stdlib: Make non-native ArrayBuffer.capacity smaller

meg-gupta · meg-gupta · commit a461a48862af · 2020-05-18T13:17:57.000-07:00
Similar to swiftlang#28486 in motivation. Before this change 'count' got lowered to multiple 'endIndex' calls Fixes rdar://46702232
diff --git a/stdlib/public/core/ArrayBuffer.swift b/stdlib/public/core/ArrayBuffer.swift
@@ -315,7 +315,7 @@ extension _ArrayBuffer {
   /// The number of elements the buffer can store without reallocation.
   @inlinable
   internal var capacity: Int {
-    return _fastPath(_isNative) ? _native.capacity : _nonNative.count
+    return _fastPath(_isNative) ? _native.capacity : _nonNative.endIndex
   }
 
   @inlinable

Original file line number	Diff line number	Diff line change
`@@ -315,7 +315,7 @@ extension _ArrayBuffer {`
`315`	`315`	`/// The number of elements the buffer can store without reallocation.`
`316`	`316`	`@inlinable`
`317`	`317`	`internal var capacity: Int {`
`318`		`- return _fastPath(_isNative) ? _native.capacity : _nonNative.count`
	`318`	`+ return _fastPath(_isNative) ? _native.capacity : _nonNative.endIndex`
`319`	`319`	`}`
`320`	`320`
`321`	`321`	`@inlinable`