mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-11-14 15:37:55 +00:00
385 lines
13 KiB
JavaScript
385 lines
13 KiB
JavaScript
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
|
|
* vim: set ts=8 sw=4 et tw=78:
|
|
*
|
|
* jorendb - A toy command-line debugger for shell-js programs.
|
|
*
|
|
* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
/*
|
|
* jorendb is a simple command-line debugger for shell-js programs. It is
|
|
* intended as a demo of the Debugger object (as there are no shell js programs to
|
|
* speak of).
|
|
*
|
|
* To run it: $JS -d path/to/this/file/jorendb.js
|
|
* To run some JS code under it, try:
|
|
* (jorendb) print load("my-script-to-debug.js")
|
|
* Execution will stop at debugger statements and you'll get a jorendb prompt.
|
|
*/
|
|
|
|
(function () {
|
|
var debuggerSource = "(" + function () {
|
|
// Debugger state.
|
|
var focusedFrame = null;
|
|
var topFrame = null;
|
|
var debuggeeValues = [null];
|
|
var lastExc = null;
|
|
|
|
// Convert a debuggee value v to a string.
|
|
function dvToString(v) {
|
|
return (typeof v !== 'object' || v === null) ? uneval(v) : "[object " + v.class + "]";
|
|
}
|
|
|
|
function showDebuggeeValue(dv) {
|
|
var dvrepr = dvToString(dv);
|
|
var i = debuggeeValues.length;
|
|
debuggeeValues[i] = dv;
|
|
print("$" + i + " = " + dvrepr);
|
|
}
|
|
|
|
Object.defineProperty(Debugger.Frame.prototype, "num", {
|
|
configurable: true,
|
|
enumerable: false,
|
|
get: function () {
|
|
var i = 0;
|
|
for (var f = topFrame; f && f !== this; f = f.older)
|
|
i++;
|
|
return f === null ? undefined : i;
|
|
}
|
|
});
|
|
|
|
function framePosition(f) {
|
|
if (!f.script)
|
|
return f.type + " code";
|
|
return (f.script.url || f.type + " code") + ":" + f.script.getOffsetLine(f.offset);
|
|
}
|
|
|
|
function callDescription(f) {
|
|
return ((f.callee.name || '<anonymous>') +
|
|
"(" + f.arguments.map(dvToString).join(", ") + ")");
|
|
}
|
|
|
|
function showFrame(f, n) {
|
|
if (f === undefined || f === null) {
|
|
f = focusedFrame;
|
|
if (f === null) {
|
|
print("No stack.");
|
|
return;
|
|
}
|
|
}
|
|
if (n === undefined) {
|
|
n = f.num;
|
|
if (n === undefined)
|
|
throw new Error("Internal error: frame not on stack");
|
|
}
|
|
|
|
var me = '#' + n;
|
|
if (f.type === "call")
|
|
me += ' ' + callDescription(f);
|
|
me += ' ' + framePosition(f);
|
|
print(me);
|
|
}
|
|
|
|
function saveExcursion(fn) {
|
|
var tf = topFrame, ff = focusedFrame;
|
|
try {
|
|
return fn();
|
|
} finally {
|
|
topFrame = tf;
|
|
focusedFrame = ff;
|
|
}
|
|
}
|
|
|
|
function quitCommand() {
|
|
dbg.enabled = false;
|
|
quit(0);
|
|
}
|
|
|
|
function backtraceCommand() {
|
|
if (topFrame === null)
|
|
print("No stack.");
|
|
for (var i = 0, f = topFrame; f; i++, f = f.older)
|
|
showFrame(f, i);
|
|
}
|
|
|
|
function printCommand(rest) {
|
|
if (focusedFrame === null) {
|
|
// This is super bogus, need a way to create an env wrapping the debuggeeGlobal
|
|
// and eval against that.
|
|
var nonwrappedValue;
|
|
try {
|
|
nonwrappedValue = debuggeeGlobal.eval(rest);
|
|
} catch (exc) {
|
|
print("Exception caught.");
|
|
nonwrappedValue = exc;
|
|
}
|
|
if (typeof nonwrappedValue !== "object" || nonwrappedValue === null) {
|
|
// primitive value, no sweat
|
|
print(" " + uneval(nonwrappedValue));
|
|
} else {
|
|
// junk for now
|
|
print(" " + Object.prototype.toString.call(nonwrappedValue));
|
|
}
|
|
} else {
|
|
// This is the real deal.
|
|
var cv = saveExcursion(function () {
|
|
return focusedFrame.eval(rest);
|
|
});
|
|
if (cv === null) {
|
|
if (!dbg.enabled)
|
|
return [cv];
|
|
print("Debuggee died.");
|
|
} else if ('return' in cv) {
|
|
if (!dbg.enabled)
|
|
return [undefined];
|
|
showDebuggeeValue(cv.return);
|
|
} else {
|
|
if (!dbg.enabled)
|
|
return [cv];
|
|
print("Exception caught. (To rethrow it, type 'throw'.)");
|
|
lastExc = cv.throw;
|
|
showDebuggeeValue(lastExc);
|
|
}
|
|
}
|
|
}
|
|
|
|
function detachCommand() {
|
|
dbg.enabled = false;
|
|
return [undefined];
|
|
}
|
|
|
|
function continueCommand() {
|
|
if (focusedFrame === null) {
|
|
print("No stack.");
|
|
return;
|
|
}
|
|
return [undefined];
|
|
}
|
|
|
|
function throwCommand(rest) {
|
|
var v;
|
|
if (focusedFrame !== topFrame) {
|
|
print("To throw, you must select the newest frame (use 'frame 0').");
|
|
return;
|
|
} else if (focusedFrame === null) {
|
|
print("No stack.");
|
|
return;
|
|
} else if (rest === '') {
|
|
return [{throw: lastExc}];
|
|
} else {
|
|
var cv = saveExcursion(function () { return focusedFrame.eval(rest); });
|
|
if (cv === null) {
|
|
if (!dbg.enabled)
|
|
return [cv];
|
|
print("Debuggee died while determining what to throw. Stopped.");
|
|
} else if ('return' in cv) {
|
|
return [{throw: cv.return}];
|
|
} else {
|
|
if (!dbg.enabled)
|
|
return [cv];
|
|
print("Exception determining what to throw. Stopped.");
|
|
showDebuggeeValue(cv.throw);
|
|
}
|
|
return;
|
|
}
|
|
}
|
|
|
|
function frameCommand(rest) {
|
|
var n, f;
|
|
if (rest.match(/[0-9]+/)) {
|
|
n = +rest;
|
|
f = topFrame;
|
|
if (f === null) {
|
|
print("No stack.");
|
|
return;
|
|
}
|
|
for (var i = 0; i < n && f; i++) {
|
|
if (!f.older) {
|
|
print("There is no frame " + rest + ".");
|
|
return;
|
|
}
|
|
f.older.younger = f;
|
|
f = f.older;
|
|
}
|
|
focusedFrame = f;
|
|
showFrame(f, n);
|
|
} else if (rest !== '') {
|
|
if (topFrame === null)
|
|
print("No stack.");
|
|
else
|
|
showFrame();
|
|
} else {
|
|
print("do what now?");
|
|
}
|
|
}
|
|
|
|
function debugmeCommand() {
|
|
var meta = newGlobal("new-compartment");
|
|
meta.debuggeeGlobal = this;
|
|
meta.debuggerSource = debuggerSource;
|
|
meta.prompt = prompt.replace('(', '(meta-');
|
|
meta.eval(debuggerSource);
|
|
}
|
|
|
|
function upCommand() {
|
|
if (focusedFrame === null)
|
|
print("No stack.");
|
|
else if (focusedFrame.older === null)
|
|
print("Initial frame selected; you cannot go up.");
|
|
else {
|
|
focusedFrame.older.younger = focusedFrame;
|
|
focusedFrame = focusedFrame.older;
|
|
showFrame();
|
|
}
|
|
}
|
|
|
|
function downCommand() {
|
|
if (focusedFrame === null)
|
|
print("No stack.");
|
|
else if (!focusedFrame.younger)
|
|
print("Youngest frame selected; you cannot go down.");
|
|
else {
|
|
focusedFrame = focusedFrame.younger;
|
|
showFrame();
|
|
}
|
|
}
|
|
|
|
function forcereturnCommand(rest) {
|
|
var v;
|
|
var f = focusedFrame;
|
|
if (f !== topFrame) {
|
|
print("To forcereturn, you must select the newest frame (use 'frame 0').");
|
|
} else if (f === null) {
|
|
print("Nothing on the stack.");
|
|
} else if (rest === '') {
|
|
return [{return: undefined}];
|
|
} else {
|
|
var cv = saveExcursion(function () { return f.eval(rest); });
|
|
if (cv === null) {
|
|
if (!dbg.enabled)
|
|
return [cv];
|
|
print("Debuggee died while determining what to forcereturn. Stopped.");
|
|
} else if ('return' in cv) {
|
|
return [{return: cv.return}];
|
|
} else {
|
|
if (!dbg.enabled)
|
|
return [cv];
|
|
print("Error determining what to forcereturn. Stopped.");
|
|
showDebuggeeValue(cv.throw);
|
|
}
|
|
}
|
|
}
|
|
|
|
// Build the table of commands.
|
|
var commands = {};
|
|
var commandArray = [
|
|
backtraceCommand, "bt", "where",
|
|
continueCommand, "c",
|
|
detachCommand,
|
|
debugmeCommand,
|
|
downCommand, "d",
|
|
forcereturnCommand,
|
|
frameCommand, "f",
|
|
printCommand, "p",
|
|
quitCommand, "q",
|
|
throwCommand, "t",
|
|
upCommand, "u"
|
|
];
|
|
var last = null;
|
|
for (var i = 0; i < commandArray.length; i++) {
|
|
var cmd = commandArray[i];
|
|
if (typeof cmd === "string")
|
|
commands[cmd] = last;
|
|
else
|
|
last = commands[cmd.name.replace(/Command$/, '')] = cmd;
|
|
}
|
|
|
|
// Break cmd into two parts: its first word and everything else.
|
|
function breakcmd(cmd) {
|
|
cmd = cmd.trimLeft();
|
|
var m = /\s/.exec(cmd);
|
|
if (m === null)
|
|
return [cmd, ''];
|
|
return [cmd.slice(0, m.index), cmd.slice(m.index).trimLeft()];
|
|
}
|
|
|
|
function runcmd(cmd) {
|
|
var pieces = breakcmd(cmd);
|
|
if (pieces[0] === "")
|
|
return undefined;
|
|
|
|
var first = pieces[0], rest = pieces[1];
|
|
if (!commands.hasOwnProperty(first)) {
|
|
print("unrecognized command '" + first + "'");
|
|
return undefined;
|
|
}
|
|
|
|
var cmd = commands[first];
|
|
if (cmd.length === 0 && rest !== '') {
|
|
print("this command cannot take an argument");
|
|
return undefined;
|
|
}
|
|
|
|
return cmd(rest);
|
|
}
|
|
|
|
function repl() {
|
|
var cmd;
|
|
for (;;) {
|
|
print("\n" + prompt);
|
|
cmd = readline();
|
|
if (cmd === null)
|
|
break;
|
|
|
|
try {
|
|
var result = runcmd(cmd);
|
|
if (result === undefined)
|
|
; // do nothing
|
|
else if (Array.isArray(result))
|
|
return result[0];
|
|
else
|
|
throw new Error("Internal error: result of runcmd wasn't array or undefined");
|
|
} catch (exc) {
|
|
print("*** Internal error: exception in the debugger code.");
|
|
print(" " + exc);
|
|
var me = prompt.replace(/^\((.*)\)$/, function (a, b) { return b; });
|
|
print("Debug " + me + "? (y/n)");
|
|
if (readline().match(/^\s*y/i) !== null)
|
|
debugMe();
|
|
else
|
|
print("ok, ignoring error");
|
|
}
|
|
}
|
|
}
|
|
|
|
var dbg = new Debugger(debuggeeGlobal);
|
|
dbg.onDebuggerStatement = function (frame) {
|
|
return saveExcursion(function () {
|
|
topFrame = focusedFrame = frame;
|
|
print("'debugger' statement hit.");
|
|
showFrame();
|
|
return repl();
|
|
});
|
|
};
|
|
dbg.onThrow = function (frame, exc) {
|
|
return saveExcursion(function () {
|
|
topFrame = focusedFrame = frame;
|
|
print("Unwinding due to exception. (Type 'c' to continue unwinding.)");
|
|
showFrame();
|
|
print("Exception value is:");
|
|
showDebuggeeValue(exc);
|
|
return repl();
|
|
});
|
|
};
|
|
repl();
|
|
} + ")();"
|
|
|
|
print("jorendb version -0.0");
|
|
var g = newGlobal("new-compartment");
|
|
g.debuggeeGlobal = this;
|
|
g.prompt = '(jorendb)';
|
|
g.debuggerSource = debuggerSource;
|
|
g.eval(debuggerSource);
|
|
})();
|