Optimization: Reuse ArrayBuffer during serialization.

BUILD.gn

@@ -79,6 +79,7 @@ ts_sources = [
   "js/fetch.ts",
   "js/file_info.ts",
   "js/files.ts",
+  "js/flatbuffers.ts",
   "js/global_eval.ts",
   "js/globals.ts",
   "js/io.ts",

js/copy_file.ts

 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 import * as msg from "gen/msg_generated";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import * as dispatch from "./dispatch";
 
 /** Copies the contents of a file to another by name synchronously.
@@ -36,7 +36,7 @@ function req(
   from: string,
   to: string
 ): [flatbuffers.Builder, msg.Any, flatbuffers.Offset] {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const from_ = builder.createString(from);
   const to_ = builder.createString(to);
   msg.CopyFile.startCopyFile(builder);

js/dir.ts

 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 import * as msg from "gen/msg_generated";
 import { assert } from "./util";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import { sendSync } from "./dispatch";
 
 /**
@@ -12,7 +12,7 @@ import { sendSync } from "./dispatch";
  * throws NotFound exception if directory not available
  */
 export function cwd(): string {
-  const builder = new flatbuffers.Builder(0);
+  const builder = flatbuffers.createBuilder();
   msg.Cwd.startCwd(builder);
   const inner = msg.Cwd.endCwd(builder);
   const baseRes = sendSync(builder, msg.Any.Cwd, inner);
@@ -28,7 +28,7 @@ export function cwd(): string {
  * throws NotFound exception if directory not available
  */
 export function chdir(directory: string): void {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const directory_ = builder.createString(directory);
   msg.Chdir.startChdir(builder);
   msg.Chdir.addDirectory(builder, directory_);

js/dispatch.ts

 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 import { libdeno } from "./libdeno";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import * as msg from "gen/msg_generated";
 import * as errors from "./errors";
 import * as util from "./util";
@@ -86,6 +86,7 @@ function sendInternal(
   msg.Base.addSync(builder, sync);
   msg.Base.addCmdId(builder, cmdId);
   builder.finish(msg.Base.endBase(builder));
-
-  return [cmdId, libdeno.send(builder.asUint8Array(), data)];
+  const res = libdeno.send(builder.asUint8Array(), data);
+  builder.inUse = false;
+  return [cmdId, res];
 }

js/fetch.ts

@@ -7,7 +7,7 @@ import {
   typedArrayToArrayBuffer,
   notImplemented
 } from "./util";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import { sendAsync } from "./dispatch";
 import * as msg from "gen/msg_generated";
 import * as domTypes from "./dom_types";
@@ -187,7 +187,7 @@ export async function fetch(
   log("dispatch FETCH_REQ", url);
 
   // Send FetchReq message
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const url_ = builder.createString(url);
   msg.FetchReq.startFetchReq(builder);
   msg.FetchReq.addUrl(builder, url_);

js/files.ts

@@ -4,7 +4,7 @@ import { Reader, Writer, Closer, ReadResult } from "./io";
 import * as dispatch from "./dispatch";
 import * as msg from "gen/msg_generated";
 import { assert } from "./util";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 
 /** The Deno abstraction for reading and writing files. */
 export class File implements Reader, Writer, Closer {
@@ -51,7 +51,7 @@ export async function open(
   filename: string,
   mode: OpenMode = "r"
 ): Promise<File> {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const filename_ = builder.createString(filename);
   msg.Open.startOpen(builder);
   msg.Open.addFilename(builder, filename_);
@@ -73,7 +73,7 @@ export async function read(
   rid: number,
   p: ArrayBufferView
 ): Promise<ReadResult> {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   msg.Read.startRead(builder);
   msg.Read.addRid(builder, rid);
   const inner = msg.Read.endRead(builder);
@@ -90,7 +90,7 @@ export async function read(
  * Resolves with the number of bytes written.
  */
 export async function write(rid: number, p: ArrayBufferView): Promise<number> {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   msg.Write.startWrite(builder);
   msg.Write.addRid(builder, rid);
   const inner = msg.Write.endWrite(builder);
@@ -104,7 +104,7 @@ export async function write(rid: number, p: ArrayBufferView): Promise<number> {
 
 /** Close the file ID. */
 export function close(rid: number): void {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   msg.Close.startClose(builder);
   msg.Close.addRid(builder, rid);
   const inner = msg.Close.endClose(builder);

js/flatbuffers.ts

+// Copyright 2018 the Deno authors. All rights reserved. MIT license.
+
+import { flatbuffers } from "flatbuffers";
+import * as util from "./util";
+
+// Re-export some types.
+export type Offset = flatbuffers.Offset;
+export class ByteBuffer extends flatbuffers.ByteBuffer {}
+export interface Builder extends flatbuffers.Builder {
+  inUse: boolean;
+}
+
+const globalBuilder = new flatbuffers.Builder() as Builder;
+globalBuilder.inUse = false;
+
+// This is a wrapper around the real Builder .
+// The purpose is to reuse a single ArrayBuffer for every message.
+// We can do this because the "control" messages sent to the privileged
+// side are guarenteed to be used during the call to libdeno.send().
+export function createBuilder(): Builder {
+  // tslint:disable-next-line:no-any
+  const gb = globalBuilder as any;
+  util.assert(!gb.inUse);
+
+  let bb = globalBuilder.dataBuffer();
+  // Only create a new backing ArrayBuffer if the previous one had grown very
+  // large in capacity. This should only happen rarely.
+  if (bb.capacity() > 1024) {
+    util.log(`realloc flatbuffer ArrayBuffer because it was ${bb.capacity()}`);
+    bb = ByteBuffer.allocate(1024);
+  }
+  gb.bb = bb;
+  // Remaining space in the ByteBuffer.
+  gb.space = globalBuilder.dataBuffer().capacity();
+  // Minimum alignment encountered so far.
+  gb.minalign = 1;
+  // The vtable for the current table.
+  gb.vtable = null;
+  // The amount of fields we're actually using.
+  gb.vtable_in_use = 0;
+  // Whether we are currently serializing a table.
+  gb.isNested = false;
+  // Starting offset of the current struct/table.
+  gb.object_start = 0;
+  // List of offsets of all vtables.
+  gb.vtables = [];
+  // For the current vector being built.
+  gb.vector_num_elems = 0;
+  // False omits default values from the serialized data
+  gb.force_defaults = false;
+
+  gb.inUse = true;
+
+  return gb as Builder;
+}

js/main.ts

 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import * as msg from "gen/msg_generated";
 import { assert, log, setLogDebug } from "./util";
 import * as os from "./os";
@@ -11,7 +11,7 @@ import { promiseErrorExaminer, promiseRejectHandler } from "./promise_util";
 import { version } from "typescript";
 
 function sendStart(): msg.StartRes {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   msg.Start.startStart(builder);
   const startOffset = msg.Start.endStart(builder);
   const baseRes = sendSync(builder, msg.Any.Start, startOffset);

js/make_temp_dir.ts

 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 import * as msg from "gen/msg_generated";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import * as dispatch from "./dispatch";
 import { assert } from "./util";
 
@@ -43,7 +43,7 @@ function req({
   prefix,
   suffix
 }: MakeTempDirOptions): [flatbuffers.Builder, msg.Any, flatbuffers.Offset] {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const fbDir = dir == null ? -1 : builder.createString(dir);
   const fbPrefix = prefix == null ? -1 : builder.createString(prefix);
   const fbSuffix = suffix == null ? -1 : builder.createString(suffix);

js/metrics.ts

 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 import * as msg from "gen/msg_generated";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import { assert } from "./util";
 import * as dispatch from "./dispatch";
 
@@ -18,7 +18,7 @@ export function metrics(): Metrics {
 }
 
 function req(): [flatbuffers.Builder, msg.Any, flatbuffers.Offset] {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   msg.Metrics.startMetrics(builder);
   const inner = msg.Metrics.endMetrics(builder);
   return [builder, msg.Any.Metrics, inner];

js/mkdir.ts

 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 import * as msg from "gen/msg_generated";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import * as dispatch from "./dispatch";
 
 /** Creates a new directory with the specified path and permission
@@ -26,7 +26,7 @@ function req(
   path: string,
   mode: number
 ): [flatbuffers.Builder, msg.Any, flatbuffers.Offset] {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const path_ = builder.createString(path);
   msg.Mkdir.startMkdir(builder);
   msg.Mkdir.addPath(builder, path_);

js/net.ts

@@ -4,7 +4,7 @@ import { ReadResult, Reader, Writer, Closer } from "./io";
 import * as msg from "gen/msg_generated";
 import { assert, notImplemented } from "./util";
 import * as dispatch from "./dispatch";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import { read, write, close } from "./files";
 
 export type Network = "tcp";
@@ -32,7 +32,7 @@ class ListenerImpl implements Listener {
   constructor(readonly rid: number) {}
 
   async accept(): Promise<Conn> {
-    const builder = new flatbuffers.Builder();
+    const builder = flatbuffers.createBuilder();
     msg.Accept.startAccept(builder);
     msg.Accept.addRid(builder, this.rid);
     const inner = msg.Accept.endAccept(builder);
@@ -111,7 +111,7 @@ enum ShutdownMode {
 }
 
 function shutdown(rid: number, how: ShutdownMode) {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   msg.Shutdown.startShutdown(builder);
   msg.Shutdown.addRid(builder, rid);
   msg.Shutdown.addHow(builder, how);
@@ -136,7 +136,7 @@ function shutdown(rid: number, how: ShutdownMode) {
  * See `dial()` for a description of the network and address parameters.
  */
 export function listen(network: Network, address: string): Listener {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const network_ = builder.createString(network);
   const address_ = builder.createString(address);
   msg.Listen.startListen(builder);
@@ -179,7 +179,7 @@ export function listen(network: Network, address: string): Listener {
  *     dial("tcp", ":80")
  */
 export async function dial(network: Network, address: string): Promise<Conn> {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const network_ = builder.createString(network);
   const address_ = builder.createString(address);
   msg.Dial.startDial(builder);

js/os.ts

@@ -3,12 +3,12 @@ import { ModuleInfo } from "./types";
 import * as msg from "gen/msg_generated";
 import { assert } from "./util";
 import * as util from "./util";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import { sendSync } from "./dispatch";
 
 /** Exit the Deno process with optional exit code. */
 export function exit(exitCode = 0): never {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   msg.Exit.startExit(builder);
   msg.Exit.addCode(builder, exitCode);
   const inner = msg.Exit.endExit(builder);
@@ -23,7 +23,7 @@ export function codeFetch(
 ): ModuleInfo {
   util.log("os.ts codeFetch", moduleSpecifier, containingFile);
   // Send CodeFetch message
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const moduleSpecifier_ = builder.createString(moduleSpecifier);
   const containingFile_ = builder.createString(containingFile);
   msg.CodeFetch.startCodeFetch(builder);
@@ -53,7 +53,7 @@ export function codeCache(
   outputCode: string
 ): void {
   util.log("os.ts codeCache", filename, sourceCode, outputCode);
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const filename_ = builder.createString(filename);
   const sourceCode_ = builder.createString(sourceCode);
   const outputCode_ = builder.createString(outputCode);
@@ -84,7 +84,7 @@ function createEnv(_inner: msg.EnvironRes): { [index: string]: string } {
 }
 
 function setEnv(key: string, value: string): void {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const _key = builder.createString(key);
   const _value = builder.createString(value);
   msg.SetEnv.startSetEnv(builder);
@@ -113,7 +113,7 @@ export function env(): { [index: string]: string } {
     command: msg.Command.ENV,
   });
   */
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   msg.Environ.startEnviron(builder);
   const inner = msg.Environ.endEnviron(builder);
   const baseRes = sendSync(builder, msg.Any.Environ, inner)!;

js/read_dir.ts

 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 import * as msg from "gen/msg_generated";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import * as dispatch from "./dispatch";
 import { FileInfo, FileInfoImpl } from "./file_info";
 import { assert } from "./util";
@@ -25,7 +25,7 @@ export async function readDir(path: string): Promise<FileInfo[]> {
 }
 
 function req(path: string): [flatbuffers.Builder, msg.Any, flatbuffers.Offset] {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const path_ = builder.createString(path);
   msg.ReadDir.startReadDir(builder);
   msg.ReadDir.addPath(builder, path_);

js/read_file.ts

 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 import * as msg from "gen/msg_generated";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import { assert } from "./util";
 import * as dispatch from "./dispatch";
 
@@ -29,7 +29,7 @@ export async function readFile(filename: string): Promise<Uint8Array> {
 function req(
   filename: string
 ): [flatbuffers.Builder, msg.Any, flatbuffers.Offset] {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const filename_ = builder.createString(filename);
   msg.ReadFile.startReadFile(builder);
   msg.ReadFile.addFilename(builder, filename_);

js/read_link.ts

 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 import * as msg from "gen/msg_generated";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import { assert } from "./util";
 import * as dispatch from "./dispatch";
 
@@ -23,7 +23,7 @@ export async function readlink(name: string): Promise<string> {
 }
 
 function req(name: string): [flatbuffers.Builder, msg.Any, flatbuffers.Offset] {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const name_ = builder.createString(name);
   msg.Readlink.startReadlink(builder);
   msg.Readlink.addName(builder, name_);

js/remove.ts

 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 import * as msg from "gen/msg_generated";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import * as dispatch from "./dispatch";
 
 /** Removes the named file or (empty) directory synchronously. Would throw
@@ -47,7 +47,7 @@ function req(
   path: string,
   recursive: boolean
 ): [flatbuffers.Builder, msg.Any, flatbuffers.Offset] {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const path_ = builder.createString(path);
   msg.Remove.startRemove(builder);
   msg.Remove.addPath(builder, path_);

js/rename.ts

 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 import * as msg from "gen/msg_generated";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import * as dispatch from "./dispatch";
 
 /** Synchronously renames (moves) `oldpath` to `newpath`. If `newpath` already
@@ -30,7 +30,7 @@ function req(
   oldpath: string,
   newpath: string
 ): [flatbuffers.Builder, msg.Any, flatbuffers.Offset] {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const oldpath_ = builder.createString(oldpath);
   const newpath_ = builder.createString(newpath);
   msg.Rename.startRename(builder);

js/stat.ts

 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 import * as msg from "gen/msg_generated";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import * as dispatch from "./dispatch";
 import { assert } from "./util";
 import { FileInfo, FileInfoImpl } from "./file_info";
@@ -54,7 +54,7 @@ function req(
   filename: string,
   lstat: boolean
 ): [flatbuffers.Builder, msg.Any, flatbuffers.Offset] {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const filename_ = builder.createString(filename);
   msg.Stat.startStat(builder);
   msg.Stat.addFilename(builder, filename_);

js/symlink.ts

 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 import * as msg from "gen/msg_generated";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import * as dispatch from "./dispatch";
 import * as util from "./util";
 
@@ -43,7 +43,7 @@ function req(
   if (type) {
     return util.notImplemented();
   }
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const oldname_ = builder.createString(oldname);
   const newname_ = builder.createString(newname);
   msg.Symlink.startSymlink(builder);

js/timers.ts

 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 import { assert } from "./util";
 import * as msg from "gen/msg_generated";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import { sendSync, setFireTimersCallback } from "./dispatch";
 
 // Tell the dispatcher which function it should call to fire timers that are
@@ -51,7 +51,7 @@ function setGlobalTimeout(due: number | null, now: number) {
     assert(timeout >= 0);
   }
   // Send message to the backend.
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   msg.SetTimeout.startSetTimeout(builder);
   msg.SetTimeout.addTimeout(builder, timeout);
   const inner = msg.SetTimeout.endSetTimeout(builder);

js/truncate.ts

 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 import * as msg from "gen/msg_generated";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import * as dispatch from "./dispatch";
 
 /** Truncates or extends the specified file synchronously, updating the size of
@@ -30,7 +30,7 @@ function req(
   name: string,
   len?: number
 ): [flatbuffers.Builder, msg.Any, flatbuffers.Offset] {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const name_ = builder.createString(name);
   len = len && len > 0 ? Math.floor(len) : 0;
   msg.Truncate.startTruncate(builder);

js/write_file.ts

 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 import * as msg from "gen/msg_generated";
-import { flatbuffers } from "flatbuffers";
+import * as flatbuffers from "./flatbuffers";
 import * as dispatch from "./dispatch";
 
 /** Write a new file, with given filename and data synchronously.
@@ -40,7 +40,7 @@ function req(
   data: Uint8Array,
   perm: number
 ): [flatbuffers.Builder, msg.Any, flatbuffers.Offset, Uint8Array] {
-  const builder = new flatbuffers.Builder();
+  const builder = flatbuffers.createBuilder();
   const filename_ = builder.createString(filename);
   msg.WriteFile.startWriteFile(builder);
   msg.WriteFile.addFilename(builder, filename_);

src/ops.rs

@@ -816,8 +816,8 @@ fn op_copy_file(
     // Once the issue is reolved, we should remove this workaround.
     if cfg!(unix) && !from.is_file() {
       return Err(errors::new(
-          ErrorKind::NotFound,
-          "File not found".to_string(),
+        ErrorKind::NotFound,
+        "File not found".to_string(),
       ));
     }
 

tools/http_server.py

@@ -57,6 +57,7 @@ def spawn():
 if __name__ == '__main__':
     try:
         spawn()
-        while True: sleep(100)
+        while True:
+            sleep(100)
     except KeyboardInterrupt:
         sys.exit()