Bug 1711181 - Add QM_OR_ELSE_LOG macro; r=dom-storage-reviewers,jstutte

Differential Revision: https://phabricator.services.mozilla.com/D114936

dom/quota/QuotaCommon.cpp

@@ -406,6 +406,14 @@ nsDependentCSubstring MakeSourceFileRelativePath(
 void LogError(const nsACString& aExpr, const Maybe<nsresult> aRv,
               const nsACString& aSourceFilePath, const int32_t aSourceFileLine,
               const Severity aSeverity) {
+  // TODO: Add MOZ_LOG support, bug 1711661.
+
+  // We have to ignore failures with the Log severity. until we have support
+  // for MOZ_LOG.
+  if (aSeverity == Severity::Log) {
+    return;
+  }
+
 #if defined(EARLY_BETA_OR_EARLIER) || defined(DEBUG)
   nsAutoCString extraInfosString;
 
@@ -435,6 +443,8 @@ void LogError(const nsACString& aExpr, const Maybe<nsresult> aRv,
         return "WARNING"_ns;
       case Severity::Note:
         return "NOTE"_ns;
+      case Severity::Log:
+        return "LOG"_ns;
     }
     MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE("Bad severity value!");
   }();

dom/quota/QuotaCommon.h

@@ -872,6 +872,22 @@ class NotNull;
     return orElseFunc(firstRes);                                               \
   })
 
+/**
+ * QM_OR_ELSE_LOG is like QM_OR_ELSE_WARN. The only difference is that
+ * failures are reported using the lowest severity which is currently ignored
+ * in LogError, so nothing goes to the console, browser console and telemetry.
+ * Since nothing goes to the telemetry, the macro can't signal the end of the
+ * underlying error stack or change the type of the error stack in the
+ * telemetry. For that reason, the expression shouldn't contain nested QM_TRY
+ * macro uses.
+ */
+#define QM_OR_ELSE_LOG(expr, orElseFunc)                                      \
+  (expr).orElse([&](const auto& firstRes) {                                   \
+    mozilla::dom::quota::QM_HANDLE_ERROR(#expr, firstRes,                     \
+                                         mozilla::dom::quota::Severity::Log); \
+    return orElseFunc(firstRes);                                              \
+  })
+
 // Telemetry probes to collect number of failure during the initialization.
 #ifdef NIGHTLY_BUILD
 #  define RECORD_IN_NIGHTLY(_recorder, _status) \
@@ -1202,6 +1218,7 @@ enum class Severity {
   Error,
   Warning,
   Note,
+  Log,
 };
 
 void LogError(const nsACString& aExpr, Maybe<nsresult> aRv,