Expose vips internal cache settings and status

README.md

@@ -51,7 +51,7 @@ Scale and crop to `width` x `height` calling `callback` when complete.
 
 `callback` gets two arguments `(err, buffer)` where `err` is an error message, if any, and `buffer` is the resultant image data when a Buffer is requested.
 
-### Examples
+#### Examples
 
 ```javascript
 sharp.resize("input.jpg", "output.jpg", 300, 200, function(err) {
@@ -101,6 +101,20 @@ sharp.resize("input.jpg", sharp.buffer.webp, 200, 300, {canvas: sharp.canvas.emb
 });
 ```
 
+### cache([limit])
+
+If `limit` is provided, set the `vips` internal cache limit to this value in MB. The default value is 100.
+
+Always returns cache statistics, namely current usage, high water mark and maximum limit.
+
+The high water mark may be higher than the maximum limit.
+
+```javascript
+var stats = sharp.cache(); // { current: 98, high: 115, limit: 100 }
+sharp.cache(200); // { current: 98, high: 115, limit: 200 }
+sharp.cache(50); // { current: 49, high: 115, limit: 50 }
+```
+
 ## Testing
 
 	npm test

index.js

@@ -53,6 +53,13 @@ module.exports.resize = function(input, output, width, height, options, callback
   sharp.resize(options.inFile, options.inBuffer, output, width, height, canvas, sharpen, progessive, sequentialRead, callback);
 };
 
+module.exports.cache = function(limit) {
+  if (Number.isNaN(limit)) {
+    limit = null;
+  }
+  return sharp.cache(limit);
+}
+
 /* Deprecated v0.0.x methods */
 module.exports.crop = function(input, output, width, height, sharpen, callback) {
   sharp.resize(input, output, width, height, {canvas: "c", sharpen: true}, callback);

package.json

@@ -1,6 +1,6 @@
 {
   "name": "sharp",
-  "version": "0.1.6",
+  "version": "0.1.7",
   "author": "Lovell Fuller",
   "description": "High performance module to resize JPEG, PNG, WebP and TIFF images using the libvips image processing library",
   "scripts": {

src/sharp.cc

@@ -323,6 +323,22 @@ Handle<Value> resize(const Arguments& args) {
   return scope.Close(Undefined());
 }
 
+Handle<Value> cache(const Arguments& args) {
+  HandleScope scope;
+  
+  // Set cache limit
+  if (args[0]->IsInt32()) {
+    vips_cache_set_max_mem(args[0]->Int32Value() * 1048576);
+  }
+
+  // Get cache statistics
+  Local<Object> cache = Object::New();
+  cache->Set(String::NewSymbol("current"), Number::New(vips_tracked_get_mem() / 1048576));
+  cache->Set(String::NewSymbol("high"), Number::New(vips_tracked_get_mem_highwater() / 1048576));
+  cache->Set(String::NewSymbol("limit"), Number::New(vips_cache_get_max_mem() / 1048576));
+  return scope.Close(cache);
+}
+
 static void at_exit(void* arg) {
   HandleScope scope;
   vips_shutdown();
@@ -333,6 +349,7 @@ extern "C" void init(Handle<Object> target) {
   vips_init("");
   AtExit(at_exit);
   NODE_SET_METHOD(target, "resize", resize);
+  NODE_SET_METHOD(target, "cache", cache);
 }
 
 NODE_MODULE(sharp, init)

tests/parallel.js

@@ -26,4 +26,6 @@ async.mapSeries([1, 1, 2, 4, 8, 16, 32, 64, 128], function(parallelism, next) {
       next();
     }
   );
-}, function() {});
+}, function() {
+  console.dir(sharp.cache());
+});

tests/perf.js

@@ -420,4 +420,5 @@ async.series({
   Object.keys(results).forEach(function(format) {
     assert.strictEqual("sharp", results[format].toString().substr(0, 5), "sharp was slower than " + results[format] + " for " + format);
   });
+  console.dir(sharp.cache());
 });