[PATCH v2 1/4] cli: add --from option to reply to restrict guessing of the From: header.

[Mark Walters]

Add an option --from= to notmuch-reply.c to restrict guessing of the
From: header. The existing logic looks as the main headers, then at
the delivery headers, and finally defaults to the config file address.

This patch allows the user to restrict which of these guesses are
made.  Currently the supported values are:
       default|fallback-all    current behaviour
       fallback-received       fallback to delivery headers but not config file
       fallback-none	       only look at from/reply-to/to/cc/ headers
       none	 	       From: header is always left empty

If the code does not find an allowed address it outputs an empty From:
line and the caller can decide how to respond.
---
 notmuch-reply.c |   45 ++++++++++++++++++++++++++++++++++++---------
 1 files changed, 36 insertions(+), 9 deletions(-)

diff --git a/notmuch-reply.c b/notmuch-reply.c
index f55b1d2..8c73cb7 100644
--- a/notmuch-reply.c
+++ b/notmuch-reply.c
@@ -24,6 +24,15 @@
 #include "gmime-filter-reply.h"
 #include "gmime-filter-headers.h"
 
+/* The order here matters as we use '<' when deciding how to behave. */
+enum {
+    FROM_FALLBACK_ALL,
+    FROM_FALLBACK_RECEIVED,
+    FROM_FALLBACK_NONE,
+    FROM_NONE,
+    FROM_PRIMARY
+};
+
 static void
 reply_headers_message_part (GMimeMessage *message);
 
@@ -510,7 +519,8 @@ notmuch_reply_format_default(void *ctx,
 			     notmuch_config_t *config,
 			     notmuch_query_t *query,
 			     notmuch_show_params_t *params,
-			     notmuch_bool_t reply_all)
+			     notmuch_bool_t reply_all,
+			     int from_select)
 {
     GMimeMessage *reply;
     notmuch_messages_t *messages;
@@ -542,15 +552,22 @@ notmuch_reply_format_default(void *ctx,
 	from_addr = add_recipients_from_message (reply, config, message,
 						 reply_all);
 
-	if (from_addr == NULL)
+	if (from_addr == NULL && from_select <= FROM_FALLBACK_RECEIVED)
 	    from_addr = guess_from_received_header (config, message);
 
-	if (from_addr == NULL)
+	if ((from_addr == NULL && from_select <= FROM_FALLBACK_ALL) ||
+	    from_select == FROM_PRIMARY)
 	    from_addr = notmuch_config_get_user_primary_email (config);
 
-	from_addr = talloc_asprintf (ctx, "%s <%s>",
-				     notmuch_config_get_user_name (config),
-				     from_addr);
+	/* If we have an address and we want an address print
+	 * it. Otherwise set an empty From: header. */
+	if (from_addr != NULL && from_select != FROM_NONE) {
+	    from_addr = talloc_asprintf (ctx, "%s <%s>",
+					 notmuch_config_get_user_name (config),
+					 from_addr);
+	} else {
+	    from_addr = talloc_strdup (ctx, "");
+	}
 	g_mime_object_set_header (GMIME_OBJECT (reply),
 				  "From", from_addr);
 
@@ -590,7 +607,8 @@ notmuch_reply_format_headers_only(void *ctx,
 				  notmuch_config_t *config,
 				  notmuch_query_t *query,
 				  unused (notmuch_show_params_t *params),
-				  notmuch_bool_t reply_all)
+				  notmuch_bool_t reply_all,
+				  unused (int from_select))
 {
     GMimeMessage *reply;
     notmuch_messages_t *messages;
@@ -657,10 +675,11 @@ notmuch_reply_command (void *ctx, int argc, char *argv[])
     notmuch_query_t *query;
     char *query_string;
     int opt_index, ret = 0;
-    int (*reply_format_func)(void *ctx, notmuch_config_t *config, notmuch_query_t *query, notmuch_show_params_t *params, notmuch_bool_t reply_all);
+    int (*reply_format_func)(void *ctx, notmuch_config_t *config, notmuch_query_t *query, notmuch_show_params_t *params, notmuch_bool_t reply_all, int from_select);
     notmuch_show_params_t params = { .part = -1 };
     int format = FORMAT_DEFAULT;
     int reply_all = TRUE;
+    int from_select = FROM_FALLBACK_ALL;
     notmuch_bool_t decrypt = FALSE;
 
     notmuch_opt_desc_t options[] = {
@@ -672,6 +691,14 @@ notmuch_reply_command (void *ctx, int argc, char *argv[])
 	  (notmuch_keyword_t []){ { "all", TRUE },
 				  { "sender", FALSE },
 				  { 0, 0 } } },
+	{ NOTMUCH_OPT_KEYWORD, &from_select, "from", 'F',
+	  (notmuch_keyword_t []){ { "default", FROM_FALLBACK_ALL },
+				  { "fallback-all", FROM_FALLBACK_ALL },
+				  { "fallback-received", FROM_FALLBACK_RECEIVED },
+				  { "fallback-none", FROM_FALLBACK_NONE },
+				  { "none", FROM_NONE },
+				  { "primary", FROM_PRIMARY },
+				  { 0, 0 } } },
 	{ NOTMUCH_OPT_BOOLEAN, &decrypt, "decrypt", 'd', 0 },
 	{ 0, 0, 0, 0, 0 }
     };
@@ -732,7 +759,7 @@ notmuch_reply_command (void *ctx, int argc, char *argv[])
 	return 1;
     }
 
-    if (reply_format_func (ctx, config, query, &params, reply_all) != 0)
+    if (reply_format_func (ctx, config, query, &params, reply_all, from_select) != 0)
 	return 1;
 
     notmuch_query_destroy (query);
-- 
1.7.2.3