FileChooser: actually do store URL security bookmark in a smart pointer (as it was originally on an internal branch). Also update the docs to clearly indicate that a user has to use URL returned from FileChooser.

modules/juce_core/network/juce_URL.cpp

@@ -198,7 +198,7 @@ URL::URL (URL&& other)
       parameterValues (static_cast<StringArray&&> (other.parameterValues)),
       filesToUpload   (static_cast<ReferenceCountedArray<Upload>&&> (other.filesToUpload))
    #if JUCE_IOS
-    , bookmark        (other.bookmark)
+    , bookmark        (static_cast<Bookmark::Ptr&&> (other.bookmark))
    #endif
 {
 }
@@ -210,8 +210,8 @@ URL& URL::operator= (URL&& other)
     parameterNames  = static_cast<StringArray&&> (other.parameterNames);
     parameterValues = static_cast<StringArray&&> (other.parameterValues);
     filesToUpload   = static_cast<ReferenceCountedArray<Upload>&&> (other.filesToUpload);
-  #if JUCE_IOS
-    bookmark        = other.bookmark;
+   #if JUCE_IOS
+    bookmark        = static_cast<Bookmark::Ptr&&> (other.bookmark);
    #endif
 
     return *this;
@@ -501,14 +501,27 @@ bool URL::isProbablyAnEmailAddress (const String& possibleEmailAddress)
 }
 
 #if JUCE_IOS
+URL::Bookmark::Bookmark (void* bookmarkToUse)
+    : data (bookmarkToUse)
+{
+}
+
+URL::Bookmark::~Bookmark()
+{
+    [(NSData*) data release];
+}
+
 void setURLBookmark (URL& u, void* bookmark)
 {
-    u.bookmark = bookmark;
+    u.bookmark = new URL::Bookmark (bookmark);
 }
 
 void* getURLBookmark (URL& u)
 {
-    return u.bookmark;
+    if (u.bookmark.get() == nullptr)
+        return nullptr;
+
+    return u.bookmark.get()->data;
 }
 
 template <typename Stream> struct iOSFileStreamWrapperFlush    { static void flush (Stream*) {} };

modules/juce_core/network/juce_URL.h

@@ -529,7 +529,17 @@ private:
     ReferenceCountedArray<Upload> filesToUpload;
 
   #if JUCE_IOS
-    void* bookmark;
+    struct Bookmark : public ReferenceCountedObject
+    {
+        using Ptr = ReferenceCountedObjectPtr<Bookmark>;
+
+        Bookmark (void*);
+        ~Bookmark();
+
+        void* data;
+    };
+
+    Bookmark::Ptr bookmark;
 
     friend void setURLBookmark (URL&, void*);
     friend void* getURLBookmark (URL&);

modules/juce_gui_basics/filebrowser/juce_FileChooser.h

@@ -237,9 +237,14 @@ public:
         may return a URL to a remote document. If a local file is chosen then you can
         convert this file to a JUCE File class via the URL::getLocalFile method.
 
-        Note: on iOS it is best to dispose any copies of returned URL as soon as
-        you finish dealing with the file. This is because URL might be security
-        scoped and a system allows only for a limited number of such URLs.
+        Note: on iOS you must use the returned URL object directly (you are also
+        allowed to copy- or move-construct another URL from the returned URL), rather
+        than just storing the path as a String and then creating a new URL from that
+        String. This is because the returned URL contains internally a security
+        bookmark that is required to access the files pointed by it. Then, once you stop
+        dealing with the file pointed by the URL, you should dispose that URL object,
+        so that the security bookmark can be released by the system (only a limited
+        number of such URLs is allowed).
 
         @see getResult, URL::getLocalFile
     */
@@ -255,9 +260,14 @@ public:
         This array may be empty if no files were chosen, or can contain multiple entries
         if multiple files were chosen.
 
-        Note: on iOS it is best to dispose any copies of returned URLs as soon as
-        you finish dealing with the file. This is because URLs might be security
-        scoped and a system allows only for a limited number of such URLs.
+        Note: on iOS you must use the returned URL object directly (you are also
+        allowed to copy- or move-construct another URL from the returned URL), rather
+        than just storing the path as a String and then creating a new URL from that
+        String. This is because the returned URL contains internally a security
+        bookmark that is required to access the files pointed by it. Then, once you stop
+        dealing with the file pointed by the URL, you should dispose that URL object,
+        so that the security bookmark can be released by the system (only a limited
+        number of such URLs is allowed).
 
         @see getResults, URL::getLocalFile
     */

modules/juce_gui_basics/native/juce_ios_FileChooser.mm

@@ -217,6 +217,8 @@ private:
                                                   relativeToURL: nil
                                                           error: &error];
 
+                [bookmark retain];
+
                 [url stopAccessingSecurityScopedResource];
 
                 URL juceUrl (nsStringToJuce ([url absoluteString]));