jsexn.c

java script test programing source code

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sw=4 et tw=78:
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (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.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Communicator client code, released
 * March 31, 1998.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

/*
 * JS standard exception implementation.
 */

#include "jsstddef.h"
#include <stdlib.h>
#include <string.h>
#include "jstypes.h"
#include "jsbit.h"
#include "jsutil.h" /* Added by JSIFY */
#include "jsprf.h"
#include "jsapi.h"
#include "jscntxt.h"
#include "jsconfig.h"
#include "jsdbgapi.h"
#include "jsexn.h"
#include "jsfun.h"
#include "jsinterp.h"
#include "jsnum.h"
#include "jsopcode.h"
#include "jsscript.h"

/* Forward declarations for js_ErrorClass's initializer. */
static JSBool
Exception(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval);

static void
exn_finalize(JSContext *cx, JSObject *obj);

static uint32
exn_mark(JSContext *cx, JSObject *obj, void *arg);

static void
exn_finalize(JSContext *cx, JSObject *obj);

static JSBool
exn_enumerate(JSContext *cx, JSObject *obj);

static JSBool
exn_resolve(JSContext *cx, JSObject *obj, jsval id, uintN flags,
            JSObject **objp);

JSClass js_ErrorClass = {
    js_Error_str,
    JSCLASS_HAS_PRIVATE | JSCLASS_NEW_RESOLVE |
    JSCLASS_HAS_CACHED_PROTO(JSProto_Error),
    JS_PropertyStub,  JS_PropertyStub,  JS_PropertyStub,  JS_PropertyStub,
    exn_enumerate,    (JSResolveOp)exn_resolve, JS_ConvertStub, exn_finalize,
    NULL,             NULL,             NULL,             Exception,
    NULL,             NULL,             exn_mark,         NULL
};

typedef struct JSStackTraceElem {
    JSString            *funName;
    size_t              argc;
    const char          *filename;
    uintN               ulineno;
} JSStackTraceElem;

typedef struct JSExnPrivate {
    /* A copy of the JSErrorReport originally generated. */
    JSErrorReport       *errorReport;
    JSString            *message;
    JSString            *filename;
    uintN               lineno;
    size_t              stackDepth;
    JSStackTraceElem    stackElems[1];
} JSExnPrivate;

static JSString *
StackTraceToString(JSContext *cx, JSExnPrivate *priv);

static JSErrorReport *
CopyErrorReport(JSContext *cx, JSErrorReport *report)
{
    /*
     * We use a single malloc block to make a deep copy of JSErrorReport with
     * the following layout:
     *   JSErrorReport
     *   array of copies of report->messageArgs
     *   jschar array with characters for all messageArgs
     *   jschar array with characters for ucmessage
     *   jschar array with characters for uclinebuf and uctokenptr
     *   char array with characters for linebuf and tokenptr
     *   char array with characters for filename
     * Such layout together with the properties enforced by the following
     * asserts does not need any extra alignment padding.
     */
//    JS_STATIC_ASSERT(sizeof(JSErrorReport) % sizeof(const char *) == 0);
//    JS_STATIC_ASSERT(sizeof(const char *) % sizeof(jschar) == 0);

    size_t filenameSize;
    size_t linebufSize;
    size_t uclinebufSize;
    size_t ucmessageSize;
    size_t i, argsArraySize, argsCopySize, argSize;
    size_t mallocSize;
    JSErrorReport *copy;
    uint8 *cursor;

#define JS_CHARS_SIZE(jschars) ((js_strlen(jschars) + 1) * sizeof(jschar))

    filenameSize = report->filename ? strlen(report->filename) + 1 : 0;
    linebufSize = report->linebuf ? strlen(report->linebuf) + 1 : 0;
    uclinebufSize = report->uclinebuf ? JS_CHARS_SIZE(report->uclinebuf) : 0;
    ucmessageSize = 0;
    argsArraySize = 0;
    argsCopySize = 0;
    if (report->ucmessage) {
        ucmessageSize = JS_CHARS_SIZE(report->ucmessage);
        if (report->messageArgs) {
            for (i = 0; report->messageArgs[i]; ++i)
                argsCopySize += JS_CHARS_SIZE(report->messageArgs[i]);

            /* Non-null messageArgs should have at least one non-null arg. */
            JS_ASSERT(i != 0);
            argsArraySize = (i + 1) * sizeof(const jschar *);
        }
    }

    /*
     * The mallocSize can not overflow since it represents the sum of the
     * sizes of already allocated objects.
     */
    mallocSize = sizeof(JSErrorReport) + argsArraySize + argsCopySize +
                 ucmessageSize + uclinebufSize + linebufSize + filenameSize;
    cursor = (uint8 *)JS_malloc(cx, mallocSize);
    if (!cursor)
        return NULL;

    copy = (JSErrorReport *)cursor;
    memset(cursor, 0, sizeof(JSErrorReport));
    cursor += sizeof(JSErrorReport);

    if (argsArraySize != 0) {
        copy->messageArgs = (const jschar **)cursor;
        cursor += argsArraySize;
        for (i = 0; report->messageArgs[i]; ++i) {
            copy->messageArgs[i] = (const jschar *)cursor;
            argSize = JS_CHARS_SIZE(report->messageArgs[i]);
            memcpy(cursor, report->messageArgs[i], argSize);
            cursor += argSize;
        }
        copy->messageArgs[i] = NULL;
        JS_ASSERT(cursor == (uint8 *)copy->messageArgs[0] + argsCopySize);
    }

    if (report->ucmessage) {
        copy->ucmessage = (const jschar *)cursor;
        memcpy(cursor, report->ucmessage, ucmessageSize);
        cursor += ucmessageSize;
    }

    if (report->uclinebuf) {
        copy->uclinebuf = (const jschar *)cursor;
        memcpy(cursor, report->uclinebuf, uclinebufSize);
        cursor += uclinebufSize;
        if (report->uctokenptr) {
            copy->uctokenptr = copy->uclinebuf + (report->uctokenptr -
                                                  report->uclinebuf);
        }
    }

    if (report->linebuf) {
        copy->linebuf = (const char *)cursor;
        memcpy(cursor, report->linebuf, linebufSize);
        cursor += linebufSize;
        if (report->tokenptr) {
            copy->tokenptr = copy->linebuf + (report->tokenptr -
                                              report->linebuf);
        }
    }

    if (report->filename) {
        copy->filename = (const char *)cursor;
        memcpy(cursor, report->filename, filenameSize);
    }
    JS_ASSERT(cursor + filenameSize == (uint8 *)copy + mallocSize);

    /* Copy non-pointer members. */
    copy->lineno = report->lineno;
    copy->errorNumber = report->errorNumber;

    /* Note that this is before it gets flagged with JSREPORT_EXCEPTION */
    copy->flags = report->flags;

#undef JS_CHARS_SIZE
    return copy;
}

static jsval *
GetStackTraceValueBuffer(JSExnPrivate *priv)
{
    /*
     * We use extra memory after JSExnPrivateInfo.stackElems to store jsvals
     * that helps to produce more informative stack traces. The following
     * assert allows us to assume that no gap after stackElems is necessary to
     * align the buffer properly.
     */
//    JS_STATIC_ASSERT(sizeof(JSStackTraceElem) % sizeof(jsval) == 0);

    return (jsval *)(priv->stackElems + priv->stackDepth);
}

static JSBool
InitExnPrivate(JSContext *cx, JSObject *exnObject, JSString *message,
               JSString *filename, uintN lineno, JSErrorReport *report)
{
    JSCheckAccessOp checkAccess;
    JSErrorReporter older;
    JSExceptionState *state;
    jsval callerid, v;
    JSStackFrame *fp, *fpstop;
    size_t stackDepth, valueCount, size;
    JSBool overflow;
    JSExnPrivate *priv;
    JSStackTraceElem *elem;
    jsval *values;

    JS_ASSERT(OBJ_GET_CLASS(cx, exnObject) == &js_ErrorClass);

    /*
     * Prepare stack trace data.
     *
     * Set aside any error reporter for cx and save its exception state
     * so we can suppress any checkAccess failures.  Such failures should stop
     * the backtrace procedure, not result in a failure of this constructor.
     */
    checkAccess = cx->runtime->checkObjectAccess;
    older = JS_SetErrorReporter(cx, NULL);
    state = JS_SaveExceptionState(cx);

    callerid = ATOM_KEY(cx->runtime->atomState.callerAtom);
    stackDepth = 0;
    valueCount = 0;
    for (fp = cx->fp; fp; fp = fp->down) {
        if (fp->fun && fp->argv) {
            if (checkAccess) {
                v = fp->argv[-2];
                if (!JSVAL_IS_PRIMITIVE(v) &&
                    !checkAccess(cx, JSVAL_TO_OBJECT(v), callerid,
                                 JSACC_READ, &v /* ignored */)) {
                    break;
                }
            }
            valueCount += fp->argc;
        }
        ++stackDepth;
    }
    JS_RestoreExceptionState(cx, state);
    JS_SetErrorReporter(cx, older);
    fpstop = fp;

    size = offsetof(JSExnPrivate, stackElems);
    overflow = (stackDepth > ((size_t)-1 - size) / sizeof(JSStackTraceElem));
    size += stackDepth * sizeof(JSStackTraceElem);
    overflow |= (valueCount > ((size_t)-1 - size) / sizeof(jsval));
    size += valueCount * sizeof(jsval);
    if (overflow) {
        JS_ReportOutOfMemory(cx);
        return JS_FALSE;
    }
    priv = (JSExnPrivate *)JS_malloc(cx, size);
    if (!priv)
        return JS_FALSE;

    /*
     * We initialize errorReport with a copy of report after setting the
     * private slot, to prevent GC accessing a junk value we clear the field
     * here.
     */
    priv->errorReport = NULL;
    priv->message = message;
    priv->filename = filename;
    priv->lineno = lineno;
    priv->stackDepth = stackDepth;

    values = GetStackTraceValueBuffer(priv);
    elem = priv->stackElems;
    for (fp = cx->fp; fp != fpstop; fp = fp->down) {
        if (!fp->fun) {
            elem->funName = NULL;
            elem->argc = 0;
        } else {
            elem->funName = fp->fun->atom
                            ? ATOM_TO_STRING(fp->fun->atom)
                            : cx->runtime->emptyString;
            elem->argc = fp->argc;
            memcpy(values, fp->argv, fp->argc * sizeof(jsval));
            values += fp->argc;
        }
        elem->ulineno = 0;
        elem->filename = NULL;
        if (fp->script) {
            elem->filename = fp->script->filename;
            if (fp->pc)
                elem->ulineno = js_PCToLineNumber(cx, fp->script, fp->pc);
        }
        ++elem;
    }
    JS_ASSERT(priv->stackElems + stackDepth == elem);
    JS_ASSERT(GetStackTraceValueBuffer(priv) + valueCount == values);

    OBJ_SET_SLOT(cx, exnObject, JSSLOT_PRIVATE, PRIVATE_TO_JSVAL(priv));

    if (report) {
        /*
         * Construct a new copy of the error report struct. We can't use the
         * error report struct that was passed in, because it's allocated on
         * the stack, and also because it may point to transient data in the
         * JSTokenStream.
         */
        priv->errorReport = CopyErrorReport(cx, report);
        if (!priv->errorReport) {
            /* The finalizer realeases priv since it is in the private slot. */
            return JS_FALSE;
        }
    }

    return JS_TRUE;
}

static JSExnPrivate *
GetExnPrivate(JSContext *cx, JSObject *obj)
{
    jsval privateValue;
    JSExnPrivate *priv;

    JS_ASSERT(OBJ_GET_CLASS(cx, obj) == &js_ErrorClass);
    privateValue = OBJ_GET_SLOT(cx, obj, JSSLOT_PRIVATE);
    if (JSVAL_IS_VOID(privateValue))
        return NULL;
    priv = (JSExnPrivate *)JSVAL_TO_PRIVATE(privateValue);
    JS_ASSERT(priv);
    return priv;
}

static uint32
exn_mark(JSContext *cx, JSObject *obj, void *arg)
{
    JSExnPrivate *priv;
    JSStackTraceElem *elem;
    size_t vcount, i;
    jsval *vp, v;

    priv = GetExnPrivate(cx, obj);
    if (priv) {
        GC_MARK(cx, priv->message, "exception message");
        GC_MARK(cx, priv->filename, "exception filename");
        elem = priv->stackElems;
        for (vcount = i = 0; i != priv->stackDepth; ++i, ++elem) {
            if (elem->funName)
                GC_MARK(cx, elem->funName, "stack trace function name");
            if (elem->filename)
                js_MarkScriptFilename(elem->filename);
            vcount += elem->argc;
        }
        vp = GetStackTraceValueBuffer(priv);
        for (i = 0; i != vcount; ++i, ++vp) {
            v = *vp;
            if (JSVAL_IS_GCTHING(v))
                GC_MARK(cx, JSVAL_TO_GCTHING(v), "stack trace argument");
        }
    }
    return 0;
}

static void
exn_finalize(JSContext *cx, JSObject *obj)
{
    JSExnPrivate *priv;

    priv = GetExnPrivate(cx, obj);
    if (priv) {
        if (priv->errorReport)
            JS_free(cx, priv->errorReport);
        JS_free(cx, priv);
    }
}

static JSBool
exn_enumerate(JSContext *cx, JSObject *obj)
{
    JSAtomState *atomState;
    uintN i;
    JSAtom *atom;
    JSObject *pobj;
    JSProperty *prop;
    
//    JS_STATIC_ASSERT(sizeof(JSAtomState) <= (size_t)(uint16)-1);
    static const uint16 offsets[] = {
        (uint16)offsetof(JSAtomState, messageAtom),
        (uint16)offsetof(JSAtomState, fileNameAtom),
        (uint16)offsetof(JSAtomState, lineNumberAtom),
        (uint16)offsetof(JSAtomState, stackAtom),
    };

    atomState = &cx->runtime->atomState;
    for (i = 0; i != JS_ARRAY_LENGTH(offsets); ++i) {
        atom = *(JSAtom **)((uint8 *)atomState + offsets[i]); 
        if (!js_LookupProperty(cx, obj, ATOM_TO_JSID(atom), &pobj, &prop))
            return JS_FALSE;
        if (prop)
            OBJ_DROP_PROPERTY(cx, pobj, prop);
    }
    return JS_TRUE;
}

static JSBool
exn_resolve(JSContext *cx, JSObject *obj, jsval id, uintN flags,