Bug 1951723 - Add Formatted Logging to JS Logging. r=mgaudet

Differential Revision: https://phabricator.services.mozilla.com/D241743

js/public/experimental/LoggingInterface.h

@@ -13,6 +13,7 @@
 #include "mozilla/LoggingCore.h"
 
 #include "jstypes.h"
+#include "fmt/format.h"
 #include "js/GCAPI.h"
 
 struct JSContext;
@@ -55,6 +56,9 @@ struct LoggingInterface {
                      const char* aFmt, va_list ap)
       MOZ_FORMAT_PRINTF(3, 0) = nullptr;
 
+  void (*logPrintFMT)(const OpaqueLogger aModule, mozilla::LogLevel aLevel,
+                      fmt::string_view, fmt::format_args);
+
   // Return a reference to the provided OpaqueLogger's level ref; Implementation
   // wise this can be a small violation of encapsulation but is intended to help
   // ensure that we can build lightweight logging without egregious costs to
@@ -71,6 +75,13 @@ struct LoggingInterface {
     va_end(ap);
   }
 
+  template <typename... T>
+  void logPrintFmt(const OpaqueLogger aModule, mozilla::LogLevel aLevel,
+                   fmt::format_string<T...> aFmt, T&&... aArgs) {
+    JS::AutoSuppressGCAnalysis suppress;
+    this->logPrintFMT(aModule, aLevel, aFmt, fmt::make_format_args(aArgs...));
+  }
+
   // Used to ensure that before we use an interface, it's successfully been
   // completely filled in.
   bool isComplete() const {

js/src/shell/js.cpp

@@ -68,6 +68,7 @@
 #include "jsapi.h"
 #include "jsfriendapi.h"
 #include "jstypes.h"
+#include "fmt/format.h"
 #ifndef JS_WITHOUT_NSPR
 #  include "prerror.h"
 #  include "prlink.h"
@@ -384,8 +385,15 @@ void LogPrintVA(const JS::OpaqueLogger logger, mozilla::LogLevel level,
   fprintf(stderr, "\n");
 }
 
+void LogPrintFmt(const JS::OpaqueLogger logger, mozilla::LogLevel level,
+                 fmt::string_view fmt, fmt::format_args args) {
+  ShellLogModule* mod = static_cast<ShellLogModule*>(logger);
+  fmt::print(stderr, FMT_STRING("[{}] {}\n"), mod->name,
+             fmt::vformat(fmt, args));
+}
+
 JS::LoggingInterface shellLoggingInterface = {GetLoggerByName, LogPrintVA,
-                                              GetLevelRef};
+                                              LogPrintFmt, GetLevelRef};
 
 static void ToLower(const char* src, char* dest, size_t len) {
   for (size_t c = 0; c < len; c++) {

js/src/vm/Logging.h

@@ -113,8 +113,17 @@ FOR_EACH_JS_LOG_MODULE(DECLARE_MODULE);
                                         LogLevel::log_level, __VA_ARGS__); \
       }                                                                    \
     } while (0);
+#  define JS_LOG_FMT(name, log_level, fmt, ...)                             \
+    do {                                                                    \
+      if (name##Module.shouldLog(LogLevel::log_level)) {                    \
+        name##Module.interface.logPrintFmt(name##Module.logger,             \
+                                           LogLevel::log_level,             \
+                                           FMT_STRING(fmt), ##__VA_ARGS__); \
+      }                                                                     \
+    } while (0);
 #else
 #  define JS_LOG(module, log_level, ...)
+#  define JS_LOG_FMT(module, log_level, fmt, ...)
 #endif
 
 #undef JS_LOGGING

js/xpconnect/src/XPCJSContext.cpp

@@ -52,6 +52,7 @@
 #include "js/MemoryMetrics.h"
 #include "js/Prefs.h"
 #include "js/WasmFeatures.h"
+#include "fmt/format.h"
 #include "mozilla/dom/BindingUtils.h"
 #include "mozilla/dom/ContentChild.h"
 #include "mozilla/dom/Document.h"
@@ -1182,13 +1183,20 @@ static void LogPrintVA(JS::OpaqueLogger aLogger, mozilla::LogLevel level,
   logmod->Printv(level, aFmt, ap);
 }
 
+static void LogPrintFMT(JS::OpaqueLogger aLogger, mozilla::LogLevel level,
+                        fmt::string_view fmt, fmt::format_args args) {
+  LogModule* logmod = static_cast<LogModule*>(aLogger);
+
+  logmod->PrintvFmt(level, fmt, args);
+}
+
 static AtomicLogLevel& GetLevelRef(JS::OpaqueLogger aLogger) {
   LogModule* logmod = static_cast<LogModule*>(aLogger);
   return logmod->LevelRef();
 }
 
 static JS::LoggingInterface loggingInterface = {GetLoggerByName, LogPrintVA,
-                                                GetLevelRef};
+                                                LogPrintFMT, GetLevelRef};
 
 nsresult XPCJSContext::Initialize() {
   if (StaticPrefs::javascript_options_external_thread_pool_DoNotUseDirectly()) {