1 files changed, 117 insertions, 0 deletions
diff --git a/xpcom/io/nsScriptableInputStream.cpp b/xpcom/io/nsScriptableInputStream.cpp
new file mode 100644
index 0000000000..5f8b139c6f
--- /dev/null
+++ b/xpcom/io/nsScriptableInputStream.cpp
@@ -0,0 +1,117 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+#include "nsScriptableInputStream.h"
+#include "nsString.h"
+
+NS_IMPL_ISUPPORTS(nsScriptableInputStream, nsIScriptableInputStream)
+
+// nsIScriptableInputStream methods
+NS_IMETHODIMP
+nsScriptableInputStream::Close() {
+  if (!mInputStream) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  return mInputStream->Close();
+}
+
+NS_IMETHODIMP
+nsScriptableInputStream::Init(nsIInputStream* aInputStream) {
+  if (!aInputStream) {
+    return NS_ERROR_NULL_POINTER;
+  }
+  mInputStream = aInputStream;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsScriptableInputStream::Available(uint64_t* aResult) {
+  if (!mInputStream) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  return mInputStream->Available(aResult);
+}
+
+NS_IMETHODIMP
+nsScriptableInputStream::Read(uint32_t aCount, char** aResult) {
+  nsresult rv = NS_OK;
+  uint64_t count64 = 0;
+  char* buffer = nullptr;
+
+  if (!mInputStream) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  rv = mInputStream->Available(&count64);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  // bug716556 - Ensure count+1 doesn't overflow
+  uint32_t count =
+      XPCOM_MIN((uint32_t)XPCOM_MIN<uint64_t>(count64, aCount), UINT32_MAX - 1);
+  buffer = (char*)malloc(count + 1);  // make room for '\0'
+  if (!buffer) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  rv = ReadHelper(buffer, count);
+  if (NS_FAILED(rv)) {
+    free(buffer);
+    return rv;
+  }
+
+  buffer[count] = '\0';
+  *aResult = buffer;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsScriptableInputStream::ReadBytes(uint32_t aCount, nsACString& aResult) {
+  if (!mInputStream) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  if (!aResult.SetLength(aCount, mozilla::fallible)) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  MOZ_ASSERT(aResult.Length() == aCount);
+  char* ptr = aResult.BeginWriting();
+  nsresult rv = ReadHelper(ptr, aCount);
+  if (NS_FAILED(rv)) {
+    aResult.Truncate();
+  }
+  return rv;
+}
+
+nsresult nsScriptableInputStream::ReadHelper(char* aBuffer, uint32_t aCount) {
+  uint32_t totalBytesRead = 0;
+  while (1) {
+    uint32_t bytesRead;
+    nsresult rv = mInputStream->Read(aBuffer + totalBytesRead,
+                                     aCount - totalBytesRead, &bytesRead);
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+
+    totalBytesRead += bytesRead;
+    if (totalBytesRead == aCount) {
+      break;
+    }
+
+    // If we have read zero bytes, we have hit EOF.
+    if (bytesRead == 0) {
+      return NS_ERROR_FAILURE;
+    }
+  }
+  return NS_OK;
+}
+
+nsresult nsScriptableInputStream::Create(REFNSIID aIID, void** aResult) {
+  RefPtr<nsScriptableInputStream> sis = new nsScriptableInputStream();
+  return sis->QueryInterface(aIID, aResult);
+}