journal: implement seek to head/tail

3 files changed, 61 insertions, 21 deletions

diff --git a/src/journal/journalctl.c b/src/journal/journalctl.c
index 3475b9d43c..3e5ee1af96 100644
--- a/src/journal/journalctl.c
+++ b/src/journal/journalctl.c
@@ -54,7 +54,8 @@ int main(int argc, char *argv[]) {
                 }
         }
 
-        SD_JOURNAL_FOREACH(j) {
+        SD_JOURNAL_FOREACH_BEGIN(j) {
+
                 const void *data;
                 size_t length;
                 char *cursor;
@@ -76,9 +77,10 @@ int main(int argc, char *argv[]) {
                        (unsigned long long) realtime,
                        (unsigned long long) monotonic);
 
-                SD_JOURNAL_FOREACH_FIELD(j, data, length)
+                SD_JOURNAL_FOREACH_DATA(j, data, length)
                         printf("\t%.*s\n", (int) length, (const char*) data);
-        }
+
+        } SD_JOURNAL_FOREACH_END(j);
 
 finish:
         if (j)
diff --git a/src/journal/sd-journal.c b/src/journal/sd-journal.c
index 985e3210ce..6a68275e9e 100644
--- a/src/journal/sd-journal.c
+++ b/src/journal/sd-journal.c
@@ -585,7 +585,7 @@ int sd_journal_get_monotonic_usec(sd_journal *j, uint64_t *ret) {
 
 }
 
-int sd_journal_get_field(sd_journal *j, const char *field, const void **data, size_t *size) {
+int sd_journal_get_data(sd_journal *j, const char *field, const void **data, size_t *size) {
         JournalFile *f;
         uint64_t i, n;
         size_t field_length;
@@ -652,7 +652,7 @@ int sd_journal_get_field(sd_journal *j, const char *field, const void **data, si
         return 0;
 }
 
-int sd_journal_iterate_fields(sd_journal *j, const void **data, size_t *size) {
+int sd_journal_enumerate_data(sd_journal *j, const void **data, size_t *size) {
         JournalFile *f;
         uint64_t p, l, n, h;
         size_t t;
@@ -702,12 +702,31 @@ int sd_journal_iterate_fields(sd_journal *j, const void **data, size_t *size) {
         return 1;
 }
 
-int sd_journal_seek_head(sd_journal *j) {
+void sd_journal_start_data(sd_journal *j) {
         assert(j);
-        return -EINVAL;
+
+        j->current_field = 0;
 }
 
-int sd_journal_seek_tail(sd_journal *j) {
+static int real_journal_seek_head(sd_journal *j, direction_t direction) {
+        Iterator i;
+        JournalFile *f;
+
         assert(j);
-        return -EINVAL;
+
+        j->current_file = NULL;
+        j->current_field = 0;
+
+        HASHMAP_FOREACH(f, j->files, i)
+                f->current_offset = 0;
+
+        return real_journal_next(j, direction);
+}
+
+int sd_journal_seek_head(sd_journal *j) {
+        return real_journal_seek_head(j, DIRECTION_DOWN);
+}
+
+int sd_journal_seek_tail(sd_journal *j) {
+        return real_journal_seek_head(j, DIRECTION_UP);
 }
diff --git a/src/journal/sd-journal.h b/src/journal/sd-journal.h
index 6b451b5765..bf6673453d 100644
--- a/src/journal/sd-journal.h
+++ b/src/journal/sd-journal.h
@@ -49,8 +49,9 @@ int sd_journal_next(sd_journal *j);
 
 int sd_journal_get_realtime_usec(sd_journal *j, uint64_t *ret);
 int sd_journal_get_monotonic_usec(sd_journal *j, uint64_t *ret);
-int sd_journal_get_field(sd_journal *j, const char *field, const void **data, size_t *l);
-int sd_journal_iterate_fields(sd_journal *j, const void **data, size_t *l);
+int sd_journal_get_data(sd_journal *j, const char *field, const void **data, size_t *l);
+int sd_journal_enumerate_data(sd_journal *j, const void **data, size_t *l);
+void sd_journal_start_data(sd_journal *j);
 
 int sd_journal_add_match(sd_journal *j, const void *data, size_t size);
 void sd_journal_flush_matches(sd_journal *j);
@@ -58,13 +59,16 @@ void sd_journal_flush_matches(sd_journal *j);
 int sd_journal_seek_head(sd_journal *j);
 int sd_journal_seek_tail(sd_journal *j);
 
-int sd_journal_seek_monotonic_usec(sd_journal *j, uint64_t usec);
-int sd_journal_seek_realtime_usec(sd_journal *j, uint64_t usec);
+int sd_journal_seek_monotonic_usec(sd_journal *j, uint64_t usec);  /* missing */
+int sd_journal_seek_realtime_usec(sd_journal *j, uint64_t usec);   /* missing */
 
 int sd_journal_get_cursor(sd_journal *j, char **cursor);
-int sd_journal_set_cursor(sd_journal *j, const char *cursor);
+int sd_journal_set_cursor(sd_journal *j, const char *cursor);      /* missing */
 
-int sd_journal_get_fd(sd_journal *j);
+int sd_journal_unique_seek(sd_journal *j, const char *field);      /* missing */
+int sd_journal_unique_enumerate(sd_journal *j, const void **data, size_t *l); /* missing */
+
+int sd_journal_get_fd(sd_journal *j);                              /* missing */
 
 enum {
         SD_JOURNAL_NOP,
@@ -74,13 +78,28 @@ enum {
 
 int sd_journal_process(sd_journal *j);
 
-#define SD_JOURNAL_FOREACH(j)                   \
-        while (sd_journal_next(j) > 0)
+#define SD_JOURNAL_FOREACH_BEGIN(j)             \
+        if (sd_journal_seek_head(j) > 0) do {
+
+#define SD_JOURNAL_FOREACH_END(j)               \
+        } while (sd_journal_next(j) > 0)
+
+#define SD_JOURNAL_FOREACH_CONTINUE(j)          \
+        do {
+
+#define SD_JOURNAL_FOREACH_BACKWARDS_BEGIN(j)   \
+        if (sd_journal_seek_tail(j) > 0) do {
+
+#define SD_JOURNAL_FOREACH_BACKWARDS_END(j)     \
+        } while (sd_journal_previous(j) > 0)
+
+#define SD_JOURNAL_FOREACH_BACKWARDS_CONTINUE(j) \
+        do {
 
-#define SD_JOURNAL_FOREACH_BACKWARDS(j)         \
-        while (sd_journal_previous(j) > 0)
+#define SD_JOURNAL_FOREACH_DATA(j, data, l)                             \
+        for (sd_journal_start_data(j); sd_journal_enumerate_data((j), &(data), &(l)) > 0; )
 
-#define SD_JOURNAL_FOREACH_FIELD(j, data, l)                            \
-        while (sd_journal_iterate_fields((j), &(data), &(l)) > 0)
+#define SD_JOURNAL_FOREACH_UNIQUE(j, data, l)                      \
+        while (sd_journal_enumerate_unique_data((j), &(data), &(l)) > 0)
 
 #endif