Bug 1746052, add a means to get the filename that should be used for …

…saving an image to disk, r=aosmond

Differential Revision: https://phabricator.services.mozilla.com/D135950

image/imgIRequest.idl

@@ -100,6 +100,14 @@ interface imgIRequest : nsIRequest
 
   readonly attribute string mimeType;
 
+  /**
+   * The filename that should be used when saving the image. This is determined
+   * from the Content-Disposition, if present, or the uri of the image. This
+   * filename should be validated using nsIMIMEService::GetValidFilenameForSaving
+   * before creating the file.
+   */
+  readonly attribute ACString fileName;
+
   /**
    * Clone this request; the returned request will have aObserver as the
    * observer.  aObserver will be notified synchronously (before the clone()

image/imgRequest.cpp

@@ -31,13 +31,15 @@
 #include "nsIScriptSecurityManager.h"
 #include "nsComponentManagerUtils.h"
 #include "nsContentUtils.h"
+#include "nsEscape.h"
 
 #include "plstr.h"   // PL_strcasestr(...)
 #include "prtime.h"  // for PR_Now
 #include "nsNetUtil.h"
 #include "nsIProtocolHandler.h"
 #include "imgIRequest.h"
 #include "nsProperties.h"
+#include "nsIURL.h"
 
 #include "mozilla/IntegerPrintfMacros.h"
 #include "mozilla/SizeOfState.h"
@@ -461,6 +463,30 @@ already_AddRefed<image::Image> imgRequest::GetImage() const {
   return image.forget();
 }
 
+void imgRequest::GetFileName(nsACString& aFileName) {
+  nsAutoString fileName;
+
+  nsCOMPtr<nsISupportsCString> supportscstr;
+  if (NS_SUCCEEDED(mProperties->Get("content-disposition",
+                                    NS_GET_IID(nsISupportsCString),
+                                    getter_AddRefs(supportscstr))) &&
+      supportscstr) {
+    nsAutoCString cdHeader;
+    supportscstr->GetData(cdHeader);
+    NS_GetFilenameFromDisposition(fileName, cdHeader);
+  }
+
+  if (fileName.IsEmpty()) {
+    nsCOMPtr<nsIURL> imgUrl(do_QueryInterface(mURI));
+    if (imgUrl) {
+      imgUrl->GetFileName(aFileName);
+      NS_UnescapeURL(aFileName);
+    }
+  } else {
+    aFileName = NS_ConvertUTF16toUTF8(fileName);
+  }
+}
+
 int32_t imgRequest::Priority() const {
   int32_t priority = nsISupportsPriority::PRIORITY_NORMAL;
   nsCOMPtr<nsISupportsPriority> p = do_QueryInterface(mRequest);

image/imgRequest.h

@@ -151,6 +151,8 @@ class imgRequest final : public nsIStreamListener,
   /// Returns a non-owning pointer to this imgRequest's MIME type.
   const char* GetMimeType() const { return mContentType.get(); }
 
+  void GetFileName(nsACString& aFileName);
+
   /// @return the priority of the underlying network request, or
   /// PRIORITY_NORMAL if it doesn't support nsISupportsPriority.
   int32_t Priority() const;

image/imgRequestProxy.cpp

@@ -747,6 +747,16 @@ imgRequestProxy::GetMimeType(char** aMimeType) {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+imgRequestProxy::GetFileName(nsACString& aFileName) {
+  if (!GetOwner()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  GetOwner()->GetFileName(aFileName);
+  return NS_OK;
+}
+
 imgRequestProxy* imgRequestProxy::NewClonedProxy() {
   return new imgRequestProxy();
 }