From f3ea24d72e6a1a1c77e08b79e886a3721f000823 Mon Sep 17 00:00:00 2001
From: Abseil Team <absl-team@google.com>
Date: Fri, 30 Jun 2023 09:32:16 -0700
Subject: Rolls back use of emscripten_errn as some implementations may not be
 compatible.

PiperOrigin-RevId: 544677169
Change-Id: I98874c5c8d1c9a057958b63e2b3c4fdd5daccd39
---
 absl/base/internal/raw_logging.cc | 26 +++++++++++---------------
 absl/log/internal/globals.cc      | 18 +++++++-----------
 2 files changed, 18 insertions(+), 26 deletions(-)

diff --git a/absl/base/internal/raw_logging.cc b/absl/base/internal/raw_logging.cc
index 1904026f..c866d957 100644
--- a/absl/base/internal/raw_logging.cc
+++ b/absl/base/internal/raw_logging.cc
@@ -206,31 +206,27 @@ 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.
-  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
+  // TODO(b/282811932): Avoid this copy if these emscripten functions can
+  // be updated to accept size directly.
   char buf[kLogBufSize];
   if (len >= kLogBufSize) {
     len = kLogBufSize - 1;
-    constexpr size_t trunc_len = sizeof(kTruncated) - 2;
-    memcpy(buf + len - trunc_len, kTruncated, trunc_len);
+    size_t trunc_len = sizeof(kTruncated) - 2;
+    strncpy(buf + len - trunc_len, kTruncated, trunc_len);
     buf[len] = '\0';
     len -= trunc_len;
-  } else {
+  } else if (len && s[len - 1] == '\n') {
+    len--;
+  }
+  strncpy(buf, s, len);
+  if (len) {
     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 cc7a9836..9ba997d5 100644
--- a/absl/log/internal/globals.cc
+++ b/absl/log/internal/globals.cc
@@ -16,7 +16,6 @@
 
 #include <atomic>
 #include <cstdio>
-
 #if defined(__EMSCRIPTEN__)
 #include <emscripten/console.h>
 #endif
@@ -26,7 +25,6 @@
 #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 {
@@ -60,18 +58,16 @@ 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.
-  // 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);
+  // 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();
+  }
   _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.
-- 
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