readJSON(s, cx);
if (!hasContent(jsres))
return mkfailure<value>(jsres);
const list<value> rval(cadr<value>(elementsToValues(content(jsres))));
const value val = cadr(rval);
if (isList(val) && !js::isJSArray(val))
return value(mklist<value>(val));
return val;
}
/**
* Convert a JSON payload to a list of values.
*/
const list<value> jsonValues(const list<value>& e) {
return elementsToValues(e);
}
/**
* Return a portable function name from a JSON-RPC function name.
* Strip the ".", "system." and "Service." prefixes added by some JSON-RPC clients.
*/
const string funcName(const string& f) {
if (length(f) > 1 && find(f, ".", 0) == 0)
return c_str(f) + 1;
if (length(f) > 7 && find(f, "system.", 0) == 0)
return c_str(f) + 7;
if (length(f) > 8 && find(f, "Service.", 0) == 0)
return c_str(f) + 8;
return f;
}
/**
* Returns a list of param values other than the id and method args from a list
* of key value pairs.
*/
const list<value> queryParams(const list<list<value> >& a) {
if (isNil(a))
return list<value>();
const list<value> p = car(a);
if (car(p) == value("id") || car(p) == value("method"))
return queryParams(cdr(a));
return cons(cadr(p), queryParams(cdr(a)));
}
}
}
#endif /* tuscany_json_hpp */
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