From d9a01008ab5bd8b5845b4f3074b3bdb453373736 Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Thu, 29 Jun 2023 14:20:23 -0700 Subject: Use new emscripten_errn to avoid copying strings. PiperOrigin-RevId: 544461113 Change-Id: Iafbd6daf2d03ae18a49ea449315ee7cd6a0e615e --- absl/base/internal/raw_logging.cc | 26 +++++++++++++++----------- absl/log/internal/globals.cc | 18 +++++++++++------- 2 files changed, 26 insertions(+), 18 deletions(-) (limited to 'absl') diff --git a/absl/base/internal/raw_logging.cc b/absl/base/internal/raw_logging.cc index c866d957..1904026f 100644 --- a/absl/base/internal/raw_logging.cc +++ b/absl/base/internal/raw_logging.cc @@ -206,27 +206,31 @@ void DefaultInternalLog(absl::LogSeverity severity, const char* file, int line, } // namespace void AsyncSignalSafeWriteError(const char* s, size_t len) { + if (!len) return; absl::base_internal::ErrnoSaver errno_saver; #if defined(__EMSCRIPTEN__) // In WebAssembly, bypass filesystem emulation via fwrite. - // TODO(b/282811932): Avoid this copy if these emscripten functions can - // be updated to accept size directly. + if (s[len - 1] == '\n') { + // Skip a trailing newline character as emscripten_errn adds one itself. + len--; + } + // emscripten_errn introduced in emscripten 3.1.41 +#if ABSL_INTERNAL_EMSCRIPTEN_VERSION >= 3001041 + emscripten_errn(s, len); +#else char buf[kLogBufSize]; if (len >= kLogBufSize) { len = kLogBufSize - 1; - size_t trunc_len = sizeof(kTruncated) - 2; - strncpy(buf + len - trunc_len, kTruncated, trunc_len); + constexpr size_t trunc_len = sizeof(kTruncated) - 2; + memcpy(buf + len - trunc_len, kTruncated, trunc_len); buf[len] = '\0'; len -= trunc_len; - } else if (len && s[len - 1] == '\n') { - len--; - } - strncpy(buf, s, len); - if (len) { + } else { buf[len] = '\0'; - // Skip a trailing newline character as emscripten_err adds one itself. - _emscripten_err(buf); } + memcpy(buf, s, len); + _emscripten_err(buf); +#endif #elif defined(ABSL_HAVE_SYSCALL_WRITE) // We prefer calling write via `syscall` to minimize the risk of libc doing // something "helpful". diff --git a/absl/log/internal/globals.cc b/absl/log/internal/globals.cc index 9ba997d5..cc7a9836 100644 --- a/absl/log/internal/globals.cc +++ b/absl/log/internal/globals.cc @@ -16,6 +16,7 @@ #include #include + #if defined(__EMSCRIPTEN__) #include #endif @@ -25,6 +26,7 @@ #include "absl/base/internal/raw_logging.h" #include "absl/base/log_severity.h" #include "absl/strings/string_view.h" +#include "absl/strings/strip.h" #include "absl/time/time.h" namespace absl { @@ -58,16 +60,18 @@ void SetInitialized() { } void WriteToStderr(absl::string_view message, absl::LogSeverity severity) { + if (message.empty()) return; #if defined(__EMSCRIPTEN__) // In WebAssembly, bypass filesystem emulation via fwrite. - // TODO(b/282811932): Avoid this copy if these emscripten functions can - // be updated to accept size directly. - std::string null_terminated_message(message); - if (!null_terminated_message.empty() && - null_terminated_message.back() == '\n') { - null_terminated_message.pop_back(); - } + // Skip a trailing newline character as emscripten_errn adds one itself. + const auto message_minus_newline = absl::StripSuffix(message, "\n"); + // emscripten_errn introduced in emscripten 3.1.41 +#if ABSL_INTERNAL_EMSCRIPTEN_VERSION >= 3001041 + emscripten_errn(message_minus_newline.data(), message_minus_newline.size()); +#else + std::string null_terminated_message(message_minus_newline); _emscripten_err(null_terminated_message.c_str()); +#endif #else // Avoid using std::cerr from this module since we may get called during // exit code, and cerr may be partially or fully destroyed by then. -- cgit v1.2.3