560378 - Fix MSVC warnings in nsCanvasRenderingContext2D.cpp

Status: RESOLVED FIXED

(Core :: Graphics: Canvas2D, defect)

Description

[Daniel Holbert [:dholbert]]

Found these warnings when building with WARNINGS_AS_ERRORS in content/canvas/src/
> nsCanvasRenderingContext2D.cpp(123) : error C2220: warning treated as error - no 'object' file generated
> nsCanvasRenderingContext2D.cpp(123) : warning C4800: 'int' : forcing value to bool 'true' or 'false' (performance warning)
> nsCanvasRenderingContext2D.cpp(715) : warning C4156: deletion of an array expression without using the array form of 'delete'; array form substituted
> nsCanvasRenderingContext2D.cpp(716) : warning C4156: deletion of an array expression without using the array form of 'delete'; array form substituted
> nsCanvasRenderingContext2D.cpp(2067) : warning C4244: 'argument' : conversion from 'const PRUint32' to 'float', possible loss of data
> nsCanvasRenderingContext2D.cpp(3330) : warning C4244: 'argument' : conversion from 'float' to 'PRInt32', possible loss of data
> nsCanvasRenderingContext2D.cpp(3330) : warning C4244: 'argument' : conversion from 'float' to 'PRInt32', possible loss of data
http://tinderbox.mozilla.org/showlog.cgi?log=MozillaTry/1271714234.1271717009.25882.gz

The warnings at lines 715-716 are actually kind of scary -- IIRC, mismatched new[]/delete operators can cause memory corruption. (though in this case the compiler is saving us, as the warning indicates)

Patches coming up.

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: Patch A: fix for "forcing value to bool"

Comment 2

[Daniel Holbert [:dholbert]]

Attachment: Patch B: Fix for "deletion of an array expression without using the array form of 'delete'"

Comment 3

[Daniel Holbert [:dholbert]]

Attachment: Patch C: Fix for float/int conversion warnings

This patch just adds explicit int<-->float casts where the compiler is already warning us about automatic casts that it's doing.

Comment 4

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

Comment on attachment 440067 [details] [diff] [review]
Patch C: Fix for float/int conversion warnings

all look good, thanks!

Comment 5

[Daniel Holbert [:dholbert]]

http://hg.mozilla.org/mozilla-central/rev/242f5193b74d
http://hg.mozilla.org/mozilla-central/rev/82e28ff353c6
http://hg.mozilla.org/mozilla-central/rev/3de42a92615f