Web Inspector: Heap: don't use recursion when calculating root paths

[Devin Rousso]

If a path is extremely deep, it can cause a stack overflow.

[Radar WebKit Bug Importer]

<rdar://problem/49870751>

[Devin Rousso]

Created attachment 367366 [details]
Patch

[Joseph Pecoraro]

Comment on attachment 367366 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=367366&action=review

r=me

> Source/WebInspectorUI/UserInterface/Workers/HeapSnapshot/HeapSnapshot.js:756
> +        for (let i = 0; i < stack.length; ++i) {
> +            let {currentPath, nodeOrdinal} = stack[i];

This list is not being treated as a stack. In fact it is always growing because nothing nothing is ever removed.

Normally when we have a stack approach like this we process it to exhaustion like this:

    let stack = [{...entry...}];
    while (stack.length) {
        let entry = stack.pop();
        // Process entry, maybe push new stack entries.
    }

Which I think could be done here as long as you convert these two lines to:

    while (stack.length) {
        let {currentPath, nodeOridinal} = stack.pop();
        ...

That said, items are going to be processes on the stack in reverse order... so to get unchanging output you could iterate the edges in forward order such as:

    while (stack.length) {
        let {currentPath, nodeOridinal} = stack.unshift();
        ...

That should get you output that is consistent with the current code.

[Devin Rousso]

Created attachment 367460 [details]
Patch

[WebKit Commit Bot]

Comment on attachment 367460 [details]
Patch

Clearing flags on attachment: 367460

Committed r244308: <https://trac.webkit.org/changeset/244308>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.