Bug 1352348 - add a method to nsExternalHelperAppService that only fe…

…tches a string mimetype for an extension, r=bz,Paolo

MozReview-Commit-ID: 3p1pakC9g45

uriloader/exthandler/nsExternalHelperAppService.cpp

@@ -2729,14 +2729,12 @@ nsExternalHelperAppService::GetTypeFromExtension(const nsACString& aFileExt,
   }
 
   // Ask OS.
-  bool found = false;
-  nsCOMPtr<nsIMIMEInfo> mi = GetMIMEInfoFromOS(EmptyCString(), aFileExt, &found);
-  if (mi && found) {
-    return mi->GetMIMEType(aContentType);
+  if (GetMIMETypeFromOSForExtension(aFileExt, aContentType)) {
+    return NS_OK;
   }
 
   // Check extras array.
-  found = GetTypeFromExtras(aFileExt, aContentType);
+  bool found = GetTypeFromExtras(aFileExt, aContentType);
   if (found) {
     return NS_OK;
   }
@@ -2935,3 +2933,11 @@ bool nsExternalHelperAppService::GetTypeFromExtras(const nsACString& aExtension,
 
   return false;
 }
+
+bool
+nsExternalHelperAppService::GetMIMETypeFromOSForExtension(const nsACString& aExtension, nsACString& aMIMEType)
+{
+  bool found = false;
+  nsCOMPtr<nsIMIMEInfo> mimeInfo = GetMIMEInfoFromOS(EmptyCString(), aExtension, &found);
+  return found && mimeInfo && NS_SUCCEEDED(mimeInfo->GetMIMEType(aMIMEType));
+}

uriloader/exthandler/nsExternalHelperAppService.h

@@ -108,6 +108,15 @@ class nsExternalHelperAppService
   virtual nsresult OSProtocolHandlerExists(const char *aScheme,
                                                        bool *aExists) = 0;
 
+  /**
+   * Given an extension, get a MIME type string. If not overridden by
+   * the OS-specific nsOSHelperAppService, will call into GetMIMEInfoFromOS
+   * with an empty mimetype.
+   * @return true if we successfully found a mimetype.
+   */
+  virtual bool GetMIMETypeFromOSForExtension(const nsACString& aExtension,
+                                             nsACString& aMIMEType);
+
 protected:
   virtual ~nsExternalHelperAppService();
 

uriloader/exthandler/win/nsOSHelperAppService.cpp

@@ -392,46 +392,28 @@ nsOSHelperAppService::GetDefaultAppInfo(const nsAString& aAppInfo,
 
 already_AddRefed<nsMIMEInfoWin> nsOSHelperAppService::GetByExtension(const nsAFlatString& aFileExt, const char *aTypeHint)
 {
-  if (aFileExt.IsEmpty())
+  if (aExtension.IsEmpty())
     return nullptr;
 
-  // windows registry assumes your file extension is going to include the '.'.
-  // so make sure it's there...
-  nsAutoString fileExtToUse;
-  if (aFileExt.First() != char16_t('.'))
-    fileExtToUse = char16_t('.');
-
-  fileExtToUse.Append(aFileExt);
-
-  // Try to get an entry from the windows registry.
-  nsCOMPtr<nsIWindowsRegKey> regKey = 
-    do_CreateInstance("@mozilla.org/windows-registry-key;1");
-  if (!regKey) 
-    return nullptr; 
-
-  nsresult rv = regKey->Open(nsIWindowsRegKey::ROOT_KEY_CLASSES_ROOT,
-                             fileExtToUse,
-                             nsIWindowsRegKey::ACCESS_QUERY_VALUE);
-  if (NS_FAILED(rv))
-    return nullptr; 
-
+  // Determine the mime type.
   nsAutoCString typeToUse;
   if (aTypeHint && *aTypeHint) {
     typeToUse.Assign(aTypeHint);
-  }
-  else {
-    nsAutoString temp;
-    if (NS_FAILED(regKey->ReadStringValue(NS_LITERAL_STRING("Content Type"),
-                  temp)) || temp.IsEmpty()) {
-      return nullptr; 
-    }
-    // Content-Type is always in ASCII
-    LossyAppendUTF16toASCII(temp, typeToUse);
+  } else if (!GetMIMETypeFromOSForExtension(NS_ConvertUTF16toUTF8(aFileExt), typeToUse)) {
+    return nullptr;
   }
 
   RefPtr<nsMIMEInfoWin> mimeInfo = new nsMIMEInfoWin(typeToUse);
 
-  // don't append the '.'
+  // windows registry assumes your file extension is going to include the '.',
+  // but our APIs expect it to not be there, so make sure we normalize that bit.
+  nsAutoString fileExtToUse;
+  if (aFileExt.First() != char16_t('.'))
+    fileExtToUse = char16_t('.');
+
+  fileExtToUse.Append(aFileExt);
+
+  // don't append the '.' for our APIs.
   mimeInfo->AppendExtension(NS_ConvertUTF16toUTF8(Substring(fileExtToUse, 1)));
   mimeInfo->SetPreferredAction(nsIMIMEInfo::useSystemDefault);
 
@@ -458,8 +440,17 @@ already_AddRefed<nsMIMEInfoWin> nsOSHelperAppService::GetByExtension(const nsAFl
   } 
   else
   {
-    found = NS_SUCCEEDED(regKey->ReadStringValue(EmptyString(), 
-                                                 appInfo));
+    nsCOMPtr<nsIWindowsRegKey> regKey =
+      do_CreateInstance("@mozilla.org/windows-registry-key;1");
+    if (!regKey)
+      return nullptr;
+    nsresult rv = regKey->Open(nsIWindowsRegKey::ROOT_KEY_CLASSES_ROOT,
+                               fileExtToUse,
+                               nsIWindowsRegKey::ACCESS_QUERY_VALUE);
+    if (NS_SUCCEEDED(rv)) {
+      found = NS_SUCCEEDED(regKey->ReadStringValue(EmptyString(),
+                                                   appInfo));
+    }
   }
 
   // Bug 358297 - ignore the default handler, force the user to choose app
@@ -597,3 +588,40 @@ nsOSHelperAppService::GetProtocolHandlerInfoFromOS(const nsACString &aScheme,
   return NS_OK;
 }
 
+bool
+nsOSHelperAppService::GetMIMETypeFromOSForExtension(const nsACString& aExtension,
+                                                    nsACString& aMIMEType)
+{
+  if (aExtension.IsEmpty())
+    return false;
+
+  // windows registry assumes your file extension is going to include the '.'.
+  // so make sure it's there...
+  nsAutoString fileExtToUse;
+  if (aExtension.First() != '.')
+    fileExtToUse = char16_t('.');
+
+  AppendUTF8toUTF16(aExtension, fileExtToUse);
+
+  // Try to get an entry from the windows registry.
+  nsCOMPtr<nsIWindowsRegKey> regKey =
+    do_CreateInstance("@mozilla.org/windows-registry-key;1");
+  if (!regKey)
+    return false;
+
+  nsresult rv = regKey->Open(nsIWindowsRegKey::ROOT_KEY_CLASSES_ROOT,
+                             fileExtToUse,
+                             nsIWindowsRegKey::ACCESS_QUERY_VALUE);
+  if (NS_FAILED(rv))
+    return false;
+
+  nsAutoString mimeType;
+  if (NS_FAILED(regKey->ReadStringValue(NS_LITERAL_STRING("Content Type"),
+                mimeType)) || mimeType.IsEmpty()) {
+    return false;
+  }
+  // Content-Type is always in ASCII
+  aMIMEType.Truncate();
+  LossyAppendUTF16toASCII(mimeType, aMIMEType);
+  return true;
+}

uriloader/exthandler/win/nsOSHelperAppService.h

@@ -40,6 +40,8 @@ class nsOSHelperAppService : public nsExternalHelperAppService
   NS_IMETHOD GetProtocolHandlerInfoFromOS(const nsACString &aScheme, 
                                           bool *found,
                                           nsIHandlerInfo **_retval);
+  virtual bool GetMIMETypeFromOSForExtension(const nsACString& aExtension,
+                                             nsACString& aMIMEType) override;
 
   /** Get the string value of a registry value and store it in result.
    * @return true on success, false on failure