journal: compare candidate entries using JournalFiles' locations

When comparing the locations of candidate entries, we can rely on the
location information stored in struct JournalFile.

3 files changed, 54 insertions, 85 deletions

diff --git a/src/journal/journal-file.c b/src/journal/journal-file.c
index 7b9815c69..35f3ea92a 100644
--- a/src/journal/journal-file.c
+++ b/src/journal/journal-file.c
@@ -1949,6 +1949,58 @@ void journal_file_save_location(JournalFile *f, direction_t direction, Object *o
         f->current_xor_hash = le64toh(o->entry.xor_hash);
 }
 
+int journal_file_compare_locations(JournalFile *af, JournalFile *bf) {
+        assert(af);
+        assert(bf);
+        assert(af->location_type == LOCATION_SEEK);
+        assert(bf->location_type == LOCATION_SEEK);
+
+        /* If contents and timestamps match, these entries are
+         * identical, even if the seqnum does not match */
+        if (sd_id128_equal(af->current_boot_id, bf->current_boot_id) &&
+            af->current_monotonic == bf->current_monotonic &&
+            af->current_realtime == bf->current_realtime &&
+            af->current_xor_hash == bf->current_xor_hash)
+                return 0;
+
+        if (sd_id128_equal(af->header->seqnum_id, bf->header->seqnum_id)) {
+
+                /* If this is from the same seqnum source, compare
+                 * seqnums */
+                if (af->current_seqnum < bf->current_seqnum)
+                        return -1;
+                if (af->current_seqnum > bf->current_seqnum)
+                        return 1;
+
+                /* Wow! This is weird, different data but the same
+                 * seqnums? Something is borked, but let's make the
+                 * best of it and compare by time. */
+        }
+
+        if (sd_id128_equal(af->current_boot_id, bf->current_boot_id)) {
+
+                /* If the boot id matches, compare monotonic time */
+                if (af->current_monotonic < bf->current_monotonic)
+                        return -1;
+                if (af->current_monotonic > bf->current_monotonic)
+                        return 1;
+        }
+
+        /* Otherwise, compare UTC time */
+        if (af->current_realtime < bf->current_realtime)
+                return -1;
+        if (af->current_realtime > bf->current_realtime)
+                return 1;
+
+        /* Finally, compare by contents */
+        if (af->current_xor_hash < bf->current_xor_hash)
+                return -1;
+        if (af->current_xor_hash > bf->current_xor_hash)
+                return 1;
+
+        return 0;
+}
+
 int journal_file_next_entry(
                 JournalFile *f,
                 Object *o, uint64_t p,
diff --git a/src/journal/journal-file.h b/src/journal/journal-file.h
index 2bdfff782..808417619 100644
--- a/src/journal/journal-file.h
+++ b/src/journal/journal-file.h
@@ -197,6 +197,7 @@ int journal_file_find_field_object_with_hash(JournalFile *f, const void *field,
 
 void journal_file_reset_location(JournalFile *f);
 void journal_file_save_location(JournalFile *f, direction_t direction, Object *o, uint64_t offset);
+int journal_file_compare_locations(JournalFile *af, JournalFile *bf);
 int journal_file_next_entry(JournalFile *f, Object *o, uint64_t p, direction_t direction, Object **ret, uint64_t *offset);
 
 int journal_file_next_entry_for_data(JournalFile *f, Object *o, uint64_t p, uint64_t data_offset, direction_t direction, Object **ret, uint64_t *offset);
diff --git a/src/journal/sd-journal.c b/src/journal/sd-journal.c
index 5a00cb0c9..7ca0f839c 100644
--- a/src/journal/sd-journal.c
+++ b/src/journal/sd-journal.c
@@ -412,90 +412,6 @@ _public_ void sd_journal_flush_matches(sd_journal *j) {
         detach_location(j);
 }
 
-static int compare_entry_order(JournalFile *af, Object *_ao,
-                               JournalFile *bf, uint64_t bp) {
-
-        uint64_t a, b;
-        Object *ao, *bo;
-        int r;
-
-        assert(af);
-        assert(bf);
-        assert(_ao);
-
-        /* The mmap cache might invalidate the object from the first
-         * file if we look at the one from the second file. Hence
-         * temporarily copy the header of the first one, and look at
-         * that only. */
-        ao = alloca(offsetof(EntryObject, items));
-        memcpy(ao, _ao, offsetof(EntryObject, items));
-
-        r = journal_file_move_to_object(bf, OBJECT_ENTRY, bp, &bo);
-        if (r < 0)
-                return strcmp(af->path, bf->path);
-
-        /* We operate on two different files here, hence we can access
-         * two objects at the same time, which we normally can't.
-         *
-         * If contents and timestamps match, these entries are
-         * identical, even if the seqnum does not match */
-
-        if (sd_id128_equal(ao->entry.boot_id, bo->entry.boot_id) &&
-            ao->entry.monotonic == bo->entry.monotonic &&
-            ao->entry.realtime == bo->entry.realtime &&
-            ao->entry.xor_hash == bo->entry.xor_hash)
-                return 0;
-
-        if (sd_id128_equal(af->header->seqnum_id, bf->header->seqnum_id)) {
-
-                /* If this is from the same seqnum source, compare
-                 * seqnums */
-                a = le64toh(ao->entry.seqnum);
-                b = le64toh(bo->entry.seqnum);
-
-                if (a < b)
-                        return -1;
-                if (a > b)
-                        return 1;
-
-                /* Wow! This is weird, different data but the same
-                 * seqnums? Something is borked, but let's make the
-                 * best of it and compare by time. */
-        }
-
-        if (sd_id128_equal(ao->entry.boot_id, bo->entry.boot_id)) {
-
-                /* If the boot id matches, compare monotonic time */
-                a = le64toh(ao->entry.monotonic);
-                b = le64toh(bo->entry.monotonic);
-
-                if (a < b)
-                        return -1;
-                if (a > b)
-                        return 1;
-        }
-
-        /* Otherwise, compare UTC time */
-        a = le64toh(ao->entry.realtime);
-        b = le64toh(bo->entry.realtime);
-
-        if (a < b)
-                return -1;
-        if (a > b)
-                return 1;
-
-        /* Finally, compare by contents */
-        a = le64toh(ao->entry.xor_hash);
-        b = le64toh(bo->entry.xor_hash);
-
-        if (a < b)
-                return -1;
-        if (a > b)
-                return 1;
-
-        return 0;
-}
-
 _pure_ static int compare_with_location(JournalFile *af, Object *ao, Location *l) {
         uint64_t a;
 
@@ -898,7 +814,7 @@ static int real_journal_next(sd_journal *j, direction_t direction) {
                 else {
                         int k;
 
-                        k = compare_entry_order(f, o, new_file, new_offset);
+                        k = journal_file_compare_locations(f, new_file);
 
                         found = direction == DIRECTION_DOWN ? k < 0 : k > 0;
                 }