Setup for message repair

Setup for message repair

[Daniel Kahn Gillmor]

This series of two commits offers no functional change, but it is a
useful basis for two outstanding series that i'd like to get merged:

 * "mixed up" message mangling
 * skipping legacy-display protected headers

Both of these series include code that touches lightly on notmuch's
MIME tree-crawling code, both for rendering ("notmuch show" and
"notmuch reply") and during indexing.

I'm hoping that these changes will make it somewhat less painful to
think about merging both series.

     --dkg

[PATCH 1/2] mime-node: split out _mime_node_set_up_part

[Daniel Kahn Gillmor]

This is a code reorganization that should have no functional effect,
but will make future changes simpler, because a future commit will
reuse the _mime_node_set_up_part functionality without touching
_mime_node_create.

In the course of splitting out this function, I noticed a comment in
the codebase that referred to an older name of _mime_node_create
(message_part_create), where this functionality originally resided.
I've fixed that comment to refer to the new function instead.

Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
---
 mime-node.c | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/mime-node.c b/mime-node.c
index 3492bcd0..0be03de7 100644
--- a/mime-node.c
+++ b/mime-node.c
@@ -264,14 +264,15 @@ node_decrypt_and_verify (mime_node_t *node, GMimeObject *part)
 	g_error_free (err);
 }
 
+static bool
+_mime_node_set_up_part (mime_node_t *node, GMimeObject *part, int numchild);
+
 static mime_node_t *
 _mime_node_create (mime_node_t *parent, GMimeObject *part, int numchild)
 {
     mime_node_t *node = talloc_zero (parent, mime_node_t);
-    notmuch_status_t status;
 
     /* Set basic node properties */
-    node->part = part;
     node->ctx = parent->ctx;
     if (!talloc_reference (node, node->ctx)) {
 	fprintf (stderr, "Out of memory.\n");
@@ -282,10 +283,23 @@ _mime_node_create (mime_node_t *parent, GMimeObject *part, int numchild)
     node->part_num = node->next_part_num = -1;
     node->next_child = 0;
 
+    if (_mime_node_set_up_part (node, part, numchild))
+	return node;
+    talloc_free (node);
+    return NULL;
+}
+
+/* associate a MIME part with a node. */
+static bool
+_mime_node_set_up_part (mime_node_t *node, GMimeObject *part, int numchild) {
+    notmuch_status_t status;
+
     /* Deal with the different types of parts */
     if (GMIME_IS_PART (part)) {
+	node->part = part;
 	node->nchildren = 0;
     } else if (GMIME_IS_MULTIPART (part)) {
+	node->part = part;
 	node->nchildren = g_mime_multipart_get_count (GMIME_MULTIPART (part));
     } else if (GMIME_IS_MESSAGE_PART (part)) {
 	/* Promote part to an envelope and open it */
@@ -297,11 +311,10 @@ _mime_node_create (mime_node_t *parent, GMimeObject *part, int numchild)
     } else {
 	fprintf (stderr, "Warning: Unknown mime part type: %s.\n",
 		 g_type_name (G_OBJECT_TYPE (part)));
-	talloc_free (node);
-	return NULL;
+	return false;
     }
 
-    /* Handle PGP/MIME parts */
+    /* Handle PGP/MIME parts (by definition not cryptographic payload parts) */
     if (GMIME_IS_MULTIPART_ENCRYPTED (part) && (node->ctx->crypto->decrypt != NOTMUCH_DECRYPT_FALSE)) {
 	if (node->nchildren != 2) {
 	    /* this violates RFC 3156 section 4, so we won't bother with it. */
@@ -321,12 +334,12 @@ _mime_node_create (mime_node_t *parent, GMimeObject *part, int numchild)
 	    node_verify (node, part);
 	}
     } else {
-	status = _notmuch_message_crypto_potential_payload (node->ctx->msg_crypto, part, parent ? parent->part : NULL, numchild);
+	status = _notmuch_message_crypto_potential_payload (node->ctx->msg_crypto, part, node->parent ? node->parent->part : NULL, numchild);
 	if (status)
 	    fprintf (stderr, "Warning: failed to record potential crypto payload (%s).\n", notmuch_status_to_string (status));
     }
 
-    return node;
+    return true;
 }
 
 mime_node_t *
@@ -347,7 +360,7 @@ mime_node_child (mime_node_t *parent, int child)
     } else if (GMIME_IS_MESSAGE (parent->part)) {
 	sub = g_mime_message_get_mime_part (GMIME_MESSAGE (parent->part));
     } else {
-	/* This should have been caught by message_part_create */
+	/* This should have been caught by _mime_node_set_up_part */
 	INTERNAL_ERROR ("Unexpected GMimeObject type: %s",
 			g_type_name (G_OBJECT_TYPE (parent->part)));
     }
-- 
2.20.1

[PATCH 2/2] repair: set up codebase for repair functionality

[Daniel Kahn Gillmor]

This adds no functionality directly, but is a useful starting point
for adding new repair functionality.

Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
---
 doc/man7/notmuch-properties.rst | 12 ++++++++++++
 lib/notmuch-private.h           |  1 +
 notmuch-client.h                |  1 +
 util/Makefile.local             |  1 +
 util/repair.c                   | 21 +++++++++++++++++++++
 util/repair.h                   | 17 +++++++++++++++++
 6 files changed, 53 insertions(+)
 create mode 100644 util/repair.c
 create mode 100644 util/repair.h

diff --git a/doc/man7/notmuch-properties.rst b/doc/man7/notmuch-properties.rst
index 802e6763..2e610683 100644
--- a/doc/man7/notmuch-properties.rst
+++ b/doc/man7/notmuch-properties.rst
@@ -109,6 +109,18 @@ of its normal activity.
     example, an AES-128 key might be stashed in a notmuch property as:
     ``session-key=7:14B16AF65536C28AF209828DFE34C9E0``.
 
+**index.repaired**
+
+    Some messages arrive in forms that are confusing to view; they can
+    be mangled by mail transport agents, or the sending mail user
+    agent may structure them in a way that is confusing.  If notmuch
+    knows how to both detect and repair such a problematic message, it
+    will do so during indexing.
+
+    If it applies a message repair during indexing, it will use the
+    ``index.repaired`` property to note the type of repair(s) it
+    performed.
+
 SEE ALSO
 ========
 
diff --git a/lib/notmuch-private.h b/lib/notmuch-private.h
index 6fc5b366..ff3c6bbe 100644
--- a/lib/notmuch-private.h
+++ b/lib/notmuch-private.h
@@ -53,6 +53,7 @@ NOTMUCH_BEGIN_DECLS
 #include "error_util.h"
 #include "string-util.h"
 #include "crypto.h"
+#include "repair.h"
 
 #ifdef DEBUG
 # define DEBUG_DATABASE_SANITY 1
diff --git a/notmuch-client.h b/notmuch-client.h
index 39e26f2e..16fd4d55 100644
--- a/notmuch-client.h
+++ b/notmuch-client.h
@@ -52,6 +52,7 @@
 
 #include "talloc-extra.h"
 #include "crypto.h"
+#include "repair.h"
 
 #define unused(x) x __attribute__ ((unused))
 
diff --git a/util/Makefile.local b/util/Makefile.local
index 46f8af3a..f5d72f79 100644
--- a/util/Makefile.local
+++ b/util/Makefile.local
@@ -6,6 +6,7 @@ extra_cflags += -I$(srcdir)/$(dir)
 libnotmuch_util_c_srcs := $(dir)/xutil.c $(dir)/error_util.c $(dir)/hex-escape.c \
 		  $(dir)/string-util.c $(dir)/talloc-extra.c $(dir)/zlib-extra.c \
 		$(dir)/util.c $(dir)/gmime-extra.c $(dir)/crypto.c \
+		$(dir)/repair.c \
 		$(dir)/unicode-util.c
 
 libnotmuch_util_modules := $(libnotmuch_util_c_srcs:.c=.o)
diff --git a/util/repair.c b/util/repair.c
new file mode 100644
index 00000000..f91c1244
--- /dev/null
+++ b/util/repair.c
@@ -0,0 +1,21 @@
+/* notmuch - Not much of an email program, (just index and search)
+ *
+ * Copyright © 2019 Daniel Kahn Gillmor
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see https://www.gnu.org/licenses/ .
+ *
+ * Authors: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
+ */
+
+#include "repair.h"
diff --git a/util/repair.h b/util/repair.h
new file mode 100644
index 00000000..70e2b7bc
--- /dev/null
+++ b/util/repair.h
@@ -0,0 +1,17 @@
+#ifndef _REPAIR_H
+#define _REPAIR_H
+
+#include "gmime-extra.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* This is a collection of message structure and message format repair
+ * techniques that are designed to improve the user experience of
+ * notmuch */
+
+#ifdef __cplusplus
+}
+#endif
+#endif
-- 
2.20.1