prevent overwriting external capture URIs

Closes #4719
fixes #4538
// FREEBIE

src/org/thoughtcrime/securesms/ConversationActivity.java

@@ -995,7 +995,7 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
     case AttachmentTypeSelectorAdapter.ADD_CONTACT_INFO:
       AttachmentManager.selectContactInfo(this, PICK_CONTACT_INFO); break;
     case AttachmentTypeSelectorAdapter.TAKE_PHOTO:
-      attachmentManager.capturePhoto(this, recipients, TAKE_PHOTO); break;
+      attachmentManager.capturePhoto(this, TAKE_PHOTO); break;
     }
   }
 

src/org/thoughtcrime/securesms/mms/AttachmentManager.java

@@ -126,8 +126,8 @@ public class AttachmentManager {
   }
 
   private void setSlide(@NonNull Slide slide) {
-    if (getSlideUri() != null)                              cleanup(getSlideUri());
-    if (captureUri != null && slide.getUri() != captureUri) cleanup(captureUri);
+    if (getSlideUri() != null)                                    cleanup(getSlideUri());
+    if (captureUri != null && !captureUri.equals(slide.getUri())) cleanup(captureUri);
 
     this.captureUri = null;
     this.slide      = Optional.of(slide);
@@ -225,12 +225,12 @@ public class AttachmentManager {
     return captureUri;
   }
 
-  public void capturePhoto(Activity activity, Recipients recipients, int requestCode) {
+  public void capturePhoto(Activity activity, int requestCode) {
     try {
       Intent captureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
       if (captureIntent.resolveActivity(activity.getPackageManager()) != null) {
         if (captureUri == null) {
-          captureUri = PersistentBlobProvider.getInstance(context).createForExternal(recipients);
+          captureUri = PersistentBlobProvider.getInstance(context).createForExternal();
         }
         Log.w(TAG, "captureUri path is " + captureUri.getPath());
         captureIntent.putExtra(MediaStore.EXTRA_OUTPUT, captureUri);

src/org/thoughtcrime/securesms/providers/PersistentBlobProvider.java

@@ -97,10 +97,9 @@ public class PersistentBlobProvider {
     });
   }
 
-  public Uri createForExternal(@NonNull Recipients recipients) throws IOException {
-    return Uri.fromFile(new File(getExternalDir(context), String.valueOf(generateId(recipients)) + ".jpg"))
+  public Uri createForExternal() throws IOException {
+    return Uri.fromFile(new File(getExternalDir(context), String.valueOf(System.currentTimeMillis()) + ".jpg"))
               .buildUpon()
-              .appendQueryParameter("unique", String.valueOf(System.currentTimeMillis()))
               .build();
   }
 
@@ -121,10 +120,6 @@ public class PersistentBlobProvider {
                           : new DecryptingPartInputStream(getFile(id), masterSecret);
   }
 
-  private int generateId(Recipients recipients) {
-    return Math.abs(Arrays.hashCode(recipients.getIds()));
-  }
-
   private File getFile(long id) {
     return new File(context.getDir("captures", Context.MODE_PRIVATE), id + ".jpg");
   }