Bug 1174566 - More helpful MediaKeySystemAccess error messages. r=edwin

dom/media/eme/MediaKeySystemAccess.cpp

@@ -141,7 +141,8 @@ AdobePluginVoucherExists(const nsACString& aVersionStr)
 static MediaKeySystemStatus
 EnsureMinCDMVersion(mozIGeckoMediaPluginService* aGMPService,
                     const nsAString& aKeySystem,
-                    int32_t aMinCdmVersion)
+                    int32_t aMinCdmVersion,
+                    nsACString& aOutMessage)
 {
   nsTArray<nsCString> tags;
   tags.AppendElement(NS_ConvertUTF16toUTF8(aKeySystem));
@@ -151,10 +152,12 @@ EnsureMinCDMVersion(mozIGeckoMediaPluginService* aGMPService,
                                                     &tags,
                                                     &hasPlugin,
                                                     versionStr))) {
+    aOutMessage = NS_LITERAL_CSTRING("GetPluginVersionForAPI failed");
     return MediaKeySystemStatus::Error;
   }
 
   if (!hasPlugin) {
+    aOutMessage = NS_LITERAL_CSTRING("CDM is not installed");
     return MediaKeySystemStatus::Cdm_not_installed;
   }
 
@@ -165,6 +168,7 @@ EnsureMinCDMVersion(mozIGeckoMediaPluginService* aGMPService,
   nsresult rv;
   int32_t version = versionStr.ToInteger(&rv);
   if (NS_FAILED(rv) || version < 0 || aMinCdmVersion > version) {
+    aOutMessage = NS_LITERAL_CSTRING("Installed CDM version insufficient");
     return MediaKeySystemStatus::Cdm_insufficient_version;
   }
 
@@ -173,8 +177,16 @@ EnsureMinCDMVersion(mozIGeckoMediaPluginService* aGMPService,
       aKeySystem.EqualsLiteral("com.adobe.primetime")) {
     // Verify that anti-virus hasn't "helpfully" deleted the Adobe GMP DLL,
     // as we suspect may happen (Bug 1160382).
-    if (!AdobePluginDLLExists(versionStr) ||
-        !AdobePluginVoucherExists(versionStr)) {
+    bool somethingMissing = false;
+    if (!AdobePluginDLLExists(versionStr)) {
+      aOutMessage = NS_LITERAL_CSTRING("Adobe DLL was expected to be on disk but was not");
+      somethingMissing = true;
+    }
+    if (!AdobePluginVoucherExists(versionStr)) {
+      aOutMessage = NS_LITERAL_CSTRING("Adobe plugin voucher was expected to be on disk but was not");
+      somethingMissing = true;
+    }
+    if (somethingMissing) {    
       NS_WARNING("Adobe EME plugin or voucher disappeared from disk!");
       // Reset the prefs that Firefox's GMP downloader sets, so that
       // Firefox will try to download the plugin next time the updater runs.
@@ -191,20 +203,23 @@ EnsureMinCDMVersion(mozIGeckoMediaPluginService* aGMPService,
 /* static */
 MediaKeySystemStatus
 MediaKeySystemAccess::GetKeySystemStatus(const nsAString& aKeySystem,
-                                         int32_t aMinCdmVersion)
+                                         int32_t aMinCdmVersion,
+                                         nsACString& aOutMessage)
 {
   MOZ_ASSERT(Preferences::GetBool("media.eme.enabled", false));
   nsCOMPtr<mozIGeckoMediaPluginService> mps =
     do_GetService("@mozilla.org/gecko-media-plugin-service;1");
   if (NS_WARN_IF(!mps)) {
+    aOutMessage = NS_LITERAL_CSTRING("Failed to get GMP service");
     return MediaKeySystemStatus::Error;
   }
 
   if (aKeySystem.EqualsLiteral("org.w3.clearkey")) {
     if (!Preferences::GetBool("media.eme.clearkey.enabled", true)) {
+      aOutMessage = NS_LITERAL_CSTRING("ClearKey was disabled");
       return MediaKeySystemStatus::Cdm_disabled;
     }
-    return EnsureMinCDMVersion(mps, aKeySystem, aMinCdmVersion);
+    return EnsureMinCDMVersion(mps, aKeySystem, aMinCdmVersion, aOutMessage);
   }
 
 #ifdef XP_WIN
@@ -212,20 +227,21 @@ MediaKeySystemAccess::GetKeySystemStatus(const nsAString& aKeySystem,
        aKeySystem.EqualsLiteral("com.adobe.primetime"))) {
     // Win Vista and later only.
     if (!IsVistaOrLater()) {
+      aOutMessage = NS_LITERAL_CSTRING("Minimum Windows version not met for Adobe EME");
       return MediaKeySystemStatus::Cdm_not_supported;
     }
     if (!Preferences::GetBool("media.gmp-eme-adobe.enabled", false)) {
+      aOutMessage = NS_LITERAL_CSTRING("Adobe EME disabled");
       return MediaKeySystemStatus::Cdm_disabled;
     }
-    if (!MP4Decoder::CanCreateH264Decoder() ||
-        !MP4Decoder::CanCreateAACDecoder() ||
-        !EMEVoucherFileExists()) {
+    if (!EMEVoucherFileExists()) {
       // The system doesn't have the codecs that Adobe EME relies
       // on installed, or doesn't have a voucher for the plugin-container.
       // Adobe EME isn't going to work, so don't advertise that it will.
+      aOutMessage = NS_LITERAL_CSTRING("Plugin-container voucher not present");
       return MediaKeySystemStatus::Cdm_not_supported;
     }
-    return EnsureMinCDMVersion(mps, aKeySystem, aMinCdmVersion);
+    return EnsureMinCDMVersion(mps, aKeySystem, aMinCdmVersion, aOutMessage);
   }
 #endif
 

dom/media/eme/MediaKeySystemAccess.h

@@ -44,8 +44,11 @@ public:
 
   already_AddRefed<Promise> CreateMediaKeys(ErrorResult& aRv);
 
+
+
   static MediaKeySystemStatus GetKeySystemStatus(const nsAString& aKeySystem,
-                                                 int32_t aMinCdmVersion);
+                                                 int32_t aMinCdmVersion,
+                                                 nsACString& aOutExceptionMessage);
 
   static bool IsSupported(const nsAString& aKeySystem,
                           const Sequence<MediaKeySystemOptions>& aOptions);

dom/media/eme/MediaKeySystemAccessManager.cpp

@@ -105,7 +105,8 @@ MediaKeySystemAccessManager::Request(DetailedPromise* aPromise,
     return;
   }
 
-  MediaKeySystemStatus status = MediaKeySystemAccess::GetKeySystemStatus(keySystem, minCdmVersion);
+  nsAutoCString message;
+  MediaKeySystemStatus status = MediaKeySystemAccess::GetKeySystemStatus(keySystem, minCdmVersion, message);
   if ((status == MediaKeySystemStatus::Cdm_not_installed ||
        status == MediaKeySystemStatus::Cdm_insufficient_version) &&
       keySystem.EqualsLiteral("com.adobe.primetime")) {