Better logging system

Use C++ magic to strip out debug logs at compile time

native/jni/utils/include/logging.hpp

@@ -1,17 +1,15 @@
 #pragma once
 
-#include <errno.h>
-#include <stdarg.h>
-#include <string.h>
+#include <cerrno>
+#include <cstdarg>
+#include <cstring>
 
-__BEGIN_DECLS
-
-typedef enum {
+enum {
 	L_DEBUG,
 	L_INFO,
 	L_WARN,
 	L_ERR
-} log_type;
+};
 
 struct log_callback {
 	int (*d)(const char* fmt, va_list ap);
@@ -21,20 +19,19 @@ struct log_callback {
 	void (*ex)(int code);
 };
 
-extern struct log_callback log_cb;
+extern log_callback log_cb;
 
-#define LOGD(...) log_handler(L_DEBUG, __VA_ARGS__)
-#define LOGI(...) log_handler(L_INFO, __VA_ARGS__)
-#define LOGW(...) log_handler(L_WARN, __VA_ARGS__)
-#define LOGE(...) log_handler(L_ERR, __VA_ARGS__)
-#define PLOGE(fmt, args...) LOGE(fmt " failed with %d: %s\n", ##args, errno, strerror(errno))
+#define LOGD(...) log_handler<L_DEBUG>(__VA_ARGS__)
+#define LOGI(...) log_handler<L_INFO>(__VA_ARGS__)
+#define LOGW(...) log_handler<L_WARN>(__VA_ARGS__)
+#define LOGE(...) log_handler<L_ERR>(__VA_ARGS__)
+#define PLOGE(fmt, args...) LOGE(fmt " failed with %d: %s\n", ##args, errno, std::strerror(errno))
 
-int nop_log(const char *fmt, va_list ap);
-void nop_ex(int i);
+int nop_log(const char *, va_list);
+void nop_ex(int);
 
 void no_logging();
 void cmdline_logging();
 
-int log_handler(log_type t, const char *fmt, ...);
-
-__END_DECLS
+template<int type>
+void log_handler(const char *fmt, ...) __printflike(1, 2);

native/jni/utils/logging.cpp

@@ -1,15 +1,16 @@
-#include <stdio.h>
-#include <stdlib.h>
+#include <cstdio>
+#include <cstdlib>
 
 #include <logging.hpp>
+#include <flags.hpp>
 
-int nop_log(const char *fmt, va_list ap) {
-	return 0;
-}
+using namespace std;
 
-void nop_ex(int i) {}
+int nop_log(const char *, va_list) { return 0; }
 
-struct log_callback log_cb = {
+void nop_ex(int) {}
+
+log_callback log_cb = {
 	.d = nop_log,
 	.i = nop_log,
 	.w = nop_log,
@@ -25,37 +26,42 @@ void no_logging() {
 	log_cb.ex = nop_ex;
 }
 
-static int vprinte(const char *fmt, va_list ap) {
+static int vprintfe(const char *fmt, va_list ap) {
 	return vfprintf(stderr, fmt, ap);
 }
 
 void cmdline_logging() {
-	log_cb.d = vprinte;
+	log_cb.d = vprintfe;
 	log_cb.i = vprintf;
-	log_cb.w = vprinte;
-	log_cb.e = vprinte;
+	log_cb.w = vprintfe;
+	log_cb.e = vprintfe;
 	log_cb.ex = exit;
 }
 
-int log_handler(log_type t, const char *fmt, ...) {
+template <int type>
+void log_handler(const char *fmt, ...) {
 	va_list argv;
-	int ret = 0;
 	va_start(argv, fmt);
-	switch (t) {
-	case L_DEBUG:
-		ret = log_cb.d(fmt, argv);
-		break;
-	case L_INFO:
-		ret = log_cb.i(fmt, argv);
-		break;
-	case L_WARN:
-		ret = log_cb.w(fmt, argv);
-		break;
-	case L_ERR:
-		ret = log_cb.e(fmt, argv);
+	if constexpr (type == L_DEBUG) {
+		log_cb.d(fmt, argv);
+	} else if constexpr (type == L_INFO) {
+		log_cb.i(fmt, argv);
+	} else if constexpr (type == L_WARN) {
+		log_cb.w(fmt, argv);
+	} else if constexpr (type == L_ERR) {
+		log_cb.e(fmt, argv);
 		log_cb.ex(1);
-		break;
 	}
 	va_end(argv);
-	return ret;
 }
+
+template void log_handler<L_INFO>(const char *fmt, ...);
+template void log_handler<L_WARN>(const char *fmt, ...);
+template void log_handler<L_ERR>(const char *fmt, ...);
+
+#ifdef MAGISK_DEBUG
+template void log_handler<L_DEBUG>(const char *fmt, ...);
+#else
+// Strip debug logging for release builds
+template <> void log_handler<L_DEBUG>(const char *fmt, ...) {}
+#endif

native/jni/utils/xwrap.cpp

@@ -84,7 +84,7 @@ ssize_t xread(int fd, void *buf, size_t count) {
 ssize_t xxread(int fd, void *buf, size_t count) {
 	int ret = read(fd, buf, count);
 	if (count != ret) {
-		PLOGE("read (%d != %d)", count, ret);
+		PLOGE("read (%zu != %d)", count, ret);
 	}
 	return ret;
 }