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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 09:22:09 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 09:22:09 +0000 |
commit | 43a97878ce14b72f0981164f87f2e35e14151312 (patch) | |
tree | 620249daf56c0258faa40cbdcf9cfba06de2a846 /devtools/shared/test-helpers/thread-helpers.sys.mjs | |
parent | Initial commit. (diff) | |
download | firefox-upstream.tar.xz firefox-upstream.zip |
Adding upstream version 110.0.1.upstream/110.0.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | devtools/shared/test-helpers/thread-helpers.sys.mjs | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/devtools/shared/test-helpers/thread-helpers.sys.mjs b/devtools/shared/test-helpers/thread-helpers.sys.mjs new file mode 100644 index 0000000000..9e28f87a35 --- /dev/null +++ b/devtools/shared/test-helpers/thread-helpers.sys.mjs @@ -0,0 +1,141 @@ +/* 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/. */ + +/** + * Helper code to play with the javascript thread + **/ + +function getSandboxWithDebuggerSymbol() { + const { addDebuggerToGlobal } = ChromeUtils.import( + "resource://gre/modules/jsdebugger.jsm" + ); + const systemPrincipal = Services.scriptSecurityManager.getSystemPrincipal(); + + const debuggerSandbox = Cu.Sandbox(systemPrincipal, { + // This sandbox is also reused for ChromeDebugger implementation. + // As we want to load the `Debugger` API for debugging chrome contexts, + // we have to ensure loading it in a distinct compartment from its debuggee. + freshCompartment: true, + invisibleToDebugger: true, + }); + addDebuggerToGlobal(debuggerSandbox); + + return debuggerSandbox; +} + +/** + * Implementation of a Javascript tracer logging traces to stdout. + * + * To be used like this: + + const { traceAllJSCalls } = ChromeUtils.importESModule( + "resource://devtools/shared/test-helpers/thread-helpers.sys.mjs" + ); + const jsTracer = traceAllJSCalls(); + [... execute some code to tracer ...] + jsTracer.stop(); + + * @param prefix String + * Optional, if passed, this will be displayed in front of each + * line reporting a new frame execution. + * @param pause Number + * Optional, if passed, hold off each frame for `pause` ms, + * by letting the other event loops run in between. + * Be careful that it can introduce unexpected race conditions + * that can't necessarily be reproduced without this. + */ +export function traceAllJSCalls({ prefix = "", pause } = {}) { + const debuggerSandbox = getSandboxWithDebuggerSymbol(); + + debuggerSandbox.Services = Services; + const f = Cu.evalInSandbox( + "(" + + function(pauseInMs, prefixString) { + const dbg = new Debugger(); + // Add absolutely all the globals... + dbg.addAllGlobalsAsDebuggees(); + // ...but avoid tracing this sandbox code + const global = Cu.getGlobalForObject(this); + dbg.removeDebuggee(global); + + // Add all globals created later on + dbg.onNewGlobalObject = g => dbg.addDebuggee(g); + + function formatDisplayName(frame) { + if (frame.type === "call") { + const callee = frame.callee; + return callee.name || callee.userDisplayName || callee.displayName; + } + + return `(${frame.type})`; + } + + function stop() { + dbg.onEnterFrame = undefined; + dbg.removeAllDebuggees(); + } + global.stop = stop; + + let depth = 0; + dbg.onEnterFrame = frame => { + if (depth == 100) { + dump( + "Looks like an infinite loop? We stop the js tracer, but code may still be running!\n" + ); + stop(); + return; + } + + const { script } = frame; + const { lineNumber, columnNumber } = script.getOffsetMetadata( + frame.offset + ); + const padding = new Array(depth).join(" "); + dump( + `${prefixString}${padding}--[${frame.implementation}]--> ${ + script.source.url + } @ ${lineNumber}:${columnNumber} - ${formatDisplayName(frame)}\n` + ); + + depth++; + frame.onPop = () => { + depth--; + }; + + // Optionaly pause the frame execute by letting the other event loop to run in between. + if (typeof pauseInMs == "number") { + let freeze = true; + const timer = Cc["@mozilla.org/timer;1"].createInstance( + Ci.nsITimer + ); + timer.initWithCallback( + () => { + freeze = false; + }, + pauseInMs, + Ci.nsITimer.TYPE_ONE_SHOT + ); + Services.tm.spinEventLoopUntil("debugger-slow-motion", function() { + return !freeze; + }); + } + }; + + return { stop }; + } + + ")", + debuggerSandbox, + undefined, + "debugger-javascript-tracer", + 1, + /* enforceFilenameRestrictions */ false + ); + f(pause, prefix); + + return { + stop() { + debuggerSandbox.stop(); + }, + }; +} |