[PATCH Draft 2 8/9] notmuch-restore: auto detect format of backup

[David Bremner]

From: David Bremner <brem...@debian.org>

The simple heuristic relies on the fact that '(' is not part of the
character set used by hex-escape. Since hex-escape is designed to be
OK for pathnames (and shells), this seems like a reasonable
assumption.

In principle the --format argument to notmuch-restore is notmuch
needed at this point, but it adds literally 5 lines of argument
description, so I left it.
---
 dump-restore-private.h |    5 +++--
 notmuch-restore.c      |   45 ++++++++++++++++++++++++++++++++-------------
 2 files changed, 35 insertions(+), 15 deletions(-)

diff --git a/dump-restore-private.h b/dump-restore-private.h
index 34a5022..67795e5 100644
--- a/dump-restore-private.h
+++ b/dump-restore-private.h
@@ -5,8 +5,9 @@
 #include "command-line-arguments.h"

 typedef enum dump_formats {
-    DUMP_FORMAT_SUP,
-    DUMP_FORMAT_NOTMUCH
+    DUMP_FORMAT_AUTO,
+    DUMP_FORMAT_NOTMUCH,
+    DUMP_FORMAT_SUP
 } dump_format_t;

 #endif
diff --git a/notmuch-restore.c b/notmuch-restore.c
index f618b47..340f31f 100644
--- a/notmuch-restore.c
+++ b/notmuch-restore.c
@@ -36,7 +36,7 @@ notmuch_restore_command (unused (void *ctx), int argc, char 
*argv[])
     regex_t regex;
     int rerr;
     int opt_index;
-    int input_format = DUMP_FORMAT_SUP;
+    int input_format = DUMP_FORMAT_AUTO;

     config = notmuch_config_open (ctx, NULL, NULL);
     if (config == NULL)
@@ -50,7 +50,11 @@ notmuch_restore_command (unused (void *ctx), int argc, char 
*argv[])
     synchronize_flags = notmuch_config_get_maildir_synchronize_flags (config);

     notmuch_opt_desc_t options[] = {
-       FORMAT_DESC (input_format),
+       { NOTMUCH_OPT_KEYWORD, &input_format, "format", 'f',
+         (notmuch_keyword_t []){ { "auto", DUMP_FORMAT_AUTO },
+                                 { "notmuch", DUMP_FORMAT_NOTMUCH },
+                                 { "sup", DUMP_FORMAT_SUP },
+                                 {0, 0} } },
        { NOTMUCH_OPT_POSITION, &input_file_name, 0, 0, 0 },
        { NOTMUCH_OPT_BOOLEAN,  &accumulate, "accumulate", 'a', 0 },
        { 0, 0, 0, 0, 0 }
@@ -80,17 +84,6 @@ notmuch_restore_command (unused (void *ctx), int argc, char 
*argv[])
        return 1;
     }

-    /* Dump output is one line per message. We match a sequence of
-     * non-space characters for the message-id, then one or more
-     * spaces, then a list of space-separated tags as a sequence of
-     * characters within literal '(' and ')'. */
-    if (input_format == DUMP_FORMAT_SUP) {
-       if ( xregcomp (&regex,
-                      "^([^ ]+) \\(([^)]*)\\)$",
-                      REG_EXTENDED) )
-           INTERNAL_ERROR("compile time constant regex failed.");
-    }
-

     /* These are out here to re-use the buffers with hex_decode */

@@ -98,6 +91,7 @@ notmuch_restore_command (unused (void *ctx), int argc, char 
*argv[])
     size_t message_id_size = 0;
     char *tag = NULL;
     size_t tag_size = 0;
+    notmuch_bool_t first_line = TRUE;

     while ((line_len = getline (&line, &line_size, input)) != -1) {
        regmatch_t match[3];
@@ -109,6 +103,30 @@ notmuch_restore_command (unused (void *ctx), int argc, 
char *argv[])
        char *db_tags_str;

        chomp_newline (line);
+       if (first_line && input_format == DUMP_FORMAT_AUTO) {
+           char *p;
+
+           for (p = line; *p; p++) {
+               if (*p == '(')
+                   input_format = DUMP_FORMAT_SUP;
+           }
+
+           if (input_format == DUMP_FORMAT_AUTO)
+               input_format = DUMP_FORMAT_NOTMUCH;
+
+       }
+
+       /* sup dump output is one line per message. We match a
+        * sequence of non-space characters for the message-id, then
+        * one or more spaces, then a list of space-separated tags as
+        * a sequence of characters within literal '(' and ')'. */
+       if (first_line && input_format == DUMP_FORMAT_SUP) {
+           if ( xregcomp (&regex,
+                          "^([^ ]+) \\(([^)]*)\\)$",
+                          REG_EXTENDED) )
+               INTERNAL_ERROR("compile time constant regex failed.");
+       }
+

        /* Silently ignore blank lines */

@@ -141,6 +159,7 @@ notmuch_restore_command (unused (void *ctx), int argc, char 
*argv[])
            file_tags = xstrdup (p);
        }

+       first_line = FALSE;

        status = notmuch_database_find_message (notmuch, message_id, &message);
        if (status || message == NULL) {
-- 
1.7.7.3