Bug 826176 - Part 1 - File extension support for accept attribute. r=smaug

dom/html/HTMLInputElement.cpp

@@ -7287,7 +7287,8 @@ HTMLInputElement::SetFilePickerFiltersFromAccept(nsIFilePicker* filePicker)
   nsTArray<nsFilePickerFilter> filters;
   nsString allExtensionsList;
 
-  bool allFiltersAreValid = true;
+  bool allMimeTypeFiltersAreValid = true;
+  bool atLeastOneFileExtensionFilter = false;
 
   // Retrieve all filters
   while (tokenizer.hasMoreTokens()) {
@@ -7314,6 +7315,10 @@ HTMLInputElement::SetFilePickerFiltersFromAccept(nsIFilePicker* filePicker)
       filterMask = nsIFilePicker::filterVideo;
       filterBundle->GetStringFromName(MOZ_UTF16("videoFilter"),
                                       getter_Copies(extensionListStr));
+    } else if (token.First() == '.') {
+      extensionListStr = NS_LITERAL_STRING("*") + token;
+      filterName = extensionListStr + NS_LITERAL_STRING("; ");
+      atLeastOneFileExtensionFilter = true;
     } else {
       //... if no image/audio/video filter is found, check mime types filters
       nsCOMPtr<nsIMIMEInfo> mimeInfo;
@@ -7322,7 +7327,7 @@ HTMLInputElement::SetFilePickerFiltersFromAccept(nsIFilePicker* filePicker)
                       EmptyCString(), // No extension
                       getter_AddRefs(mimeInfo))) ||
           !mimeInfo) {
-        allFiltersAreValid =  false;
+        allMimeTypeFiltersAreValid =  false;
         continue;
       }
 
@@ -7355,7 +7360,7 @@ HTMLInputElement::SetFilePickerFiltersFromAccept(nsIFilePicker* filePicker)
 
     if (!filterMask && (extensionListStr.IsEmpty() || filterName.IsEmpty())) {
       // No valid filter found
-      allFiltersAreValid = false;
+      allMimeTypeFiltersAreValid = false;
       continue;
     }
 
@@ -7395,9 +7400,8 @@ HTMLInputElement::SetFilePickerFiltersFromAccept(nsIFilePicker* filePicker)
     }
   }
 
-  // If all filters are known/valid, select the first filter as default;
-  // otherwise filterAll will remain the default filter
-  if (filters.Length() >= 1 && allFiltersAreValid) {
+  if (filters.Length() >= 1 &&
+      (allMimeTypeFiltersAreValid || atLeastOneFileExtensionFilter)) {
     // |filterAll| will always use index=0 so we need to set index=1 as the
     // current filter.
     filePicker->SetFilterIndex(1);

dom/html/HTMLInputElement.h

@@ -320,12 +320,18 @@ public:
    *
    * @note You should not call this function if the element has no @accept.
    * @note "All Files" filter is always set, no matter if there is a valid
-   * filter specifed or not.
-   * @note If there is only one valid filter that is audio or video or image,
-   * it will be selected as the default filter. Otherwise "All files" remains
-   * the default filter.
+   * filter specified or not.
    * @note If more than one valid filter is found, the "All Supported Types"
    * filter is added, which is the concatenation of all valid filters.
+   * @note "All Files" filter will be selected by default if unknown mime types
+   * have been specified and no file extension filter has been specified.
+   * Otherwise, specified filter or "All Supported Types" filter will be
+   * selected by default.
+   * The logic behind is that having unknown mime type means we might restrict
+   * user's input too much, as some filters will be missing.
+   * However, if author has also specified some file extension filters, it's
+   * likely those are fallback for the unusual mime type we haven't been able
+   * to resolve; so it's better to select author specified filters in that case.
    */
   void SetFilePickerFiltersFromAccept(nsIFilePicker* filePicker);
 

dom/html/test/forms/test_input_file_picker.html

@@ -27,6 +27,8 @@
   <input id='l' type="file" accept="image/*,image/gif,image/png">
   <input id='m' type="file" accept="image/gif,image/gif">
   <input id='n' type="file" accept="">
+  <input id='o' type="file" accept=".test">
+  <input id='p' type="file" accept="image/gif,.csv">
   <input id='z' type='file' accept="i/am,a,pathological,;,,,,test/case">
   <input id='hidden' hidden type='file'>
   <input id='untrusted-click' type='file'>
@@ -82,6 +84,8 @@ var testData = [["a", 1, MockFilePicker.filterImages, 1],
                 ["l", 4, imageExtensionList + "; " + "*.gif; *.png", 1],
                 ["m", 1, "*.gif", 1],
                 ["n", 0, undefined, 0],
+                ["o", 1, "*.test", 1],
+                ["p", 3, "*.gif; *.csv", 1],
                 ["z", 0, undefined, 0],
                 ["hidden", 0, undefined, 0],
                 ["untrusted-click", 0, undefined, 0],