image-encoders: Initialize Zlib lazily

Zlib structure take up more than 1MB and it is rarely used nowadays
as it is not much effective.
Initialise it only when necessary saving some memory in the normal
case.

Signed-off-by: Frediano Ziglio <fziglio@redhat.com>
Acked-by: Christophe Fergeau <cfergeau@redhat.com>

1 files changed, 11 insertions, 8 deletions

diff --git a/server/image-encoders.c b/server/image-encoders.c
index 88073a3e..5a87df31 100644
--- a/server/image-encoders.c
+++ b/server/image-encoders.c
@@ -451,12 +451,6 @@ static void image_encoders_init_zlib(ImageEncoders *enc)
 {
     enc->zlib_data.usr.more_space = zlib_usr_more_space;
     enc->zlib_data.usr.more_input = zlib_usr_more_input;
-
-    enc->zlib = zlib_encoder_create(&enc->zlib_data.usr, ZLIB_DEFAULT_COMPRESSION_LEVEL);
-
-    if (!enc->zlib) {
-        spice_critical("create zlib encoder failed");
-    }
 }
 
 void image_encoders_init(ImageEncoders *enc, ImageEncoderSharedData *shared_data)
@@ -494,8 +488,10 @@ void image_encoders_free(ImageEncoders *enc)
     lz4_encoder_destroy(enc->lz4);
     enc->lz4 = NULL;
 #endif
-    zlib_encoder_destroy(enc->zlib);
-    enc->zlib = NULL;
+    if (enc->zlib != NULL) {
+        zlib_encoder_destroy(enc->zlib);
+        enc->zlib = NULL;
+    }
     pthread_mutex_destroy(&enc->glz_drawables_inst_to_free_lock);
 }
 
@@ -1261,6 +1257,13 @@ bool image_encoders_compress_glz(ImageEncoders *enc,
     if (!enable_zlib_glz_wrap || (glz_size < MIN_GLZ_SIZE_FOR_ZLIB)) {
         goto glz;
     }
+    if (enc->zlib == NULL) {
+        enc->zlib = zlib_encoder_create(&enc->zlib_data.usr, ZLIB_DEFAULT_COMPRESSION_LEVEL);
+        if (enc->zlib == NULL) {
+            g_warning("creating zlib encoder failed");
+            goto glz;
+        }
+    }
     stat_start_time_init(&start_time, &enc->shared_data->zlib_glz_stat);
     zlib_data = &enc->zlib_data;