Bug 1199384 - Add shell function for writing a typed array to a file, r=sfink.

js/src/shell/OSObject.cpp

@@ -125,7 +125,7 @@ FileAsTypedArray(JSContext* cx, const char* pathname)
         JS_ReportError(cx, "can't open %s: %s", pathname, strerror(errno));
         return nullptr;
     }
-    AutoCloseInputFile autoClose(file);
+    AutoCloseFile autoClose(file);
 
     RootedObject obj(cx);
     if (fseek(file, 0, SEEK_END) != 0) {
@@ -210,6 +210,50 @@ osfile_readRelativeToScript(JSContext* cx, unsigned argc, Value* vp)
     return ReadFile(cx, argc, vp, true);
 }
 
+static bool
+osfile_writeTypedArrayToFile(JSContext* cx, unsigned argc, Value* vp)
+{
+    CallArgs args = CallArgsFromVp(argc, vp);
+
+    if (args.length() != 2 ||
+        !args[0].isString() ||
+        !args[1].isObject() ||
+        !args[1].toObject().is<TypedArrayObject>())
+    {
+        JS_ReportErrorNumber(cx, my_GetErrorMessage, nullptr,
+                             JSSMSG_INVALID_ARGS, "writeTypedArrayToFile");
+        return false;
+    }
+
+    RootedString givenPath(cx, args[0].toString());
+    RootedString str(cx, ResolvePath(cx, givenPath, RootRelative));
+    if (!str)
+        return false;
+
+    JSAutoByteString filename(cx, str);
+    if (!filename)
+        return false;
+
+    FILE* file = fopen(filename.ptr(), "wb");
+    if (!file) {
+        JS_ReportError(cx, "can't open %s: %s", filename.ptr(), strerror(errno));
+        return false;
+    }
+    AutoCloseFile autoClose(file);
+
+    TypedArrayObject* obj = &args[1].toObject().as<TypedArrayObject>();
+
+    if (fwrite(obj->viewData(), obj->bytesPerElement(), obj->length(), file) != obj->length() ||
+        !autoClose.release())
+    {
+        JS_ReportError(cx, "can't write %s", filename.ptr());
+        return false;
+    }
+
+    args.rval().setUndefined();
+    return true;
+}
+
 static bool
 Redirect(JSContext* cx, FILE* fp, HandleString relFilename)
 {
@@ -271,6 +315,10 @@ static const JSFunctionSpecWithHelp osfile_functions[] = {
 };
 
 static const JSFunctionSpecWithHelp osfile_unsafe_functions[] = {
+    JS_FN_HELP("writeTypedArrayToFile", osfile_writeTypedArrayToFile, 2, 0,
+"writeTypedArrayToFile(filename, data)",
+"  Write the contents of a typed array to the named file."),
+
     JS_FN_HELP("redirect", osfile_redirect, 2, 0,
 "redirect(stdoutFilename[, stderrFilename])",
 "  Redirect stdout and/or stderr to the named file. Pass undefined to avoid\n"

js/src/shell/js.cpp

@@ -573,7 +573,7 @@ Process(JSContext* cx, const char* filename, bool forceTTY)
             return;
         }
     }
-    AutoCloseInputFile autoClose(file);
+    AutoCloseFile autoClose(file);
 
     if (!forceTTY && !isatty(fileno(file))) {
         // It's not interactive - just execute it.
@@ -664,7 +664,7 @@ CreateMappedArrayBuffer(JSContext* cx, unsigned argc, Value* vp)
                              JSSMSG_CANT_OPEN, filename.ptr(), strerror(errno));
         return false;
     }
-    AutoCloseInputFile autoClose(file);
+    AutoCloseFile autoClose(file);
 
     if (!sizeGiven) {
         struct stat st;
@@ -1294,7 +1294,7 @@ js::shell::FileAsString(JSContext* cx, const char* pathname)
         JS_ReportError(cx, "can't open %s: %s", pathname, strerror(errno));
         return nullptr;
     }
-    AutoCloseInputFile autoClose(file);
+    AutoCloseFile autoClose(file);
 
     if (fseek(file, 0, SEEK_END) != 0) {
         JS_ReportError(cx, "can't seek end of %s", pathname);

js/src/shell/jsshell.h

@@ -1,3 +1,9 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
 #ifndef jsshell_js_h
 #define jsshell_js_h
 
@@ -23,15 +29,21 @@ my_ErrorReporter(JSContext* cx, const char* message, JSErrorReport* report);
 JSString*
 FileAsString(JSContext* cx, const char* pathname);
 
-class AutoCloseInputFile
+class AutoCloseFile
 {
   private:
     FILE* f_;
   public:
-    explicit AutoCloseInputFile(FILE* f) : f_(f) {}
-    ~AutoCloseInputFile() {
-        if (f_ && f_ != stdin)
-            fclose(f_);
+    explicit AutoCloseFile(FILE* f) : f_(f) {}
+    ~AutoCloseFile() {
+        (void) release();
+    }
+    bool release() {
+        bool success = true;
+        if (f_ && f_ != stdin && f_ != stdout && f_ != stderr)
+            success = !fclose(f_);
+        f_ = nullptr;
+        return success;
     }
 };