1186779 - Make const_casts with AllocateAudioBlock() safer

Status: RESOLVED FIXED

(Core :: Web Audio, defect)

Description

[Karl Tomlinson (:karlt)]

+++ This bug was initially created as a clone of Bug #1184801 +++

AllocateAudioBlock() expects const_cast to be used to write data for its new
chunk.

Comment 1

[Karl Tomlinson (:karlt)]

Attachment: add a method to cast AudioChunk data for writing when not shared

I first looked into returning float[WEBAUDIO_BLOCK_SIZE]* from
AllocateAudioBlock in order to provide compile-time constraints on usage.
That's probably possible, but would lose the feature of having all buffer
info on the AudioChunk, so requires handling the buffers through two different
objects and loses some run time channel count checking.  It would also require
a re-org in code like AudioBufferSourceNode, which makes late decisions on
allocation.

This approach is simple, keeps everything in one place, and provides run-time
checking.

Comment 2

[Karl Tomlinson (:karlt)]

Attachment: use ChannelFloatsForWrite() instead of const_cast

Comment 3

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/eb35e2460913
https://hg.mozilla.org/integration/mozilla-inbound/rev/44b77af83570

Comment 4

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/eb35e2460913
https://hg.mozilla.org/mozilla-central/rev/44b77af83570