jni: introduce a logging util to filter different logging levels on different build types

examples/llama.android/lib/src/main/cpp/ai_chat.cpp

@@ -6,6 +6,7 @@
 #include <unistd.h>
 #include <sampling.h>
 
+#include "logging.h"
 #include "chat.h"
 #include "common.h"
 #include "llama.h"
@@ -20,16 +21,6 @@ static std::string join(const std::vector<T> &values, const std::string &delim)
     return str.str();
 }
 
-/**
- * Logging utils
- */
-#define TAG "ai-chat"
-#define LOGv(...) __android_log_print(ANDROID_LOG_VERBOSE,  TAG, __VA_ARGS__)
-#define LOGd(...) __android_log_print(ANDROID_LOG_DEBUG,    TAG, __VA_ARGS__)
-#define LOGi(...) __android_log_print(ANDROID_LOG_INFO,     TAG, __VA_ARGS__)
-#define LOGw(...) __android_log_print(ANDROID_LOG_WARN,     TAG, __VA_ARGS__)
-#define LOGe(...) __android_log_print(ANDROID_LOG_ERROR,    TAG, __VA_ARGS__)
-
 /**
  * LLama resources: context, model, batch and sampler
  */
@@ -48,33 +39,11 @@ static llama_batch                        g_batch;
 static common_chat_templates_ptr          g_chat_templates;
 static common_sampler                   * g_sampler;
 
-static void log_callback(ggml_log_level level, const char *fmt, void *data) {
-    int priority;
-    switch (level) {
-        case GGML_LOG_LEVEL_ERROR:
-            priority = ANDROID_LOG_ERROR;
-            break;
-        case GGML_LOG_LEVEL_WARN:
-            priority = GGML_LOG_LEVEL_WARN;
-            break;
-        case GGML_LOG_LEVEL_INFO:
-            priority = GGML_LOG_LEVEL_INFO;
-            break;
-        case GGML_LOG_LEVEL_DEBUG:
-            priority = GGML_LOG_LEVEL_DEBUG;
-            break;
-        default:
-            priority = ANDROID_LOG_DEFAULT;
-            break;
-    }
-    __android_log_print(priority, TAG, fmt, data);
-}
-
 extern "C"
 JNIEXPORT void JNICALL
 Java_com_arm_aichat_internal_InferenceEngineImpl_init(JNIEnv *env, jobject /*unused*/, jstring nativeLibDir) {
     // Set llama log handler to Android
-    llama_log_set(log_callback, nullptr);
+    llama_log_set(aichat_android_log_callback, nullptr);
 
     // Loading all CPU backend variants
     const auto *path_to_backend = env->GetStringUTFChars(nativeLibDir, 0);

examples/llama.android/lib/src/main/cpp/logging.h

@@ -0,0 +1,61 @@
+//
+// Created by Han Yin on 10/31/25.
+//
+
+#ifndef AICHAT_LOGGING_H
+#define AICHAT_LOGGING_H
+
+#endif //AICHAT_LOGGING_H
+
+#pragma once
+#include <android/log.h>
+
+#ifndef LOG_TAG
+#define LOG_TAG "ai-chat"
+#endif
+
+#ifndef LOG_MIN_LEVEL
+#if defined(NDEBUG)
+#define LOG_MIN_LEVEL ANDROID_LOG_WARN
+#else
+#define LOG_MIN_LEVEL ANDROID_LOG_VERBOSE
+#endif
+#endif
+
+static inline int ai_should_log(int prio) {
+    return __android_log_is_loggable(prio, LOG_TAG, LOG_MIN_LEVEL);
+}
+
+#if LOG_MIN_LEVEL <= ANDROID_LOG_VERBOSE
+#define LOGv(...) do { if (ai_should_log(ANDROID_LOG_VERBOSE)) __android_log_print(ANDROID_LOG_VERBOSE, LOG_TAG, __VA_ARGS__); } while (0)
+#else
+#define LOGv(...) ((void)0)
+#endif
+
+#if LOG_MIN_LEVEL <= ANDROID_LOG_DEBUG
+#define LOGd(...) do { if (ai_should_log(ANDROID_LOG_DEBUG)) __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, __VA_ARGS__); } while (0)
+#else
+#define LOGd(...) ((void)0)
+#endif
+
+#define LOGi(...)   do { if (ai_should_log(ANDROID_LOG_INFO )) __android_log_print(ANDROID_LOG_INFO , LOG_TAG, __VA_ARGS__); } while (0)
+#define LOGw(...)   do { if (ai_should_log(ANDROID_LOG_WARN )) __android_log_print(ANDROID_LOG_WARN , LOG_TAG, __VA_ARGS__); } while (0)
+#define LOGe(...)   do { if (ai_should_log(ANDROID_LOG_ERROR)) __android_log_print(ANDROID_LOG_ERROR, LOG_TAG, __VA_ARGS__); } while (0)
+
+static inline int android_log_prio_from_ggml(enum ggml_log_level level) {
+    switch (level) {
+        case GGML_LOG_LEVEL_ERROR: return ANDROID_LOG_ERROR;
+        case GGML_LOG_LEVEL_WARN:  return ANDROID_LOG_WARN;
+        case GGML_LOG_LEVEL_INFO:  return ANDROID_LOG_INFO;
+        case GGML_LOG_LEVEL_DEBUG: return ANDROID_LOG_DEBUG;
+        default:                   return ANDROID_LOG_DEFAULT;
+    }
+}
+
+static inline void aichat_android_log_callback(enum ggml_log_level level,
+                                              const char* text,
+                                              void* /*user*/) {
+    const int prio = android_log_prio_from_ggml(level);
+    if (!ai_should_log(prio)) return;
+    __android_log_write(prio, LOG_TAG, text);
+}