Add logging hooks to mtmd to allow redirection to appropriate log message sinks

common/log.cpp

@@ -416,6 +416,10 @@ void common_log_add(struct common_log * log, enum ggml_log_level level, const ch
     va_end(args);
 }
 
+void common_log_add_v(struct common_log * log, enum ggml_log_level level, const char * fmt, va_list args) {
+    log->add(level, fmt, args);
+}
+
 void common_log_set_file(struct common_log * log, const char * file) {
     log->set_file(file);
 }

common/log.h

@@ -49,6 +49,8 @@ void                common_log_free  (struct common_log * log);
 LOG_ATTRIBUTE_FORMAT(3, 4)
 void common_log_add(struct common_log * log, enum ggml_log_level level, const char * fmt, ...);
 
+void common_log_add_v(struct common_log * log, enum ggml_log_level level, const char * fmt, va_list args);
+
 // defaults: file = NULL, colors = false, prefix = false, timestamps = false
 //
 // regular log output:

ggml/include/ggml.h

@@ -208,6 +208,7 @@
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
+#include <stdarg.h>
 
 #define GGML_FILE_MAGIC   0x67676d6c // "ggml"
 #define GGML_FILE_VERSION 2

tools/mtmd/mtmd-cli.cpp

@@ -266,6 +266,13 @@ static int eval_message(mtmd_cli_context & ctx, common_chat_msg & msg) {
     return 0;
 }
 
+static void mtmd_log_callback(enum ggml_log_level level, const char * fmt, ...) {
+    va_list args;
+    va_start(args, fmt);
+   common_log_add_v(common_log_main(), level, fmt, args);
+    va_end(args);
+}
+
 int main(int argc, char ** argv) {
     ggml_time_init();
 
@@ -277,6 +284,7 @@ int main(int argc, char ** argv) {
     }
 
     common_init();
+    mtmd_set_log_callback(mtmd_log_callback);
 
     if (params.mmproj.path.empty()) {
         show_additional_info(argc, argv);
@@ -285,7 +293,7 @@ int main(int argc, char ** argv) {
     }
 
     mtmd_cli_context ctx(params);
-    LOG("%s: loading model: %s\n", __func__, params.model.path.c_str());
+    LOG_INF("%s: loading model: %s\n", __func__, params.model.path.c_str());
 
     bool is_single_turn = !params.prompt.empty() && !params.image.empty();
 

tools/mtmd/mtmd-helper.cpp

@@ -32,8 +32,24 @@
 #define STB_IMAGE_IMPLEMENTATION
 #include "stb/stb_image.h"
 
-#define LOG_INF(...) fprintf(stdout, __VA_ARGS__)
-#define LOG_ERR(...) fprintf(stderr, __VA_ARGS__)
+static void log_callback_default(enum ggml_log_level level, const char * fmt, ...) {
+    va_list args;
+    va_start(args, fmt);
+    if (level >= GGML_LOG_LEVEL_ERROR) {
+        vfprintf(stderr, fmt, args);
+    } else {
+        vfprintf(stdout, fmt, args);
+    }
+    va_end(args);
+
+}
+static mtmd_log_callback_t log_callback = log_callback_default;
+
+void mtmd_set_log_callback(mtmd_log_callback_t callback) {
+    log_callback = callback;
+}
+#define LOG_INF(...) (*log_callback)(GGML_LOG_LEVEL_INFO, __VA_ARGS__)
+#define LOG_ERR(...) (*log_callback)(GGML_LOG_LEVEL_ERROR, __VA_ARGS__)
 
 size_t mtmd_helper_get_n_tokens(const mtmd_input_chunks * chunks) {
     size_t n_tokens = 0;

tools/mtmd/mtmd-helper.h

@@ -80,6 +80,9 @@ MTMD_API int32_t mtmd_helper_decode_image_chunk(mtmd_context * ctx,
                                                 int32_t n_batch,
                                                 llama_pos * new_n_past);
 
+typedef void (*mtmd_log_callback_t)(enum ggml_log_level level, const char * fmt, ...);                                                
+MTMD_API void mtmd_set_log_callback(mtmd_log_callback_t callback);
+
 #ifdef __cplusplus
 } // extern "C"
 #endif