1 // Copyright 2023 The Chromium Authors
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "third_party/jni_zero/logging.h"
6
7 #include <stdarg.h>
8 #include <stdio.h>
9 #include <atomic>
10 #include <memory>
11 #ifndef JNI_ZERO_IS_ROBOLECTRIC
12 #include <android/log.h>
13 #endif
14
15 namespace jni_zero {
16
17 std::atomic<LogMessageCallback> g_log_callback{};
18
SetLogMessageCallback(LogMessageCallback callback)19 void SetLogMessageCallback(LogMessageCallback callback) {
20 g_log_callback.store(callback, std::memory_order_relaxed);
21 }
22
LogMessage(LogLev level,const char * fname,int line,const char * fmt,...)23 void LogMessage(LogLev level,
24 const char* fname,
25 int line,
26 const char* fmt,
27 ...) {
28 char stack_buf[512];
29 std::unique_ptr<char[]> large_buf;
30 char* log_msg = &stack_buf[0];
31
32 // By default use a stack allocated buffer because most log messages are quite
33 // short. In rare cases they can be larger (e.g. --help). In those cases we
34 // pay the cost of allocating the buffer on the heap.
35 for (size_t max_len = sizeof(stack_buf);;) {
36 va_list args;
37 va_start(args, fmt);
38 int res = vsnprintf(log_msg, max_len, fmt, args);
39 va_end(args);
40
41 // If for any reason the print fails, overwrite the message but still print
42 // it. The code below will attach the filename and line, which is still
43 // useful.
44 if (res < 0) {
45 snprintf(log_msg, max_len, "%s", "[printf format error]");
46 break;
47 }
48 // if res == max_len, vsnprintf saturated the input buffer. Retry with a
49 // larger buffer in that case (within reasonable limits).
50 if (res < static_cast<int>(max_len) || max_len >= 128 * 1024) {
51 break;
52 }
53
54 max_len *= 4;
55 large_buf.reset(new char[max_len]);
56 log_msg = &large_buf[0];
57 }
58
59 LogMessageCallback cb = g_log_callback.load(std::memory_order_relaxed);
60 if (cb) {
61 cb({level, line, fname, log_msg});
62 return;
63 }
64
65 #ifdef JNI_ZERO_IS_ROBOLECTRIC
66 fprintf(stderr, "%s:%d %s\n", fname, line, log_msg);
67 #else
68 __android_log_print(int{ANDROID_LOG_DEBUG} + level, "jni_zero", "%s:%d %s",
69 fname, line, log_msg);
70 #endif
71 if (level >= kLogFatal) {
72 JNI_ZERO_IMMEDIATE_CRASH();
73 }
74 }
75
76 } // namespace jni_zero
77