4 files changed, 74 insertions, 5 deletions

diff --git a/runtime/js/12_io.js b/runtime/js/12_io.js
index fe815c7ed..aa153e9fd 100644
--- a/runtime/js/12_io.js
+++ b/runtime/js/12_io.js
@@ -123,6 +123,66 @@
     return result;
   }
 
+  const READ_PER_ITER = 32 * 1024;
+
+  async function readAll(r) {
+    const buffers = [];
+
+    while (true) {
+      const buf = new Uint8Array(READ_PER_ITER);
+      const read = await r.read(buf);
+      if (typeof read == "number") {
+        buffers.push(new Uint8Array(buf.buffer, 0, read));
+      } else {
+        break;
+      }
+    }
+
+    let totalLen = 0;
+    for (const buf of buffers) {
+      totalLen += buf.byteLength;
+    }
+
+    const contents = new Uint8Array(totalLen);
+
+    let n = 0;
+    for (const buf of buffers) {
+      contents.set(buf, n);
+      n += buf.byteLength;
+    }
+
+    return contents;
+  }
+
+  function readAllSync(r) {
+    const buffers = [];
+
+    while (true) {
+      const buf = new Uint8Array(READ_PER_ITER);
+      const read = r.readSync(buf);
+      if (typeof read == "number") {
+        buffers.push(new Uint8Array(buf.buffer, 0, read));
+      } else {
+        break;
+      }
+    }
+
+    let totalLen = 0;
+    for (const buf of buffers) {
+      totalLen += buf.byteLength;
+    }
+
+    const contents = new Uint8Array(totalLen);
+
+    let n = 0;
+    for (const buf of buffers) {
+      contents.set(buf, n);
+      n += buf.byteLength;
+    }
+
+    return contents;
+  }
+
   window.__bootstrap.io = {
     iterSync,
     iter,
@@ -132,5 +192,7 @@
     readSync,
     write,
     writeSync,
+    readAll,
+    readAllSync,
   };
 })(this);
diff --git a/runtime/js/40_process.js b/runtime/js/40_process.js
index cd8015e94..a93818b95 100644
--- a/runtime/js/40_process.js
+++ b/runtime/js/40_process.js
@@ -4,7 +4,7 @@
 ((window) => {
   const core = window.Deno.core;
   const { File } = window.__bootstrap.files;
-  const { readAll } = window.__bootstrap.buffer;
+  const { readAll } = window.__bootstrap.io;
   const { assert, pathFromURL } = window.__bootstrap.util;
 
   function opKill(pid, signo) {
diff --git a/runtime/js/40_read_file.js b/runtime/js/40_read_file.js
index 63b05b877..0ca8f56e9 100644
--- a/runtime/js/40_read_file.js
+++ b/runtime/js/40_read_file.js
@@ -3,7 +3,7 @@
 
 ((window) => {
   const { open, openSync } = window.__bootstrap.files;
-  const { readAll, readAllSync } = window.__bootstrap.buffer;
+  const { readAll, readAllSync } = window.__bootstrap.io;
 
   function readFileSync(path) {
     const file = openSync(path);
diff --git a/runtime/js/40_write_file.js b/runtime/js/40_write_file.js
index 5964dec5f..4662849a5 100644
--- a/runtime/js/40_write_file.js
+++ b/runtime/js/40_write_file.js
@@ -3,7 +3,6 @@
 ((window) => {
   const { stat, statSync, chmod, chmodSync } = window.__bootstrap.fs;
   const { open, openSync } = window.__bootstrap.files;
-  const { writeAll, writeAllSync } = window.__bootstrap.buffer;
   const { build } = window.__bootstrap.build;
 
   function writeFileSync(
@@ -32,7 +31,11 @@
       chmodSync(path, options.mode);
     }
 
-    writeAllSync(file, data);
+    let nwritten = 0;
+    while (nwritten < data.length) {
+      nwritten += file.writeSync(data.subarray(nwritten));
+    }
+
     file.close();
   }
 
@@ -62,7 +65,11 @@
       await chmod(path, options.mode);
     }
 
-    await writeAll(file, data);
+    let nwritten = 0;
+    while (nwritten < data.length) {
+      nwritten += await file.write(data.subarray(nwritten));
+    }
+
     file.close();
   }