src: add fast path for equal size to Reallocate()

addaleax · targos · commit 26361d1a5fb0 · 2019-03-27T22:16:12.000+01:00
When old and new size match, we can skip the rest of the function, which makes sense in the case of embedders who do not use Node's allocator, as that would lead to needlessly allocating and freeing buffers of identical sizes. PR-URL: #26573 Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Richard Lau <riclau@uk.ibm.com> Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de> Reviewed-By: James M Snell <jasnell@gmail.com>
diff --git a/src/env.cc b/src/env.cc
@@ -959,6 +959,7 @@ void Environment::BuildEmbedderGraph(Isolate* isolate,
 }
 
 char* Environment::Reallocate(char* data, size_t old_size, size_t size) {
+  if (old_size == size) return data;
   // If we know that the allocator is our ArrayBufferAllocator, we can let
   // if reallocate directly.
   if (isolate_data()->uses_node_allocator()) {

Original file line number	Diff line number	Diff line change
`@@ -959,6 +959,7 @@ void Environment::BuildEmbedderGraph(Isolate* isolate,`
`959`	`959`	`}`
`960`	`960`
`961`	`961`	`char* Environment::Reallocate(char* data, size_t old_size, size_t size) {`
	`962`	`+ if (old_size == size) return data;`
`962`	`963`	`// If we know that the allocator is our ArrayBufferAllocator, we can let`
`963`	`964`	`// if reallocate directly.`
`964`	`965`	`if (isolate_data()->uses_node_allocator()) {`