[Spice-devel] [PATCH spice-server v2] image-encoders: Initialize Zlib lazily

[Frediano Ziglio]

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 at redhat.com>
---
 server/image-encoders.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

Changes since v1:
- log a warning if zlib encoding cannot be initialized

diff --git a/server/image-encoders.c b/server/image-encoders.c
index 88073a3e..f35621ff 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) {
+        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) {
+        enc->zlib = zlib_encoder_create(&enc->zlib_data.usr, ZLIB_DEFAULT_COMPRESSION_LEVEL);
+        if (!enc->zlib) {
+            g_warning("create zlib encoder failed");
+            goto glz;
+        }
+    }
     stat_start_time_init(&start_time, &enc->shared_data->zlib_glz_stat);
     zlib_data = &enc->zlib_data;
 
-- 
2.20.1