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authorGravatar Abseil Team <absl-team@google.com>2023-06-14 13:41:04 -0700
committerGravatar Copybara-Service <copybara-worker@google.com>2023-06-14 13:42:23 -0700
commit4a82a1f4699348673426e255bbf8f8d8fadc7682 (patch)
tree3114204c28c81c1511507c7f781d6d18d2896b22 /absl/base
parentdc37a887fdc3d91ec9a67b93af9fa4c1ccb02545 (diff)
For web assembly, implement raw logging as direct JS console logging.
This bypasses the need for filesystem APIs just for stderr access. PiperOrigin-RevId: 540367155 Change-Id: Ib91dadac28cb5c8e571407b5dfa60c3e65539c95
Diffstat (limited to 'absl/base')
-rw-r--r--absl/base/internal/raw_logging.cc26
1 files changed, 25 insertions, 1 deletions
diff --git a/absl/base/internal/raw_logging.cc b/absl/base/internal/raw_logging.cc
index 6273e847..5ea49bca 100644
--- a/absl/base/internal/raw_logging.cc
+++ b/absl/base/internal/raw_logging.cc
@@ -21,6 +21,10 @@
#include <cstring>
#include <string>
+#ifdef __EMSCRIPTEN__
+#include <emscripten/console.h>
+#endif
+
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/internal/atomic_hook.h"
@@ -203,7 +207,27 @@ void DefaultInternalLog(absl::LogSeverity severity, const char* file, int line,
void AsyncSignalSafeWriteToStderr(const char* s, size_t len) {
absl::base_internal::ErrnoSaver errno_saver;
-#if defined(ABSL_HAVE_SYSCALL_WRITE)
+#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.
+ char buf[kLogBufSize];
+ if (len >= kLogBufSize) {
+ len = kLogBufSize - 1;
+ size_t trunc_len = sizeof(kTruncated) - 2;
+ strncpy(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) {
+ buf[len] = '\0';
+ // Skip a trailing newline character as emscripten_err adds one itself.
+ _emscripten_err(buf);
+ }
+#elif defined(ABSL_HAVE_SYSCALL_WRITE)
// We prefer calling write via `syscall` to minimize the risk of libc doing
// something "helpful".
syscall(SYS_write, STDERR_FILENO, s, len);