Bug 1791721 - Create a dedicated interface for read write (input output) streams; r=xpcom-reviewers,necko-reviewers,nika,valentin

Differential Revision: https://phabricator.services.mozilla.com/D157786

dom/filehandle/ActorsParent.cpp

@@ -1165,7 +1165,7 @@ already_AddRefed<nsISupports> BackgroundMutableFileParentBase::CreateStream(
     return stream.forget();
   }
 
-  nsCOMPtr<nsIFileStream> stream;
+  nsCOMPtr<nsIRandomAccessStream> stream;
   rv = NS_NewLocalFileStream(getter_AddRefs(stream), mFile, -1, -1,
                              nsIFileStream::DEFER_OPEN);
   if (NS_WARN_IF(NS_FAILED(rv))) {

dom/simpledb/ActorsParent.cpp

@@ -1415,11 +1415,8 @@ nsresult SeekOp::DoDatabaseWork(nsIFileStream* aFileStream) {
   AssertIsOnIOThread();
   MOZ_ASSERT(aFileStream);
 
-  nsCOMPtr<nsISeekableStream> seekableStream = do_QueryInterface(aFileStream);
-  MOZ_ASSERT(seekableStream);
-
   nsresult rv =
-      seekableStream->Seek(nsISeekableStream::NS_SEEK_SET, mParams.offset());
+      aFileStream->Seek(nsISeekableStream::NS_SEEK_SET, mParams.offset());
 
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;

netwerk/base/nsFileStreams.cpp

@@ -876,8 +876,29 @@ nsresult nsFileStream::Create(REFNSIID aIID, void** aResult) {
   return stream->QueryInterface(aIID, aResult);
 }
 
-NS_IMPL_ISUPPORTS_INHERITED(nsFileStream, nsFileStreamBase, nsIInputStream,
+NS_IMPL_ISUPPORTS_INHERITED(nsFileStream, nsFileStreamBase,
-                            nsIOutputStream, nsIFileStream)
+                            nsIRandomAccessStream, nsIFileStream,
+                            nsIInputStream, nsIOutputStream)
+
+NS_IMETHODIMP
+nsFileStream::GetInputStream(nsIInputStream** aInputStream) {
+  nsCOMPtr<nsIInputStream> inputStream(this);
+
+  inputStream.forget(aInputStream);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFileStream::GetOutputStream(nsIOutputStream** aOutputStream) {
+  nsCOMPtr<nsIOutputStream> outputStream(this);
+
+  outputStream.forget(aOutputStream);
+  return NS_OK;
+}
+
+nsIInputStream* nsFileStream::InputStream() { return this; }
+
+nsIOutputStream* nsFileStream::OutputStream() { return this; }
 
 NS_IMETHODIMP
 nsFileStream::Init(nsIFile* file, int32_t ioFlags, int32_t perm,

netwerk/base/nsFileStreams.h

@@ -12,6 +12,7 @@
 #include "nsICloneableInputStream.h"
 #include "nsIInputStream.h"
 #include "nsIOutputStream.h"
+#include "nsIRandomAccessStream.h"
 #include "nsISafeOutputStream.h"
 #include "nsISeekableStream.h"
 #include "nsILineInputStream.h"
@@ -251,13 +252,16 @@ class nsSafeFileOutputStream : public nsAtomicFileOutputStream {
 ////////////////////////////////////////////////////////////////////////////////
 
 class nsFileStream : public nsFileStreamBase,
+                     public nsIFileStream,
                      public nsIInputStream,
-                     public nsIOutputStream,
+                     public nsIOutputStream {
-                     public nsIFileStream {
  public:
   static nsresult Create(REFNSIID aIID, void** aResult);
 
   NS_DECL_ISUPPORTS_INHERITED
+  NS_FORWARD_NSITELLABLESTREAM(nsFileStreamBase::)
+  NS_FORWARD_NSISEEKABLESTREAM(nsFileStreamBase::)
+  NS_DECL_NSIRANDOMACCESSSTREAM
   NS_DECL_NSIFILESTREAM
   NS_FORWARD_NSIINPUTSTREAM(nsFileStreamBase::)
 

netwerk/base/nsIFileStreams.idl

@@ -5,6 +5,7 @@
 
 #include "nsIInputStream.idl"
 #include "nsIOutputStream.idl"
+#include "nsIRandomAccessStream.idl"
 
 interface nsIEventTarget;
 interface nsIFile;
@@ -133,7 +134,7 @@ interface nsIFileOutputStream : nsIOutputStream
  * A stream that allows you to read from a file or stream to a file.
  */
 [scriptable, builtinclass, uuid(82cf605a-8393-4550-83ab-43cd5578e006)]
-interface nsIFileStream : nsISupports
+interface nsIFileStream : nsIRandomAccessStream
 {
     /**
      * @param file          file to read from or stream to

netwerk/base/nsNetUtil.cpp

@@ -1300,7 +1300,7 @@ nsresult NS_NewSafeLocalFileOutputStream(nsIOutputStream** result,
   return rv;
 }
 
-nsresult NS_NewLocalFileStream(nsIFileStream** result, nsIFile* file,
+nsresult NS_NewLocalFileStream(nsIRandomAccessStream** result, nsIFile* file,
                                int32_t ioFlags /* = -1 */,
                                int32_t perm /* = -1 */,
                                int32_t behaviorFlags /* = 0 */) {
@@ -1312,10 +1312,11 @@ nsresult NS_NewLocalFileStream(nsIFileStream** result, nsIFile* file,
   return rv;
 }
 
-mozilla::Result<nsCOMPtr<nsIFileStream>, nsresult> NS_NewLocalFileStream(
+mozilla::Result<nsCOMPtr<nsIRandomAccessStream>, nsresult>
-    nsIFile* file, int32_t ioFlags /* = -1 */, int32_t perm /* = -1 */,
+NS_NewLocalFileStream(nsIFile* file, int32_t ioFlags /* = -1 */,
-    int32_t behaviorFlags /* = 0 */) {
+                      int32_t perm /* = -1 */,
-  nsCOMPtr<nsIFileStream> stream;
+                      int32_t behaviorFlags /* = 0 */) {
+  nsCOMPtr<nsIRandomAccessStream> stream;
   const nsresult rv = NS_NewLocalFileStream(getter_AddRefs(stream), file,
                                             ioFlags, perm, behaviorFlags);
   if (NS_SUCCEEDED(rv)) {

netwerk/base/nsNetUtil.h

@@ -49,6 +49,7 @@ class nsIOutputStream;
 class nsIParentChannel;
 class nsIPersistentProperties;
 class nsIProxyInfo;
+class nsIRandomAccessStream;
 class nsIRequestObserver;
 class nsIStreamListener;
 class nsIStreamLoader;
@@ -513,13 +514,13 @@ nsresult NS_NewSafeLocalFileOutputStream(nsIOutputStream** result,
                                          int32_t perm = -1,
                                          int32_t behaviorFlags = 0);
 
-nsresult NS_NewLocalFileStream(nsIFileStream** result, nsIFile* file,
+nsresult NS_NewLocalFileStream(nsIRandomAccessStream** result, nsIFile* file,
                                int32_t ioFlags = -1, int32_t perm = -1,
                                int32_t behaviorFlags = 0);
 
-mozilla::Result<nsCOMPtr<nsIFileStream>, nsresult> NS_NewLocalFileStream(
+mozilla::Result<nsCOMPtr<nsIRandomAccessStream>, nsresult>
-    nsIFile* file, int32_t ioFlags = -1, int32_t perm = -1,
+NS_NewLocalFileStream(nsIFile* file, int32_t ioFlags = -1, int32_t perm = -1,
-    int32_t behaviorFlags = 0);
+                      int32_t behaviorFlags = 0);
 
 [[nodiscard]] nsresult NS_NewBufferedInputStream(
     nsIInputStream** aResult, already_AddRefed<nsIInputStream> aInputStream,

toolkit/components/telemetry/core/Telemetry.cpp

@@ -1952,7 +1952,7 @@ void WriteFailedProfileLock(nsIFile* aProfileDir) {
   if (NS_FAILED(rv) && rv != NS_ERROR_FILE_NOT_FOUND) {
     return;
   }
-  nsCOMPtr<nsIFileStream> fileStream;
+  nsCOMPtr<nsIRandomAccessStream> fileStream;
   rv = NS_NewLocalFileStream(getter_AddRefs(fileStream), file,
                              PR_RDWR | PR_CREATE_FILE, 0640);
   NS_ENSURE_SUCCESS_VOID(rv);
@@ -1968,11 +1968,9 @@ void WriteFailedProfileLock(nsIFile* aProfileDir) {
   ++failedLockCount;
   nsAutoCString bufStr;
   bufStr.AppendInt(static_cast<int>(failedLockCount));
-  nsCOMPtr<nsISeekableStream> seekStream = do_QueryInterface(fileStream);
-  NS_ENSURE_TRUE_VOID(seekStream);
   // If we read in an existing failed lock count, we need to reset the file ptr
   if (fileSize > 0) {
-    rv = seekStream->Seek(nsISeekableStream::NS_SEEK_SET, 0);
+    rv = fileStream->Seek(nsISeekableStream::NS_SEEK_SET, 0);
     NS_ENSURE_SUCCESS_VOID(rv);
   }
   nsCOMPtr<nsIOutputStream> outStream = do_QueryInterface(fileStream);
@@ -1987,7 +1985,7 @@ void WriteFailedProfileLock(nsIFile* aProfileDir) {
     bytes += written;
     bytesLeft -= written;
   } while (bytesLeft > 0);
-  seekStream->SetEOF();
+  fileStream->SetEOF();
 }
 
 void InitIOReporting(nsIFile* aXreDir) {

xpcom/io/moz.build

@@ -27,6 +27,7 @@ XPIDL_SOURCES += [
     "nsIObjectOutputStream.idl",
     "nsIOutputStream.idl",
     "nsIPipe.idl",
+    "nsIRandomAccessStream.idl",
     "nsISafeOutputStream.idl",
     "nsIScriptableBase64Encoder.idl",
     "nsIScriptableInputStream.idl",

xpcom/io/nsIRandomAccessStream.idl

@@ -0,0 +1,48 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 "nsISupports.idl"
+#include "nsISeekableStream.idl"
+
+interface nsIInputStream;
+interface nsIOutputStream;
+
+/**
+ * nsIRandomAccessStream
+ *
+ * An interface which supports both reading and writing to a storage starting
+ * at the current offset. Both the input stream and the output stream share the
+ * offset in the stream. Read operations invoked on the input stream start at
+ * the offset and advance it past the bytes read. Write operations invoked on
+ * the output stream start the offset and advance it past the bytes written.
+ * The offset can be set to an arbitrary value prior reading or writting. Each
+ * call to getInputStream or getOutputStream always returns the same object,
+ * rather than creating a new stream. It's recommended for objects implementing
+ * this interface to also implement nsIInputStream and nsIOutputStream, so they
+ * can be easilly used with e.g. NS_AsyncCopy.
+ */
+[scriptable, builtinclass, uuid(9b5904a8-886a-420f-a1d8-847de8ffc133)]
+interface nsIRandomAccessStream : nsISeekableStream
+{
+  /**
+   * This method always returns the same object.
+   */
+  nsIInputStream getInputStream();
+
+  /**
+   * This method always returns the same object.
+   */
+  nsIOutputStream getOutputStream();
+
+  /**
+   * Like getInputStream but infallible.
+   */
+  [notxpcom, nostdcall] nsIInputStream inputStream();
+
+  /**
+   * Like getOutputStream but infallible.
+   */
+  [notxpcom, nostdcall] nsIOutputStream outputStream();
+};