[WIP2 03/12] lib: API to retrieve database revision and UUID

diff --git a/e6/81748f59f36071895a5084650eac9c49864b14 b/e6/81748f59f36071895a5084650eac9c49864b14
new file mode 100644 (file)
index 0000000..08488bb
--- /dev/null
+++ b/e6/81748f59f36071895a5084650eac9c49864b14
@@ -0,0 +1,177 @@
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+From: David Bremner <david@tethera.net>\r
+To: notmuch@notmuchmail.org\r
+Subject: [WIP2 03/12] lib: API to retrieve database revision and UUID\r
+Date: Mon,  6 Apr 2015 07:59:05 +0900\r
+Message-Id: <1428274754-1698-4-git-send-email-david@tethera.net>\r
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+References: <1428274754-1698-1-git-send-email-david@tethera.net>\r
+Cc: Austin Clements <aclements@csail.mit.edu>\r
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+\r
+From: Austin Clements <aclements@csail.mit.edu>\r
+\r
+This exposes the committed database revision to library users along\r
+with a UUID that can be used to detect when revision numbers are no\r
+longer comparable (e.g., because the database has been replaced).\r
+---\r
+ lib/database-private.h         |  1 +\r
+ lib/database.cc                | 11 +++++++++++\r
+ lib/notmuch.h                  | 18 ++++++++++++++++++\r
+ test/T570-revision-tracking.sh | 37 +++++++++++++++++++++++++++++++++++++\r
+ 4 files changed, 67 insertions(+)\r
+ create mode 100755 test/T570-revision-tracking.sh\r
+\r
+diff --git a/lib/database-private.h b/lib/database-private.h\r
+index 5c5a2bb..4e93257 100644\r
+--- a/lib/database-private.h\r
++++ b/lib/database-private.h\r
+@@ -170,6 +170,7 @@ struct _notmuch_database {\r
+      * under a higher revision number, which can be generated with\r
+      * notmuch_database_new_revision. */\r
+     unsigned long revision;\r
++    const char *uuid;\r
+ \r
+     Xapian::QueryParser *query_parser;\r
+     Xapian::TermGenerator *term_gen;\r
+diff --git a/lib/database.cc b/lib/database.cc\r
+index 4378979..f88bdb3 100644\r
+--- a/lib/database.cc\r
++++ b/lib/database.cc\r
+@@ -978,6 +978,8 @@ notmuch_database_open_verbose (const char *path,\r
+           notmuch->revision = 0;\r
+       else\r
+           notmuch->revision = Xapian::sortable_unserialise (last_mod);\r
++      notmuch->uuid = talloc_strdup (\r
++          notmuch, notmuch->xapian_db->get_uuid ().c_str ());\r
+ \r
+       notmuch->query_parser = new Xapian::QueryParser;\r
+       notmuch->term_gen = new Xapian::TermGenerator;\r
+@@ -1651,6 +1653,15 @@ DONE:\r
+     return NOTMUCH_STATUS_SUCCESS;\r
+ }\r
+ \r
++unsigned long\r
++notmuch_database_get_revision (notmuch_database_t *notmuch,\r
++                              const char **uuid)\r
++{\r
++    if (uuid)\r
++      *uuid = notmuch->uuid;\r
++    return notmuch->revision;\r
++}\r
++\r
+ /* We allow the user to use arbitrarily long paths for directories. But\r
+  * we have a term-length limit. So if we exceed that, we'll use the\r
+  * SHA-1 of the path for the database term.\r
+diff --git a/lib/notmuch.h b/lib/notmuch.h\r
+index 20c4e01..b6be727 100644\r
+--- a/lib/notmuch.h\r
++++ b/lib/notmuch.h\r
+@@ -461,6 +461,24 @@ notmuch_status_t\r
+ notmuch_database_end_atomic (notmuch_database_t *notmuch);\r
+ \r
+ /**\r
++ * Return the committed database revision and UUID.\r
++ *\r
++ * The database revision number increases monotonically with each\r
++ * commit to the database.  Hence, all messages and message changes\r
++ * committed to the database (that is, visible to readers) have a last\r
++ * modification revision <= the committed database revision.  Any\r
++ * messages committed in the future will be assigned a modification\r
++ * revision > the committed database revision.\r
++ *\r
++ * The UUID is a NUL-terminated opaque string that uniquely identifies\r
++ * this database.  Two revision numbers are only comparable if they\r
++ * have the same database UUID.\r
++ */\r
++unsigned long\r
++notmuch_database_get_revision (notmuch_database_t *notmuch,\r
++                              const char **uuid);\r
++\r
++/**\r
+  * Retrieve a directory object from the database for 'path'.\r
+  *\r
+  * Here, 'path' should be a path relative to the path of 'database'\r
+diff --git a/test/T570-revision-tracking.sh b/test/T570-revision-tracking.sh\r
+new file mode 100755\r
+index 0000000..8c12740\r
+--- /dev/null\r
++++ b/test/T570-revision-tracking.sh\r
+@@ -0,0 +1,37 @@\r
++#!/usr/bin/env bash\r
++test_description="database revision tracking"\r
++\r
++. ./test-lib.sh\r
++\r
++add_email_corpus\r
++\r
++test_begin_subtest "notmuch_database_get_revision"\r
++test_C ${MAIL_DIR} <<'EOF'\r
++#include <stdio.h>\r
++#include <string.h>\r
++#include <notmuch.h>\r
++int main (int argc, char** argv)\r
++{\r
++   notmuch_database_t *db;\r
++   notmuch_status_t stat;\r
++   long revision;\r
++   const char *uuid;\r
++\r
++   unsigned long rev;\r
++\r
++   stat = notmuch_database_open (argv[1], NOTMUCH_DATABASE_MODE_READ_ONLY, &db);\r
++   if (stat)\r
++       fputs ("open failed\n", stderr);\r
++   revision = notmuch_database_get_revision (db, &uuid);\r
++   printf("revision=%d\nuuid_len=%d\n", revision, strlen (uuid));\r
++}\r
++EOF\r
++cat <<'EOF' >EXPECTED\r
++== stdout ==\r
++revision=53\r
++uuid_len=36\r
++== stderr ==\r
++EOF\r
++test_expect_equal_file OUTPUT EXPECTED\r
++\r
++test_done\r
+-- \r
+2.1.4\r
+\r