journal: add LZ4 as optional compressor

Add liblz4 as an optional dependency when requested with --enable-lz4,
and use it in preference to liblzma for journal blob and coredump
compression. To retain backwards compatibility, XZ is used to
decompress old blobs.

Things will function correctly only with lz4-119.

Based on the benchmarks found on the web, lz4 seems to be the best
choice for "quick" compressors atm.

For pkg-config status, see http://code.google.com/p/lz4/issues/detail?id=135.

1 files changed, 16 insertions, 20 deletions

diff --git a/src/journal/sd-journal.c b/src/journal/sd-journal.c
index ca805f83fe..96ba2bd11e 100644
--- a/src/journal/sd-journal.c
+++ b/src/journal/sd-journal.c
@@ -1995,28 +1995,24 @@ _public_ int sd_journal_get_data(sd_journal *j, const char *field, const void **
 
                 l = le64toh(o->object.size) - offsetof(Object, data.payload);
 
-                if (o->object.flags & OBJECT_COMPRESSED) {
+                if ((o->object.flags & OBJECT_COMPRESSION_MASK) &&
+                    decompress_startswith(o->object.flags & OBJECT_COMPRESSION_MASK,
+                                          o->data.payload, l,
+                                          &f->compress_buffer, &f->compress_buffer_size,
+                                          field, field_length, '=')) {
 
-#ifdef HAVE_XZ
-                        if (uncompress_startswith(o->data.payload, l,
-                                                  &f->compress_buffer, &f->compress_buffer_size,
-                                                  field, field_length, '=')) {
-
-                                uint64_t rsize;
+                        uint64_t rsize;
 
-                                if (!uncompress_blob(o->data.payload, l,
-                                                     &f->compress_buffer, &f->compress_buffer_size, &rsize,
-                                                     j->data_threshold))
-                                        return -EBADMSG;
+                        r = decompress_blob_xz(o->data.payload, l,
+                                               &f->compress_buffer, &f->compress_buffer_size, &rsize,
+                                               j->data_threshold);
+                        if (r < 0)
+                                return r;
 
-                                *data = f->compress_buffer;
-                                *size = (size_t) rsize;
+                        *data = f->compress_buffer;
+                        *size = (size_t) rsize;
 
-                                return 0;
-                        }
-#else
-                        return -EPROTONOSUPPORT;
-#endif
+                        return 0;
 
                 } else if (l >= field_length+1 &&
                            memcmp(o->data.payload, field, field_length) == 0 &&
@@ -2052,11 +2048,11 @@ static int return_data(sd_journal *j, JournalFile *f, Object *o, const void **da
         if ((uint64_t) t != l)
                 return -E2BIG;
 
-        if (o->object.flags & OBJECT_COMPRESSED) {
+        if (o->object.flags & OBJECT_COMPRESSED_XZ) {
 #ifdef HAVE_XZ
                 uint64_t rsize;
 
-                if (!uncompress_blob(o->data.payload, l, &f->compress_buffer, &f->compress_buffer_size, &rsize, j->data_threshold))
+                if (!decompress_blob_xz(o->data.payload, l, &f->compress_buffer, &f->compress_buffer_size, &rsize, j->data_threshold))
                         return -EBADMSG;
 
                 *data = f->compress_buffer;