Remove unnecessary string and string[] allocations from MS.Internal.ContentType#6268
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dipeshmsft merged 3 commits intodotnet:mainfrom May 5, 2022
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The parsing logic involves a loop that repeatedly Substrings and Trims the remaining space. We can change this to use spans and only create strings when they're actually needed to be stored; the other temporary slices don't need to allocate.
danmoseley
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Mar 18, 2022
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| int startingLength = ++length; | ||
| length = s.Slice(startingLength).IndexOf('"'); |
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| int startingLength = ++length; | |
| length = s.Slice(startingLength).IndexOf('"'); | |
| int startingLength = length + 1; | |
| length = s.Slice(startingLength).IndexOf('"') + 1; |
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That won't work correctly. We can change the ++length to be length + 1, but not the second line.
danmoseley
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Mar 18, 2022
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Description
MS.Internal.ContentType is incurring a multitude of unnecessary allocations. It's parsing input by Substring'ing along it and Trim'ing along it to find the next piece, but only a subset of those strings are actually saved. It's using string.Split just to get two strings, resulting in a string[]. Etc.
Customer Impact
Apps using this indirectly incur unnecessary overhead.
Regression
No
Testing
CI
Risk
Minimal.