1 files changed, 145 insertions, 0 deletions
diff --git a/mailnews/base/util/nsMsgCompressOStream.cpp b/mailnews/base/util/nsMsgCompressOStream.cpp
new file mode 100644
index 000000000..0a0a69549
--- /dev/null
+++ b/mailnews/base/util/nsMsgCompressOStream.cpp
@@ -0,0 +1,145 @@
+/* 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 "nsMsgCompressOStream.h"
+#include "prio.h"
+#include "prmem.h"
+
+#define BUFFER_SIZE 16384
+
+nsMsgCompressOStream::nsMsgCompressOStream() :
+  m_zbuf(nullptr)
+{
+}
+
+nsMsgCompressOStream::~nsMsgCompressOStream()
+{
+  Close();
+}
+
+NS_IMPL_ISUPPORTS(nsMsgCompressOStream, nsIOutputStream)
+
+nsresult nsMsgCompressOStream::InitOutputStream(nsIOutputStream *rawStream)
+{
+  // protect against repeat calls
+  if (m_oStream)
+    return NS_ERROR_UNEXPECTED;
+
+  // allocate some memory for a buffer
+  m_zbuf = mozilla::MakeUnique<char[]>(BUFFER_SIZE);
+  if (!m_zbuf)
+    return NS_ERROR_OUT_OF_MEMORY;
+
+  // set up the zlib object
+  m_zstream.zalloc = Z_NULL;
+  m_zstream.zfree = Z_NULL;
+  m_zstream.opaque = Z_NULL;
+
+  // http://zlib.net/manual.html is rather silent on the topic, but
+  // perl's Compress::Raw::Zlib manual says:
+  // -WindowBits [...]
+  //  To compress an RFC 1951 data stream, set WindowBits to -MAX_WBITS.
+  if (deflateInit2(&m_zstream, Z_DEFAULT_COMPRESSION, Z_DEFLATED, 
+                   -MAX_WBITS, MAX_MEM_LEVEL, Z_DEFAULT_STRATEGY) != Z_OK)
+    return NS_ERROR_FAILURE;
+
+  m_oStream = rawStream;
+
+  return NS_OK;
+}
+
+/* void close (); */
+NS_IMETHODIMP nsMsgCompressOStream::Close()
+{
+  if (m_oStream)
+  {
+    m_oStream = nullptr;
+    deflateEnd(&m_zstream);
+  }
+  m_zbuf = nullptr;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMsgCompressOStream::Write(const char *buf, uint32_t count, uint32_t *result)
+{
+  if (!m_oStream)
+    return NS_BASE_STREAM_CLOSED;
+
+  m_zstream.next_in = (Bytef *) buf;
+  m_zstream.avail_in = count;
+
+  // keep looping until the buffer doesn't get filled
+  do
+  {
+    m_zstream.next_out = (Bytef *) m_zbuf.get();
+    m_zstream.avail_out = BUFFER_SIZE;
+    // Using "Z_SYNC_FLUSH" may cause excess flushes if the calling
+    // code does a lot of small writes.  An option with the IMAP
+    // protocol is to check the buffer for "\n" at the end, but
+    // in the interests of keeping this generic, don't optimise
+    // yet.  An alternative is to require ->Flush always, but that
+    // is likely to break callers.
+    int zr = deflate(&m_zstream, Z_SYNC_FLUSH);
+    if (zr == Z_STREAM_END || zr == Z_BUF_ERROR)
+      zr = Z_OK; // not an error for our purposes
+    if (zr != Z_OK)
+      return NS_ERROR_FAILURE;
+
+    uint32_t out_size = BUFFER_SIZE - m_zstream.avail_out;
+    const char *out_buf = m_zbuf.get();
+
+    // push everything in the buffer before repeating
+    while (out_size)
+    {
+      uint32_t out_result;
+      nsresult rv = m_oStream->Write(out_buf, out_size, &out_result);
+      NS_ENSURE_SUCCESS(rv, rv);
+      if (!out_result)
+	return NS_BASE_STREAM_CLOSED;
+      out_size -= out_result;
+      out_buf += out_result;
+    }
+
+  // http://www.zlib.net/manual.html says:
+  // If deflate returns with avail_out == 0, this function must be 
+  // called again with the same value of the flush parameter and
+  // more output space (updated avail_out), until the flush is 
+  // complete (deflate returns with non-zero avail_out). 
+  } while (!m_zstream.avail_out);
+
+  *result = count;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMsgCompressOStream::Flush(void)
+{
+  if (!m_oStream)
+    return NS_BASE_STREAM_CLOSED;
+  
+  return m_oStream->Flush();
+}
+
+NS_IMETHODIMP
+nsMsgCompressOStream::WriteFrom(nsIInputStream *inStr, uint32_t count, uint32_t *_retval)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsMsgCompressOStream::WriteSegments(nsReadSegmentFun reader, void * closure, uint32_t count, uint32_t *_retval)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+/* boolean isNonBlocking (); */
+NS_IMETHODIMP nsMsgCompressOStream::IsNonBlocking(bool *aNonBlocking)
+{
+  *aNonBlocking = false;
+  return NS_OK;
+}
+