Bug 1582892. Expose the number of strings in a Web IDL enum in a nice way. r=edgar

bzbarsky · bzbarsky · commit e09da7b0c7b9 · 2019-10-18T03:26:43.000Z
Differential Revision: https://phabricator.services.mozilla.com/D49536 --HG-- extra : moz-landing-system : lando
diff --git a/dom/base/ChromeUtils.cpp b/dom/base/ChromeUtils.cpp
@@ -672,12 +672,11 @@ void ChromeUtils::ClearRecentJSDevError(GlobalObject&) {
     return WebIDLProcType::_webidl
 
 static WebIDLProcType ProcTypeToWebIDL(mozilla::ProcType aType) {
-  // |strings| contains an extra non-enum value, so subtract one.
   // Max is the value of the last enum, not the length, so add one.
-  static_assert(ArrayLength(WebIDLProcTypeValues::strings) - 1 ==
-                    static_cast<size_t>(ProcType::Max) + 1,
-                "In order for this static cast to be okay, "
-                "WebIDLProcType must match ProcType exactly");
+  static_assert(
+      WebIDLProcTypeValues::Count == static_cast<size_t>(ProcType::Max) + 1,
+      "In order for this static cast to be okay, "
+      "WebIDLProcType must match ProcType exactly");
 
   switch (aType) {
     PROCTYPE_TO_WEBIDL_CASE(Web, Web);
diff --git a/dom/bindings/Codegen.py b/dom/bindings/Codegen.py
@@ -10098,17 +10098,25 @@ def __init__(self, enum):
             """
             extern const EnumEntry ${entry_array}[${entry_count}];
 
-            static_assert(static_cast<size_t>(${name}::EndGuard_) == ${entry_count} - 1,
-                          "Mismatch between enum strings and enum values");
+            static constexpr size_t Count = ${real_entry_count};
+
+            // Our "${entry_array}" contains an extra entry with a null string.
+            static_assert(mozilla::ArrayLength(${entry_array}) - 1 == Count,
+                          "Mismatch between enum strings and enum count");
+
+            static_assert(static_cast<size_t>(${name}::EndGuard_) == Count,
+                          "Mismatch between enum value and enum count");
 
             inline Span<const char> GetString(${name} stringId) {
-              MOZ_ASSERT(static_cast<${type}>(stringId) < static_cast<${type}>(${name}::EndGuard_));
+              MOZ_ASSERT(static_cast<${type}>(stringId) < Count);
               const EnumEntry& entry = ${entry_array}[static_cast<${type}>(stringId)];
               return MakeSpan(entry.value, entry.length);
             }
             """,
             entry_array=ENUM_ENTRY_VARIABLE_NAME,
             entry_count=self.nEnumStrings(),
+            # -1 because nEnumStrings() includes a string for EndGuard_
+            real_entry_count=self.nEnumStrings() - 1,
             name=self.enum.identifier.name,
             type=self.underlyingType())
         strings = CGNamespace(
@@ -14931,6 +14939,7 @@ def descriptorClearsPropsInSlots(descriptor):
         cgthings.extend(CGEnum(e) for e in enums)
 
         bindingDeclareHeaders["mozilla/Span.h"] = enums
+        bindingDeclareHeaders["mozilla/ArrayUtils.h"] = enums
 
         hasCode = (descriptors or callbackDescriptors or dictionaries or
                    callbacks)
diff --git a/dom/cache/CacheStorage.cpp b/dom/cache/CacheStorage.cpp
@@ -470,9 +470,8 @@ already_AddRefed<CacheStorage> CacheStorage::Constructor(
   static_assert(
       CHROME_ONLY_NAMESPACE == (uint32_t)CacheStorageNamespace::Chrome,
       "Chrome namespace should match webidl Chrome enum");
-  static_assert(
-      NUMBER_OF_NAMESPACES == (uint32_t)CacheStorageNamespace::EndGuard_,
-      "Number of namespace should match webidl endguard enum");
+  static_assert(NUMBER_OF_NAMESPACES == CacheStorageNamespaceValues::Count,
+                "Number of namespace should match webidl count");
 
   Namespace ns = static_cast<Namespace>(aNamespace);
   nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(aGlobal.GetAsSupports());
diff --git a/dom/cache/DBSchema.cpp b/dom/cache/DBSchema.cpp
@@ -229,7 +229,7 @@ static_assert(int(HeadersGuardEnum::None) == 0 &&
                   int(HeadersGuardEnum::Request_no_cors) == 2 &&
                   int(HeadersGuardEnum::Response) == 3 &&
                   int(HeadersGuardEnum::Immutable) == 4 &&
-                  int(HeadersGuardEnum::EndGuard_) == 5,
+                  HeadersGuardEnumValues::Count == 5,
               "HeadersGuardEnum values are as expected");
 static_assert(int(ReferrerPolicy::_empty) == 0 &&
                   int(ReferrerPolicy::No_referrer) == 1 &&
@@ -240,38 +240,38 @@ static_assert(int(ReferrerPolicy::_empty) == 0 &&
                   int(ReferrerPolicy::Same_origin) == 6 &&
                   int(ReferrerPolicy::Strict_origin) == 7 &&
                   int(ReferrerPolicy::Strict_origin_when_cross_origin) == 8 &&
-                  int(ReferrerPolicy::EndGuard_) == 9,
+                  ReferrerPolicyValues::Count == 9,
               "ReferrerPolicy values are as expected");
 static_assert(int(RequestMode::Same_origin) == 0 &&
                   int(RequestMode::No_cors) == 1 &&
                   int(RequestMode::Cors) == 2 &&
                   int(RequestMode::Navigate) == 3 &&
-                  int(RequestMode::EndGuard_) == 4,
+                  RequestModeValues::Count == 4,
               "RequestMode values are as expected");
 static_assert(int(RequestCredentials::Omit) == 0 &&
                   int(RequestCredentials::Same_origin) == 1 &&
                   int(RequestCredentials::Include) == 2 &&
-                  int(RequestCredentials::EndGuard_) == 3,
+                  RequestCredentialsValues::Count == 3,
               "RequestCredentials values are as expected");
 static_assert(int(RequestCache::Default) == 0 &&
                   int(RequestCache::No_store) == 1 &&
                   int(RequestCache::Reload) == 2 &&
                   int(RequestCache::No_cache) == 3 &&
                   int(RequestCache::Force_cache) == 4 &&
                   int(RequestCache::Only_if_cached) == 5 &&
-                  int(RequestCache::EndGuard_) == 6,
+                  RequestCacheValues::Count == 6,
               "RequestCache values are as expected");
 static_assert(int(RequestRedirect::Follow) == 0 &&
                   int(RequestRedirect::Error) == 1 &&
                   int(RequestRedirect::Manual) == 2 &&
-                  int(RequestRedirect::EndGuard_) == 3,
+                  RequestRedirectValues::Count == 3,
               "RequestRedirect values are as expected");
 static_assert(int(ResponseType::Basic) == 0 && int(ResponseType::Cors) == 1 &&
                   int(ResponseType::Default) == 2 &&
                   int(ResponseType::Error) == 3 &&
                   int(ResponseType::Opaque) == 4 &&
                   int(ResponseType::Opaqueredirect) == 5 &&
-                  int(ResponseType::EndGuard_) == 6,
+                  ResponseTypeValues::Count == 6,
               "ResponseType values are as expected");
 
 // If the static_asserts below fails, it means that you have changed the
diff --git a/dom/console/ConsoleInstance.cpp b/dom/console/ConsoleInstance.cpp
@@ -56,7 +56,7 @@ ConsoleLogLevel PrefToValue(const nsAString& aPref) {
     return ConsoleLogLevel::All;
   }
 
-  MOZ_ASSERT(index < (int)ConsoleLogLevel::EndGuard_);
+  MOZ_ASSERT(index < ConsoleLogLevelValues::Count);
   return static_cast<ConsoleLogLevel>(index);
 }
 
diff --git a/dom/media/mediasession/MediaSession.h b/dom/media/mediasession/MediaSession.h
@@ -51,7 +51,7 @@ class MediaSession final : public nsISupports, public nsWrapperCache {
   nsCOMPtr<nsPIDOMWindowInner> mParent;
 
   RefPtr<MediaMetadata> mMediaMetadata;
-  static const size_t ACTIONS = ArrayLength(MediaSessionActionValues::strings);
+  static const size_t ACTIONS = MediaSessionActionValues::Count;
   RefPtr<MediaSessionActionHandler> mActionHandlers[ACTIONS] = {nullptr};
 };
 
diff --git a/dom/permission/PermissionUtils.cpp b/dom/permission/PermissionUtils.cpp
@@ -19,9 +19,7 @@ static const nsLiteralCString kPermissionTypes[] = {
     // clang-format on
 };
 
-// `-1` for the last null entry.
-const size_t kPermissionNameCount =
-    MOZ_ARRAY_LENGTH(PermissionNameValues::strings) - 1;
+const size_t kPermissionNameCount = PermissionNameValues::Count;
 
 static_assert(MOZ_ARRAY_LENGTH(kPermissionTypes) == kPermissionNameCount,
               "kPermissionTypes and PermissionName count should match");
diff --git a/dom/serviceworkers/ServiceWorkerInfo.cpp b/dom/serviceworkers/ServiceWorkerInfo.cpp
@@ -43,7 +43,7 @@ static_assert(nsIServiceWorkerInfo::STATE_REDUNDANT ==
               "ServiceWorkerState enumeration value should match state values "
               "from nsIServiceWorkerInfo.");
 static_assert(nsIServiceWorkerInfo::STATE_UNKNOWN ==
-                  static_cast<uint16_t>(ServiceWorkerState::EndGuard_),
+                  ServiceWorkerStateValues::Count,
               "ServiceWorkerState enumeration value should match state values "
               "from nsIServiceWorkerInfo.");
 
diff --git a/dom/serviceworkers/ServiceWorkerManager.cpp b/dom/serviceworkers/ServiceWorkerManager.cpp
@@ -127,7 +127,7 @@ static_assert(
         static_cast<uint32_t>(RequestRedirect::Manual),
     "RequestRedirect enumeration value should make Necko Redirect mode value.");
 static_assert(
-    3 == static_cast<uint32_t>(RequestRedirect::EndGuard_),
+    3 == RequestRedirectValues::Count,
     "RequestRedirect enumeration value should make Necko Redirect mode value.");
 
 static_assert(
@@ -155,7 +155,7 @@ static_assert(
         static_cast<uint32_t>(RequestCache::Only_if_cached),
     "RequestCache enumeration value should match Necko Cache mode value.");
 static_assert(
-    6 == static_cast<uint32_t>(RequestCache::EndGuard_),
+    6 == RequestCacheValues::Count,
     "RequestCache enumeration value should match Necko Cache mode value.");
 
 static_assert(static_cast<uint16_t>(ServiceWorkerUpdateViaCache::Imports) ==
diff --git a/dom/webauthn/WebAuthnManager.cpp b/dom/webauthn/WebAuthnManager.cpp
@@ -539,8 +539,7 @@ already_AddRefed<Promise> WebAuthnManager::GetAssertion(
           NS_ConvertUTF16toUTF8 cStr(str);
           int i = FindEnumStringIndexImpl(
               cStr.get(), cStr.Length(), AuthenticatorTransportValues::strings);
-          if (i < 0 ||
-              i >= static_cast<int>(AuthenticatorTransport::EndGuard_)) {
+          if (i < 0) {
             continue;  // Unknown enum
           }
           AuthenticatorTransport t = static_cast<AuthenticatorTransport>(i);
diff --git a/toolkit/components/extensions/ExtensionPolicyService.cpp b/toolkit/components/extensions/ExtensionPolicyService.cpp
@@ -350,12 +350,13 @@ nsresult ExtensionPolicyService::InjectContentScripts(
           DocInfo docInfo(win);
 
           using RunAt = dom::ContentScriptRunAt;
+          namespace RunAtValues = dom::ContentScriptRunAtValues;
           using Scripts = AutoTArray<RefPtr<WebExtensionContentScript>, 8>;
 
-          constexpr uint8_t n = uint8_t(RunAt::EndGuard_);
-          Scripts scripts[n];
+          Scripts scripts[RunAtValues::Count];
 
           auto GetScripts = [&](RunAt aRunAt) -> Scripts&& {
+            static_assert(sizeof(aRunAt) == 1, "Our cast is wrong");
             return std::move(scripts[uint8_t(aRunAt)]);
           };
 

Original file line number	Diff line number	Diff line change
`@@ -56,7 +56,7 @@ ConsoleLogLevel PrefToValue(const nsAString& aPref) {`
`56`	`56`	`return ConsoleLogLevel::All;`
`57`	`57`	`}`
`58`	`58`
`59`		`- MOZ_ASSERT(index < (int)ConsoleLogLevel::EndGuard_);`
	`59`	`+ MOZ_ASSERT(index < ConsoleLogLevelValues::Count);`
`60`	`60`	`return static_cast<ConsoleLogLevel>(index);`
`61`	`61`	`}`
`62`	`62`