IMAP SEARCH PARTIAL: use previous params/results to inform next one

cyrusimap · Dec 6, 2023 · c892385 · c892385
1 parent 9bd2257
commit c892385
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Showing 5 changed files with 49 additions and 19 deletions.
diff --git a/cassandane/Cassandane/Cyrus/Search.pm b/cassandane/Cassandane/Cyrus/Search.pm
@@ -818,6 +818,19 @@ sub test_partial
     $self->assert_str_equals('3:4', $results[0][2][0]);
     $self->assert_str_equals('4:5', $results[0][2][1]);
 
+    # flag the last message
+    $imaptalk->store('10', '+FLAGS', '(\\flagged)');
+    $self->assert_str_equals('ok', $imaptalk->get_last_completion_response());
+
+    # search and return next 2 messages
+    @results = ();
+    $res = $imaptalk->_imap_cmd('SEARCH', 0, \%handlers,
+                                'RETURN', '(PARTIAL 5:6)', 'UNDELETED');
+    $self->assert_str_equals('ok', $imaptalk->get_last_completion_response());
+    $self->assert_str_equals('PARTIAL', $results[0][1]);
+    $self->assert_str_equals('5:6', $results[0][2][0]);
+    $self->assert_str_equals('7:8', $results[0][2][1]);
+
     # search and return last 2 messages
     @results = ();
     $res = $imaptalk->_imap_cmd('SEARCH', 0, \%handlers,

diff --git a/imap/index.c b/imap/index.c
@@ -2203,6 +2203,12 @@ EXPORTED int index_search(struct index_state *state,
                         sign, searchargs->partial.low,
                         sign, searchargs->partial.high,
                         seqstr ? seqstr : "NIL");
+
+            /* Save search params/results for subsequent PARTIAL */
+            memcpy(&state->last_search.partial,
+                   &searchargs->partial, sizeof(range_t));
+            state->last_search.last_match = folder->esearch.last_match;
+            state->last_search.highestmodseq = state->highestmodseq;
         }
 
         free(seqstr);

diff --git a/imap/index.h b/imap/index.h
@@ -138,7 +138,12 @@ struct index_state {
     int want_expunged;
     unsigned num_expunged;
     message_t *m;
-    seqset_t *searchres; /* RFC 5182 search results */
+    seqset_t *searchres; /* RFC 5182 SEARCH results */
+    struct {
+        range_t partial;
+        uint32_t last_match;
+        uint64_t highestmodseq; /* of the folder */
+    } last_search;       /* RFC 9394 last SEARCH PARTIAL (for optimization) */
 };
 
 struct copyargs {

diff --git a/imap/search_query.c b/imap/search_query.c
@@ -496,10 +496,10 @@ static int _subquery_run_one_folder(search_query_t *query,
 {
     struct searchargs *searchargs = query->searchargs;
     struct index_state *state = NULL;
-    unsigned msgno;
+    unsigned msgno = 1;
     unsigned nmsgs = 0;
     unsigned *msgno_list = NULL;
-    int inc, do_all = 1;
+    int inc = 1, do_all = 1;
     int r = 0;
 
     if (query->sortcrit && query->verbose) {
@@ -540,20 +540,26 @@ static int _subquery_run_one_folder(search_query_t *query,
 
     case SEARCH_RETURN_PARTIAL:
         do_all = 0;
+
+        /* Reverse the iterator? */
+        if (searchargs->partial.is_last) {
+            msgno = state->exists;
+            inc = -1;
+        }
+
+        /* Can we use the last PARTIAL params/results to inform this one? */
+        if (query->state->last_search.highestmodseq == state->highestmodseq &&
+            query->state->last_search.partial.is_last == searchargs->partial.is_last &&
+            query->state->last_search.partial.high < searchargs->partial.low) {
+
+            msgno = query->state->last_search.last_match + inc;
+            nmsgs = query->state->last_search.partial.high;
+        }
         break;
 
     default:
         if (!searchargs->partial.high) searchargs->partial.high = ULONG_MAX;
-        break;    
-    }
-
-    if (searchargs->partial.is_last) {
-        msgno = state->exists;
-        inc = -1;
-    }
-    else {
-        msgno = 1;
-        inc = 1;
+        break;
     }
 
     /* One pass through the folder's message list */
@@ -619,23 +625,22 @@ static int _subquery_run_one_folder(search_query_t *query,
         }
 
         /* don't add anything outside of the partial range */
-        if (folder->esearch.all_count < searchargs->partial.low) continue;
-        if (folder->esearch.all_count > searchargs->partial.high) continue;
+        if (++nmsgs < searchargs->partial.low) continue;
+        if (nmsgs > searchargs->partial.high) continue;
 
         folder_add_uid(&folder->uids, im->uid);
         folder_add_modseq(folder, im->modseq);
+        folder->esearch.last_match = msgno;
 
         if (query->sortcrit)
-            msgno_list[nmsgs] = msgno;
+            msgno_list[folder->esearch.uid_count] = msgno;
 
-        ++nmsgs;
+        folder->esearch.uid_count++;
     }
 
     if (query->sortcrit && nmsgs)
         query_load_msgdata(query, folder, state, msgno_list, nmsgs);
 
-    if (folder) folder->esearch.uid_count = nmsgs;
-
 out:
     if (state) query_end_index(query, &state);
     free(msgno_list);

diff --git a/imap/search_query.h b/imap/search_query.h
@@ -74,6 +74,7 @@ struct search_folder {
     struct {
         /* RFC 4731 result items */
         bitvector_t all_uids;    /* for SAVE + PARTIAL + COUNT */
+        uint32_t last_match;     /* msgno of last match (for next PARTIAL) */
         uint32_t all_count;      /* for COUNT */
         uint32_t uid_count;      /* of returned messages */
         uint32_t min_uid;        /* for MIN */