1 files changed, 64 insertions, 0 deletions
diff --git a/mailnews/mime/src/mimepbuf.h b/mailnews/mime/src/mimepbuf.h
new file mode 100644
index 000000000..200b64a89
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+++ b/mailnews/mime/src/mimepbuf.h
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+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+#ifndef _MIMEPBUF_H_
+#define _MIMEPBUF_H_
+
+#include "mimei.h"
+#include "modmimee.h" // for MimeConverterOutputCallback
+
+/* This file provides the ability to save up the entire contents of a MIME
+   object (of arbitrary size), and then emit it all at once later.  The
+   buffering is done in an efficient way that works well for both very large
+   and very small objects.
+
+   This is used in two places:
+
+   = The implementation of multipart/alternative uses this code to do a
+     one-part-lookahead.  As it traverses its children, it moves forward
+     until it finds a part which cannot be displayed; and then it displays
+     the *previous* part (the last which *could* be displayed.)  This code
+     is used to hold the previous part until it is needed.
+*/
+
+/* An opaque object used to represent the buffered data.
+ */
+typedef struct MimePartBufferData MimePartBufferData;
+
+/* Create an empty part buffer object.
+ */
+extern MimePartBufferData *MimePartBufferCreate (void);
+
+/* Assert that the buffer is now full (EOF has been reached on the current
+   part.)  This will free some resources, but leaves the part in the buffer.
+   After calling MimePartBufferReset, the buffer may be used to store a
+   different object.
+ */
+void MimePartBufferClose (MimePartBufferData *data);
+
+/* Reset a part buffer object to the default state, discarding any currently-
+   buffered data.
+ */
+extern void MimePartBufferReset (MimePartBufferData *data);
+
+/* Free the part buffer itself, and discard any buffered data.
+ */
+extern void MimePartBufferDestroy (MimePartBufferData *data);
+
+/* Push a chunk of a MIME object into the buffer.
+ */
+extern int MimePartBufferWrite (MimePartBufferData *data,
+                const char *buf, int32_t size);
+
+/* Read the contents of the buffer back out.  This will invoke the provided
+   read_fn with successive chunks of data until the buffer has been drained.
+   The provided function may be called once, or multiple times.
+ */
+extern int
+MimePartBufferRead (MimePartBufferData *data,
+          MimeConverterOutputCallback read_fn,
+          void *closure);
+
+#endif /* _MIMEPBUF_H_ */