[balsa] New files implementing GMimeFilterHeader

[Peter Bloomfield <peterb src gnome org>]

commit 1b44ee5519e5a5933fdd2110ffea3916018c88ca
Author: Albrecht Dreß <albrecht dress arcor de>
Date:   Tue Feb 7 22:21:14 2017 -0500

    New files implementing GMimeFilterHeader
    
    GMimeFilterHeader is a GMimeFilter for removing certain headers from a
    GMimeMessage.

 libbalsa/gmime-filter-header.c |  158 ++++++++++++++++++++++++++++++++++++++++
 libbalsa/gmime-filter-header.h |   51 +++++++++++++
 2 files changed, 209 insertions(+), 0 deletions(-)
---
diff --git a/libbalsa/gmime-filter-header.c b/libbalsa/gmime-filter-header.c
new file mode 100644
index 0000000..b5d27a1
--- /dev/null
+++ b/libbalsa/gmime-filter-header.c
@@ -0,0 +1,158 @@
+/* -*-mode:c; c-style:k&r; c-basic-offset:4; -*- */
+/* GMime message header filter
+ * Written/Copyright (c) by Albrecht Dreß <albrecht dress arcor de> 2017
+ * This module remove RFC 822 massage headers which shall not be sent to the MTA from from a message stream, 
including Bcc, Status,
+ * X-Status and X-Balsa-*.
+ *
+ * The basic structure of this file has been shamelessly stolen from the gmime-filter-* files, written by 
Jeffrey Stedfast.
+ *
+ * This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser 
General Public License
+ * as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any 
later version.
+ *
+ * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even 
the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more 
details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with this library; if not, 
write to the Free
+ * Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include <string.h>
+#include "gmime-filter-header.h"
+
+static void g_mime_filter_header_class_init(GMimeFilterHeaderClass *klass);
+static void g_mime_filter_header_finalize(GObject *object);
+
+static GMimeFilter *filter_copy(GMimeFilter *filter);
+static void filter_filter(GMimeFilter *filter, char *in, size_t len, size_t prespace, char **out, size_t 
*outlen,
+                                                 size_t *outprespace);
+static void filter_complete(GMimeFilter *filter, char *in, size_t len, size_t prespace, char **out, size_t 
*outlen,
+                                                       size_t *outprespace);
+static void filter_reset(GMimeFilter *filter);
+
+
+G_DEFINE_TYPE(GMimeFilterHeader, g_mime_filter_header, GMIME_TYPE_FILTER)
+
+
+static GMimeFilterClass *parent_class = NULL;
+
+
+static void
+g_mime_filter_header_class_init(GMimeFilterHeaderClass *klass)
+{
+       GObjectClass *object_class = G_OBJECT_CLASS(klass);
+       GMimeFilterClass *filter_class = GMIME_FILTER_CLASS(klass);
+
+       parent_class = g_type_class_ref(GMIME_TYPE_FILTER);
+
+       object_class->finalize = g_mime_filter_header_finalize;
+
+       filter_class->copy = filter_copy;
+       filter_class->filter = filter_filter;
+       filter_class->complete = filter_complete;
+       filter_class->reset = filter_reset;
+}
+
+static void
+g_mime_filter_header_init(GMimeFilterHeader *self)
+{
+       self->headers_done = FALSE;
+       self->drop_header = FALSE;
+}
+
+static void
+g_mime_filter_header_finalize(GObject *object)
+{
+       G_OBJECT_CLASS(parent_class)->finalize(object);
+}
+
+static GMimeFilter *
+filter_copy(GMimeFilter *filter)
+{
+       return g_mime_filter_header_new();
+}
+
+static void
+filter_filter(GMimeFilter *filter, char *inbuf, size_t inlen, size_t prespace,
+                 char **outbuf, size_t *outlen, size_t *outprespace)
+{
+       GMimeFilterHeader *self = GMIME_FILTER_HEADER(filter);
+
+       g_mime_filter_set_size(filter, inlen, FALSE);
+
+       if (self->headers_done) {
+               memcpy(filter->outbuf, inbuf, inlen);
+               *outlen = inlen;
+       } else {
+               gchar *newline;
+               gchar *outptr;
+
+               outptr = filter->outbuf;
+               *outlen = 0U;
+               newline = memchr(inbuf, '\n', inlen);
+               while ((newline != NULL) && !self->headers_done) {
+                       size_t count;
+
+                       /* number of chars in this line */
+                       count = (newline - inbuf) + 1U;
+
+                       /* check for for folded header continuation */
+                       if ((inbuf[0] == ' ') || (inbuf[0] == '\t')) {
+                               /* nothing to do, do not change the state */
+                       } else if (newline == inbuf) {
+                               self->headers_done = TRUE;
+                       } else if (((count >= 4U) && (g_ascii_strncasecmp(inbuf, "Bcc:", 4U) == 0)) ||
+                                          ((count >= 7U) && (g_ascii_strncasecmp(inbuf, "Status:", 7U) == 
0)) ||
+                                          ((count >= 9U) && (g_ascii_strncasecmp(inbuf, "X-Status:", 9U) == 
0)) ||
+                                          ((count >= 8U) && (g_ascii_strncasecmp(inbuf, "X-Balsa-", 8U) == 
0))) {
+                               self->drop_header = TRUE;
+                       } else {
+                               self->drop_header = FALSE;
+                       }
+
+                       /* copy if we want to keep this header */
+                       if (!self->drop_header) {
+                               memcpy(outptr, inbuf, count);
+                               outptr = &outptr[count];
+                               *outlen += count;
+                       }
+
+                       /* adjust */
+                       inbuf = &inbuf[count];
+                       inlen -= count;
+                       if (!self->headers_done && (inlen > 0)) {
+                               newline = memchr(inbuf, '\n', inlen);
+                       } else {
+                               newline = NULL;
+                       }
+               }
+
+               /* back up left-over data */
+               if (inlen > 0U) {
+                       g_mime_filter_backup(filter, inbuf, inlen);
+               }
+       }
+       *outprespace = filter->outpre;
+       *outbuf = filter->outbuf;
+}
+
+static void
+filter_complete(GMimeFilter *filter, char *inbuf, size_t inlen, size_t prespace,
+                               char **outbuf, size_t *outlen, size_t *outprespace)
+{
+       filter_filter(filter, inbuf, inlen, prespace, outbuf, outlen, outprespace);
+}
+
+static void
+filter_reset(GMimeFilter *filter)
+{
+}
+
+GMimeFilter *
+g_mime_filter_header_new()
+{
+       GMimeFilterHeader *header;
+
+       header = g_object_newv(GMIME_TYPE_FILTER_HEADER, 0, NULL);
+
+       return (GMimeFilter *) header;
+}
diff --git a/libbalsa/gmime-filter-header.h b/libbalsa/gmime-filter-header.h
new file mode 100644
index 0000000..34095aa
--- /dev/null
+++ b/libbalsa/gmime-filter-header.h
@@ -0,0 +1,51 @@
+/* -*-mode:c; c-style:k&r; c-basic-offset:4; -*- */
+/* GMime message header filter
+ * Written/Copyright (c) by Albrecht Dreß <albrecht dress arcor de> 2017
+ * This module remove RFC 822 massage headers which shall not be sent to the MTA from from a message stream, 
including Bcc, Status,
+ * X-Status and X-Balsa-*.
+ *
+ * The basic structure of this file has been shamelessly stolen from the gmime-filter-* files, written by 
Jeffrey Stedfast.
+ *
+ * This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser 
General Public License
+ * as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any 
later version.
+ *
+ * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even 
the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more 
details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with this library; if not, 
write to the Free
+ * Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#ifndef GMIME_FILTER_HEADER_H__
+#define GMIME_FILTER_HEADER_H__
+
+#include <gmime/gmime-filter.h>
+
+G_BEGIN_DECLS
+
+#define GMIME_TYPE_FILTER_HEADER            (g_mime_filter_header_get_type())
+#define GMIME_FILTER_HEADER(obj)            (G_TYPE_CHECK_INSTANCE_CAST((obj), GMIME_TYPE_FILTER_HEADER, 
GMimeFilterHeader))
+#define GMIME_FILTER_HEADER_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST((klass), GMIME_TYPE_FILTER_HEADER, 
GMimeFilterHeaderClass))
+#define GMIME_IS_FILTER_HEADER(obj)         (G_TYPE_CHECK_INSTANCE_TYPE((obj), GMIME_TYPE_FILTER_HEADER))
+#define GMIME_IS_FILTER_HEADER_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass), GMIME_TYPE_FILTER_HEADER))
+#define GMIME_FILTER_HEADER_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS((obj), GMIME_TYPE_FILTER_HEADER, 
GMimeFilterHeaderClass))
+
+typedef struct _GMimeFilterHeader GMimeFilterHeader;
+typedef struct _GMimeFilterHeaderClass GMimeFilterHeaderClass;
+
+struct _GMimeFilterHeader {
+       GMimeFilter parent_object;
+       gboolean headers_done;
+       gboolean drop_header;
+};
+
+struct _GMimeFilterHeaderClass {
+       GMimeFilterClass parent_class;
+};
+
+GType g_mime_filter_header_get_type(void);
+GMimeFilter *g_mime_filter_header_new(void);
+
+G_END_DECLS
+
+#endif /* GMIME_FILTER_HEADER_H__ */