Bug 1754040 - Clean up common shared WriteSegments helper functions, r=necko-reviewers,xpcom-reviewers,mccr8

These helper methods are similar to the related ones for
nsIInputStream::ReadSegments, and can be used to implement
nsIOutputStream::Write and nsIOutputStream::WriteFrom in terms of
WriteSegments.

There were various places which used manual copies of these methods, which are
being unified.

Differential Revision: https://phabricator.services.mozilla.com/D138334

dom/quota/EncryptingOutputStream.cpp

@@ -23,7 +23,7 @@ EncryptingOutputStreamBase::EncryptingOutputStreamBase(
 NS_IMETHODIMP EncryptingOutputStreamBase::Write(const char* aBuf,
                                                 uint32_t aCount,
                                                 uint32_t* aResultOut) {
-  return WriteSegments(NS_CopySegmentToBuffer, const_cast<char*>(aBuf), aCount,
+  return WriteSegments(NS_CopyBufferToSegment, const_cast<char*>(aBuf), aCount,
                        aResultOut);
 }
 

dom/quota/MemoryOutputStream.cpp

@@ -49,7 +49,7 @@ MemoryOutputStream::Close() {
 NS_IMETHODIMP
 MemoryOutputStream::Write(const char* aBuf, uint32_t aCount,
                           uint32_t* _retval) {
-  return WriteSegments(NS_CopySegmentToBuffer, (char*)aBuf, aCount, _retval);
+  return WriteSegments(NS_CopyBufferToSegment, (char*)aBuf, aCount, _retval);
 }
 
 NS_IMETHODIMP

netwerk/base/nsBufferedStreams.cpp

@@ -1011,17 +1011,10 @@ nsBufferedOutputStream::Finish() {
   return NS_OK;
 }
 
-static nsresult nsReadFromInputStream(nsIOutputStream* outStr, void* closure,
-                                      char* toRawSegment, uint32_t offset,
-                                      uint32_t count, uint32_t* readCount) {
-  nsIInputStream* fromStream = (nsIInputStream*)closure;
-  return fromStream->Read(toRawSegment, count, readCount);
-}
-
 NS_IMETHODIMP
 nsBufferedOutputStream::WriteFrom(nsIInputStream* inStr, uint32_t count,
                                   uint32_t* _retval) {
-  return WriteSegments(nsReadFromInputStream, inStr, count, _retval);
+  return WriteSegments(NS_CopyStreamToSegment, inStr, count, _retval);
 }
 
 NS_IMETHODIMP

xpcom/io/SnappyCompressOutputStream.cpp

@@ -79,7 +79,7 @@ SnappyCompressOutputStream::Flush() {
 NS_IMETHODIMP
 SnappyCompressOutputStream::Write(const char* aBuf, uint32_t aCount,
                                   uint32_t* aResultOut) {
-  return WriteSegments(NS_CopySegmentToBuffer, const_cast<char*>(aBuf), aCount,
+  return WriteSegments(NS_CopyBufferToSegment, const_cast<char*>(aBuf), aCount,
                        aResultOut);
 }
 

xpcom/io/nsPipe3.cpp

@@ -1719,19 +1719,10 @@ nsPipeOutputStream::WriteSegments(nsReadSegmentFun aReader, void* aClosure,
   return rv;
 }
 
-static nsresult nsReadFromRawBuffer(nsIOutputStream* aOutStr, void* aClosure,
-                                    char* aToRawSegment, uint32_t aOffset,
-                                    uint32_t aCount, uint32_t* aReadCount) {
-  const char* fromBuf = (const char*)aClosure;
-  memcpy(aToRawSegment, &fromBuf[aOffset], aCount);
-  *aReadCount = aCount;
-  return NS_OK;
-}
-
 NS_IMETHODIMP
 nsPipeOutputStream::Write(const char* aFromBuf, uint32_t aBufLen,
                           uint32_t* aWriteCount) {
-  return WriteSegments(nsReadFromRawBuffer, (void*)aFromBuf, aBufLen,
+  return WriteSegments(NS_CopyBufferToSegment, (void*)aFromBuf, aBufLen,
                        aWriteCount);
 }
 
@@ -1741,17 +1732,11 @@ nsPipeOutputStream::Flush(void) {
   return NS_OK;
 }
 
-static nsresult nsReadFromInputStream(nsIOutputStream* aOutStr, void* aClosure,
-                                      char* aToRawSegment, uint32_t aOffset,
-                                      uint32_t aCount, uint32_t* aReadCount) {
-  nsIInputStream* fromStream = (nsIInputStream*)aClosure;
-  return fromStream->Read(aToRawSegment, aCount, aReadCount);
-}
-
 NS_IMETHODIMP
 nsPipeOutputStream::WriteFrom(nsIInputStream* aFromStream, uint32_t aCount,
                               uint32_t* aWriteCount) {
-  return WriteSegments(nsReadFromInputStream, aFromStream, aCount, aWriteCount);
+  return WriteSegments(NS_CopyStreamToSegment, aFromStream, aCount,
+                       aWriteCount);
 }
 
 NS_IMETHODIMP

xpcom/io/nsStreamUtils.cpp

@@ -766,7 +766,7 @@ nsresult NS_CopySegmentToBuffer(nsIInputStream* aInStr, void* aClosure,
   return NS_OK;
 }
 
-nsresult NS_CopySegmentToBuffer(nsIOutputStream* aOutStr, void* aClosure,
+nsresult NS_CopyBufferToSegment(nsIOutputStream* aOutStr, void* aClosure,
                                 char* aBuffer, uint32_t aOffset,
                                 uint32_t aCount, uint32_t* aCountRead) {
   const char* fromBuf = static_cast<const char*>(aClosure);
@@ -775,6 +775,13 @@ nsresult NS_CopySegmentToBuffer(nsIOutputStream* aOutStr, void* aClosure,
   return NS_OK;
 }
 
+nsresult NS_CopyStreamToSegment(nsIOutputStream* aOutputStream, void* aClosure,
+                                char* aToSegment, uint32_t aFromOffset,
+                                uint32_t aCount, uint32_t* aReadCount) {
+  nsIInputStream* fromStream = static_cast<nsIInputStream*>(aClosure);
+  return fromStream->Read(aToSegment, aCount, aReadCount);
+}
+
 nsresult NS_DiscardSegment(nsIInputStream* aInStr, void* aClosure,
                            const char* aBuffer, uint32_t aOffset,
                            uint32_t aCount, uint32_t* aCountWritten) {

xpcom/io/nsStreamUtils.h

@@ -208,7 +208,19 @@ extern nsresult NS_CopySegmentToBuffer(nsIInputStream* aInputStream,
  *
  * @see nsIOutputStream.idl for a description of this function's parameters.
  */
-extern nsresult NS_CopySegmentToBuffer(nsIOutputStream* aOutputStream,
+extern nsresult NS_CopyBufferToSegment(nsIOutputStream* aOutputStream,
+                                       void* aClosure, char* aToSegment,
+                                       uint32_t aFromOffset, uint32_t aCount,
+                                       uint32_t* aReadCount);
+
+/**
+ * This function is intended to be passed to nsIOutputStream::WriteSegments to
+ * copy data into the nsIOutputStream from a nsIInputStream passed as the
+ * aClosure parameter to the WriteSegments function.
+ *
+ * @see nsIOutputStream.idl for a description of this function's parameters.
+ */
+extern nsresult NS_CopyStreamToSegment(nsIOutputStream* aOutputStream,
                                        void* aClosure, char* aToSegment,
                                        uint32_t aFromOffset, uint32_t aCount,
                                        uint32_t* aReadCount);