JS_SetInterruptCallback 编辑

This article covers features introduced in SpiderMonkey 31

Set a callback function that is automatically called periodically while JavaScript code runs.

Syntax

JSInterruptCallback
JS_SetInterruptCallback(JSRuntime *rt, JSInterruptCallback callback);

JSInterruptCallback
JS_GetInterruptCallback(JSRuntime *rt);

void
JS_RequestInterruptCallback(JSRuntime *rt);

Callback syntax

bool
(* JSInterruptCallback)(JSContext *cx);

Description

These functions allow setting an interrupt callback that will be called from the JS thread some time after any thread triggered the callback using JS_RequestInterruptCallback.
To schedule the GC and for other activities the engine internally triggers interrupt callbacks. The embedding should thus not rely on callbacks being triggered through the external API only.

Important note: Additional callbacks can occur inside the callback handler if it re-enters the JS engine. The embedding must ensure that the callback is disconnected before attempting such re-entry.

JS_SetInterruptCallback sets a callback that can be called asynchronously. Some common uses for an interrupt callback are:

• To run garbage collection periodically, by calling JS_MaybeGC;
• To periodically take a break from script execution to update the UI (though note that Mozilla does not do this, by design);
• To enforce application limits on the amount of time a script may run. (In this case, the callback may terminate the script by returning false.)

JS_GetInterruptCallback returns the currently installed interrupt callback, or NULL if none is currently installed.

JS_RequestInterruptCallback requests a callback set using JS_SetInterruptCallback.

See Also

• MXR ID Search for JS_SetInterruptCallback
• MXR ID Search for JS_GetInterruptCallback
• MXR ID Search for JS_RequestInterruptCallback
• bug 977287