feat: expose the loaded model version name through the public API (#1962)

include/stable-diffusion.h

@@ -493,6 +493,9 @@ SD_API void free_sd_audio(sd_audio_t* audio);
 SD_API void sd_sample_params_init(sd_sample_params_t* sample_params);
 SD_API char* sd_sample_params_to_str(const sd_sample_params_t* sample_params);
 
+// Requires a loaded context; returns a static string owned by the library, or "Unknown".
+SD_API const char* sd_get_model_version_name(const sd_ctx_t* sd_ctx);
+
 SD_API enum sample_method_t sd_get_default_sample_method(const sd_ctx_t* sd_ctx);
 SD_API enum scheduler_t sd_get_default_scheduler(const sd_ctx_t* sd_ctx, enum sample_method_t sample_method);
 

src/pipeline/diffusion_engine.cpp

@@ -99,6 +99,9 @@ const char* model_version_to_str[] = {
     "ESRGAN",
 };
 
+static_assert(VERSION_COUNT == sizeof(model_version_to_str) / sizeof(model_version_to_str[0]),
+              "\nnumber of elements in model_version_to_str[] != VERSION_COUNT");
+
 void calculate_alphas_cumprod(float* alphas_cumprod,
                               float linear_start = 0.00085f,
                               float linear_end   = 0.0120f,

src/stable-diffusion.cpp

@@ -695,6 +695,13 @@ SD_API bool sd_ctx_has_control_net(const sd_ctx_t* sd_ctx) {
     return sd_ctx->sd->control_net != nullptr;
 }
 
+const char* sd_get_model_version_name(const sd_ctx_t* sd_ctx) {
+    if (sd_ctx == nullptr || sd_ctx->sd == nullptr || sd_ctx->sd->version >= VERSION_COUNT) {
+        return "Unknown";
+    }
+    return model_version_to_str[sd_ctx->sd->version];
+}
+
 enum sample_method_t sd_get_default_sample_method(const sd_ctx_t* sd_ctx) {
     return sd::pipeline::default_sample_method(sd_ctx != nullptr ? sd_ctx->sd : nullptr);
 }