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Joshua Gross
a715c5eba7
Summary: MountingManager keeps a map of tags to Views, and attempts to clean it up by (1) deleting tags when they're explicitly deleted, (2) recursively deleting all Views when the View hierarchy is torn down. However, there appear to be.... substantial gaps here. In tests, when navigating between screen X -> screen Y -> back to X (triggering a StopSurface), each "StopSurface" resulted in 200-600 Views being leaked (!). What is causing these leaks? Well, for one, the "dropView" mechanism isn't perfect, so it might be missed Views. Second, Views don't always guarantee that `reactTag == getId()`, so that could result in leaks. Third, View preallocation on Android complicates things: Views can be preallocated and then never even inserted into the View hierarchy, so DELETE mutations could never be issued. Fourth, StopSurface is also complicated on Android (largely because of View preallocatioAndroid (largely because of View preallocation). So, I introduce a new mechanism: keep a list of all tags for a surface, and remove all tags for a surface when the surface is torn down. This should be fool-proof: it handles preallocation and normal creation; it can handle deletes; and we're guaranteed that tags cannot be added after a surface is stopped. Is this overly complicating things? Well, hopefully we can simplify all of this in the longterm. But until we get rid of View Preallocation, it seems like we need this mechanism - and View Preallocation might be around for a while, or forever. Other thoughts: it's possible that using other data-structures could be more efficient, but I'm guessing the perf implications here are marginal (compared to the insane amount of memory leaks we're fixing). It could also simplify things to have a SurfaceMountingManager interface that implies all actions happen on a specific surface, including teardown. Changelog: [Internal] Reviewed By: mdvacca Differential Revision: D25985409 fbshipit-source-id: f55b533770b1630c6c2a9b7a694d953aa3324428
Building React Native for Android
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