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225158d Explain when Debugger.Object instances are not unique per Debugger. Note that environment actors' 'binding' and 'assign' requests can elicit 'threadWouldRun' errors.
(0bb3b79 In Debugger.Environment, change setVariable not to create new bindings. Add deleteVariable.) |
(225158d Explain when Debugger.Object instances are not unique per Debugger. Note that environment actors' 'binding' and 'assign' requests can elicit 'threadWouldRun' errors.) |
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SpiderMonkey creates exactly one <code>Debugger.Object</code> instance for each debuggee object it presents to a given <code>Debugger</code> instance: if the debugger encounters the same object through two different routes (perhaps two functions are called on the same object), SpiderMonkey presents the same <code>Debugger.Object</code> instance to the debugger each time. This means that the debugger can use the <code>==</code> operator to recognize when two <code>Debugger.Object</code> instances refer to the same debuggee object, and place its own properties on a <code>Debugger.Object</code> instance to store metadata about particular debuggee objects. | SpiderMonkey creates exactly one <code>Debugger.Object</code> instance for each debuggee object it presents to a given <code>Debugger</code> instance: if the debugger encounters the same object through two different routes (perhaps two functions are called on the same object), SpiderMonkey presents the same <code>Debugger.Object</code> instance to the debugger each time. This means that the debugger can use the <code>==</code> operator to recognize when two <code>Debugger.Object</code> instances refer to the same debuggee object, and place its own properties on a <code>Debugger.Object</code> instance to store metadata about particular debuggee objects. | ||
(If more than one <code>Debugger</code> instance is debugging the same code, each <code>Debugger</code> gets a separate <code>Debugger.Object</code> instance for a given object. This allows the code using each <code>Debugger</code> instance to place whatever properties it likes on its own <code>Debugger.Object</code> instances, without worrying about interfering with other debuggers. | JavaScript code in different compartments can have different views of the same object. For example, in Firefox, code in privileged compartments sees content DOM element objects without redefinitions or extensions made to that object's properties by content code. (In Firefox terminology, privileged code sees the element through an "xray wrapper".) To ensure that debugger code sees each object just as the debuggee would, each <code>Debugger.Object</code> instance presents its referent as it would be seen from a particular compartment. This "viewing compartment" is chosen to match the way the debugger came across the referent. As a consequence, a single <code>Debugger</code> instance may actually have several <code>Debugger.Object</code> instances: one for each compartment from which the referent is viewed. | ||
If more than one <code>Debugger</code> instance is debugging the same code, each <code>Debugger</code> gets a separate <code>Debugger.Object</code> instance for a given object. This allows the code using each <code>Debugger</code> instance to place whatever properties it likes on its own <code>Debugger.Object</code> instances, without worrying about interfering with other debuggers. | |||
While most <code>Debugger.Object</code> instances are created by SpiderMonkey in the process of exposing debuggee's behavior and state to the debugger, the debugger can use <code>Debugger.Object.prototype.makeDebuggeeValue</code> to create <code>Debugger.Object</code> instances for given debuggee objects, or use <code>Debugger.Object.prototype.copy</code> and <code>Debugger.Object.prototype.create</code> to create new objects in debuggee compartments, allocated as if by particular debuggee globals. | While most <code>Debugger.Object</code> instances are created by SpiderMonkey in the process of exposing debuggee's behavior and state to the debugger, the debugger can use <code>Debugger.Object.prototype.makeDebuggeeValue</code> to create <code>Debugger.Object</code> instances for given debuggee objects, or use <code>Debugger.Object.prototype.copy</code> and <code>Debugger.Object.prototype.create</code> to create new objects in debuggee compartments, allocated as if by particular debuggee globals. | ||
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Note that, if <i>value</i> is an object, it need not be one allocated in a debuggee global, nor even a debuggee compartment; it can be any object the debugger wishes to use as a debuggee value. | Note that, if <i>value</i> is an object, it need not be one allocated in a debuggee global, nor even a debuggee compartment; it can be any object the debugger wishes to use as a debuggee value. | ||
As [[#Debugger_Object|described above]], each <code>Debugger.Object</code> instance presents its referent as viewed from a particular compartment. Given a <code>Debugger.Object</code> instance <i>d</i> and an object <i>o</i>, the call <code><i>d</i>.makeDebuggeeValue(<i>o</i>)</code> returns a <code>Debugger.Object</code> instance that presents <i>o</i> as it would be seen by code in <i>d</i>'s compartment. | |||
<dt>decompile([<i>pretty</i>]) | <dt>decompile([<i>pretty</i>]) | ||