src: use custom fprintf alike to write errors to stderr

node.gyp

@@ -608,6 +608,7 @@
         'src/connect_wrap.h',
         'src/connection_wrap.h',
         'src/debug_utils.h',
+        'src/debug_utils-inl.h',
         'src/env.h',
         'src/env-inl.h',
         'src/handle_wrap.h',

src/debug_utils-inl.h

@@ -0,0 +1,91 @@
+#ifndef SRC_DEBUG_UTILS_INL_H_
+#define SRC_DEBUG_UTILS_INL_H_
+
+#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#include "debug_utils.h"
+
+#include <type_traits>
+
+namespace node {
+
+struct ToStringHelper {
+  template <typename T>
+  static std::string Convert(
+      const T& value,
+      std::string(T::* to_string)() const = &T::ToString) {
+    return (value.*to_string)();
+  }
+  template <typename T,
+            typename test_for_number = typename std::
+                enable_if<std::is_arithmetic<T>::value, bool>::type,
+            typename dummy = bool>
+  static std::string Convert(const T& value) { return std::to_string(value); }
+  static std::string Convert(const char* value) { return value; }
+  static std::string Convert(const std::string& value) { return value; }
+  static std::string Convert(bool value) { return value ? "true" : "false"; }
+};
+
+template <typename T>
+std::string ToString(const T& value) {
+  return ToStringHelper::Convert(value);
+}
+
+inline std::string SPrintFImpl(const char* format) {
+  return format;
+}
+
+template <typename Arg, typename... Args>
+std::string COLD_NOINLINE SPrintFImpl(  // NOLINT(runtime/string)
+    const char* format, Arg&& arg, Args&&... args) {
+  const char* p = strchr(format, '%');
+  if (p == nullptr) return format;
+  std::string ret(format, p);
+  // Ignore long / size_t modifiers
+  while (strchr("lz", *++p) != nullptr) {}
+  switch (*p) {
+    case '%': {
+      return ret + '%' + SPrintFImpl(p + 1,
+                                     std::forward<Arg>(arg),
+                                     std::forward<Args>(args)...);
+    }
+    default: {
+      return ret + '%' + SPrintFImpl(p,
+                                     std::forward<Arg>(arg),
+                                     std::forward<Args>(args)...);
+    }
+    case 'd':
+    case 'i':
+    case 'u':
+    case 's': ret += ToString(arg); break;
+    case 'p': {
+      CHECK(std::is_pointer<typename std::remove_reference<Arg>::type>::value);
+      char out[20];
+      int n = snprintf(out,
+                       sizeof(out),
+                       "%p",
+                       *reinterpret_cast<const void* const*>(&arg));
+      CHECK_GE(n, 0);
+      ret += out;
+      break;
+    }
+  }
+  return ret + SPrintFImpl(p + 1, std::forward<Args>(args)...);
+}
+
+template <typename... Args>
+std::string COLD_NOINLINE SPrintF(  // NOLINT(runtime/string)
+    const char* format, Args&&... args) {
+  return SPrintFImpl(format, std::forward<Args>(args)...);
+}
+
+template <typename... Args>
+void COLD_NOINLINE FPrintF(FILE* file, const char* format, Args&&... args) {
+  FWrite(file, SPrintF(format, std::forward<Args>(args)...));
+}
+
+}  // namespace node
+
+#endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#endif  // SRC_DEBUG_UTILS_INL_H_

src/debug_utils.cc

@@ -6,6 +6,10 @@
 #include <features.h>
 #endif
 
+#ifdef __ANDROID__
+#include <android/log.h>
+#endif
+
 #if defined(__linux__) && !defined(__GLIBC__) || \
     defined(__UCLIBC__) || \
     defined(_AIX)
@@ -437,6 +441,37 @@ std::vector<std::string> NativeSymbolDebuggingContext::GetLoadedLibraries() {
   return list;
 }
 
+void FWrite(FILE* file, const std::string& str) {
+  if (file != stderr && file != stdout) goto simple_fwrite;
+#ifdef _WIN32
+  HANDLE handle =
+      GetStdHandle(file == stdout ? STD_OUTPUT_HANDLE : STD_ERROR_HANDLE);
+
+  // Check if stderr is something other than a tty/console
+  if (handle == INVALID_HANDLE_VALUE || handle == nullptr ||
+      uv_guess_handle(_fileno(file)) != UV_TTY) {
+    goto simple_fwrite;
+  }
+
+  // Get required wide buffer size
+  int n = MultiByteToWideChar(CP_UTF8, 0, str.data(), str.size(), nullptr, 0);
+
+  std::vector<wchar_t> wbuf(n);
+  MultiByteToWideChar(CP_UTF8, 0, str.data(), str.size(), wbuf.data(), n);
+
+  // Don't include the final null character in the output
+  CHECK_GT(n, 0);
+  WriteConsoleW(handle, wbuf.data(), n - 1, nullptr, nullptr);
+  return;
+#elif defined(__ANDROID__)
+  if (file == stderr) {
+    __android_log_print(ANDROID_LOG_ERROR, "nodejs", "%s", str.data());
+    return;
+  }
+#endif
+simple_fwrite:
+  fwrite(str.data(), str.size(), 1, file);
+}
 
 }  // namespace node
 

src/debug_utils.h

@@ -22,22 +22,36 @@
 
 namespace node {
 
+template <typename T>
+inline std::string ToString(const T& value);
+
+// C++-style variant of sprintf()/fprintf() that:
+// - Returns an std::string
+// - Handles \0 bytes correctly
+// - Supports %p and %s. %d, %i and %u are aliases for %s.
+// - Accepts any class that has a ToString() method for stringification.
+template <typename... Args>
+inline std::string SPrintF(const char* format, Args&&... args);
+template <typename... Args>
+inline void FPrintF(FILE* file, const char* format, Args&&... args);
+void FWrite(FILE* file, const std::string& str);
+
 template <typename... Args>
 inline void FORCE_INLINE Debug(Environment* env,
                                DebugCategory cat,
                                const char* format,
                                Args&&... args) {
   if (!UNLIKELY(env->debug_enabled(cat)))
     return;
-  fprintf(stderr, format, std::forward<Args>(args)...);
+  FPrintF(stderr, format, std::forward<Args>(args)...);
 }
 
 inline void FORCE_INLINE Debug(Environment* env,
                                DebugCategory cat,
                                const char* message) {
   if (!UNLIKELY(env->debug_enabled(cat)))
     return;
-  fprintf(stderr, "%s", message);
+  FPrintF(stderr, "%s", message);
 }
 
 template <typename... Args>

src/inspector_profiler.cc

@@ -1,6 +1,6 @@
 #include "inspector_profiler.h"
 #include "base_object-inl.h"
-#include "debug_utils.h"
+#include "debug_utils-inl.h"
 #include "diagnosticfilename-inl.h"
 #include "memory_tracker-inl.h"
 #include "node_file.h"