mesa: fix empty program log length

In case we have empty log (""), we should return 0. This fixes
Khronos WebGL conformance test 'program-infolog'.

From OpenGL ES 3.1 (and OpenGL 4.5 Core) spec:
   "If pname is INFO_LOG_LENGTH , the length of the info log, including
    a null terminator, is returned. If there is no info log, zero is
    returned."

v2: apply same fix for get_shaderiv and _mesa_GetProgramPipelineiv (Ian)

Signed-off-by: Tapani Pälli <[email protected]>
Reviewed-by: Iago Toral Quiroga <[email protected]> (v1)
Reviewed-by: Ian Romanick <[email protected]>
Reviewed-by: Nicolai Hähnle <[email protected]>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97321
Cc: "13.0" <[email protected]>

1 files changed, 4 insertions, 2 deletions

diff --git a/src/mesa/main/shaderapi.c b/src/mesa/main/shaderapi.c
index 627bc732183..cedcfa3a04c 100644
--- a/src/mesa/main/shaderapi.c
+++ b/src/mesa/main/shaderapi.c
@@ -642,7 +642,8 @@ get_programiv(struct gl_context *ctx, GLuint program, GLenum pname,
       *params = shProg->Validated;
       return;
    case GL_INFO_LOG_LENGTH:
-      *params = shProg->InfoLog ? strlen(shProg->InfoLog) + 1 : 0;
+      *params = (shProg->InfoLog && shProg->InfoLog[0] != '\0') ?
+         strlen(shProg->InfoLog) + 1 : 0;
       return;
    case GL_ATTACHED_SHADERS:
       *params = shProg->NumShaders;
@@ -890,7 +891,8 @@ get_shaderiv(struct gl_context *ctx, GLuint name, GLenum pname, GLint *params)
       *params = shader->CompileStatus;
       break;
    case GL_INFO_LOG_LENGTH:
-      *params = shader->InfoLog ? strlen(shader->InfoLog) + 1 : 0;
+      *params = (shader->InfoLog && shader->InfoLog[0] != '\0') ?
+         strlen(shader->InfoLog) + 1 : 0;
       break;
    case GL_SHADER_SOURCE_LENGTH:
       *params = shader->Source ? strlen((char *) shader->Source) + 1 : 0;