README.txt
author Andrew McCreight <continuation@gmail.com>
Mon, 22 Apr 2019 16:34:51 +0000
changeset 470376 3073770e06f157040f4c64951b7e8425e1ad7bbe
parent 442551 480b34db3172d2456b619681d4a05216221066f0
permissions -rw-r--r--
Bug 1535403 - Take indirection into account for the CC optimizations for the outer window wrapper. r=peterv Most wrapper cached C++ objects are held alive by their wrapper. The cycle collector takes advantage of this in many classes and ignores the C++ object if the wrapper is marked black. However, this is not true for the outer window's wrapper. Instead, the outer window's wrapper keeps the inner window alive. The inner window usually keeps its outer window alive, but not after it has been unlinked. For reasons I do not yet understand, the outer window's wrapper can be kept alive after the inner window it is a proxy for is unlinked. This patch fixes the cycle collector optimization for the outer window by only applying it if the outer window still has a weak reference to the inner window, which it will until the inner no longer holds the outer alive. This in turn fixes, or at least helps fix, window leaks seen intermittently when the lifetime of outer windows and docshells are tied together. The code comment is based on a review comment by peterv. Differential Revision: https://phabricator.services.mozilla.com/D27981

An explanation of the Mozilla Source Code Directory Structure and links to
project pages with documentation can be found at:

    https://developer.mozilla.org/en/Mozilla_Source_Code_Directory_Structure

For information on how to build Mozilla from the source code, see:

    https://developer.mozilla.org/en/docs/Build_Documentation

To have your bug fix / feature added to Mozilla, you should create a patch and
submit it to Bugzilla (https://bugzilla.mozilla.org). Instructions are at:

    https://developer.mozilla.org/en/docs/Creating_a_patch
    https://developer.mozilla.org/en/docs/Getting_your_patch_in_the_tree

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Keep in mind that nightly builds, which are used by Mozilla developers for
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