Add timeout function to limit processing time

lib/output.js

@@ -975,6 +975,31 @@ function tile (options) {
   return this._updateFormatOut('dz');
 }
 
+/**
+ * Set a timeout for processing, in seconds.
+ * Use a value of zero to continue processing indefinitely, the default behaviour.
+ *
+ * The clock starts when libvips opens an input image for processing.
+ * Time spent waiting for a libuv thread to become available is not included.
+ *
+ * @since 0.29.2
+ *
+ * @param {Object} options
+ * @param {number} options.seconds - Number of seconds after which processing will be stopped
+ * @returns {Sharp}
+ */
+function timeout (options) {
+  if (!is.plainObject(options)) {
+    throw is.invalidParameterError('options', 'object', options);
+  }
+  if (is.integer(options.seconds) && is.inRange(options.seconds, 0, 3600)) {
+    this.options.timeoutSeconds = options.seconds;
+  } else {
+    throw is.invalidParameterError('seconds', 'integer between 0 and 3600', options.seconds);
+  }
+  return this;
+}
+
 /**
  * Update the output format unless options.force is false,
  * in which case revert to input format.
@@ -1129,6 +1154,7 @@ module.exports = function (Sharp) {
     gif,
     raw,
     tile,
+    timeout,
     // Private
     _updateFormatOut,
     _setBooleanOption,