Bug 1565627. Stop using [array] in nsIBinaryInputStream. r=froydnj

Differential Revision: https://phabricator.services.mozilla.com/D37897

--HG--
extra : moz-landing-system : lando

xpcom/io/nsBinaryStream.cpp

@@ -737,34 +737,48 @@ nsBinaryInputStream::ReadString(nsAString& aString) {
   return NS_OK;
 }
 
+nsresult nsBinaryInputStream::ReadBytesToBuffer(uint32_t aLength,
+                                                uint8_t* aBuffer) {
+  uint32_t bytesRead;
+  nsresult rv = Read(reinterpret_cast<char*>(aBuffer), aLength, &bytesRead);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  if (bytesRead != aLength) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsBinaryInputStream::ReadBytes(uint32_t aLength, char** aResult) {
-  nsresult rv;
-  uint32_t bytesRead;
-  char* s;
-
-  s = reinterpret_cast<char*>(malloc(aLength));
+  char* s = static_cast<char*>(malloc(aLength));
   if (!s) {
     return NS_ERROR_OUT_OF_MEMORY;
   }
 
-  rv = Read(s, aLength, &bytesRead);
+  nsresult rv = ReadBytesToBuffer(aLength, reinterpret_cast<uint8_t*>(s));
   if (NS_FAILED(rv)) {
     free(s);
     return rv;
   }
-  if (bytesRead != aLength) {
-    free(s);
-    return NS_ERROR_FAILURE;
-  }
 
   *aResult = s;
   return NS_OK;
 }
 
 NS_IMETHODIMP
-nsBinaryInputStream::ReadByteArray(uint32_t aLength, uint8_t** aResult) {
-  return ReadBytes(aLength, reinterpret_cast<char**>(aResult));
+nsBinaryInputStream::ReadByteArray(uint32_t aLength,
+                                   nsTArray<uint8_t>& aResult) {
+  if (!aResult.SetLength(aLength, fallible)) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+  nsresult rv = ReadBytesToBuffer(aLength, aResult.Elements());
+  if (NS_FAILED(rv)) {
+    aResult.Clear();
+  }
+  return rv;
 }
 
 NS_IMETHODIMP

xpcom/io/nsBinaryStream.h

@@ -88,6 +88,10 @@ class nsBinaryInputStream final : public nsIObjectInputStream {
   nsCOMPtr<nsIStreamBufferAccess> mBufferAccess;
 
  private:
+  // Shared infrastructure for ReadBytes and ReadByteArray.  Callers
+  // are expected to provide a buffer that can contain aLength bytes.
+  nsresult ReadBytesToBuffer(uint32_t aLength, uint8_t* aBuffer);
+
   // virtual dtor since subclasses call our Release()
   virtual ~nsBinaryInputStream() {}
 };

xpcom/io/nsIBinaryInputStream.idl

@@ -65,8 +65,7 @@ interface nsIBinaryInputStream : nsIInputStream {
      *
      * @throws NS_ERROR_FAILURE if it can't read aLength bytes
      */
-    void readByteArray(in uint32_t aLength,
-                       [array, size_is(aLength), retval] out uint8_t aBytes);
+    Array<uint8_t> readByteArray(in uint32_t aLength);
 
     /**
      * Read opaque bytes from the stream, storing the results in an ArrayBuffer.