Improve our display of inline images in HTML mail to not also offer

themselves up for download.

To do so, we need to start storing the original content-id and
content-disposition for attachments - this includes a database upgrade.

Based on a patch from @achen.code

src/com/fsck/k9/activity/MessageView.java

@@ -11,6 +11,8 @@ import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Set;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 import org.apache.commons.io.IOUtils;
 
@@ -1887,18 +1889,14 @@ public class MessageView extends K9Activity implements OnClickListener
 
         // Inline parts with a content-id are almost certainly components of an HTML message
         // not attachments. Don't show attachment download buttons for them.
-        //
-        // TODO: This code won't work until we correct attachment storage
 
-        if ("inline".equalsIgnoreCase(MimeUtility.getHeaderParameter(contentDisposition, null))
+        if ( contentDisposition != null &&
-                && part.getHeader("Content-Id") != null)
+                MimeUtility.getHeaderParameter(contentDisposition, null).matches("^(?i:inline)")
+                && part.getHeader("Content-ID") != null)
         {
             return;
         }
 
-
-
-
         if (name == null)
         {
             name = MimeUtility.getHeaderParameter(contentDisposition, "filename");
@@ -2140,22 +2138,15 @@ public class MessageView extends K9Activity implements OnClickListener
                         }
                     });
 
-                    // TODO: Only check for external (non inline) images
+                    // If the message contains external pictures and the "Show pictures"
-                    final boolean hasPictures = text.contains("<img");
+                    // button wasn't already pressed, see if the user's preferences has us
-
+                    // showing them anyway.
-                    // If the message contains pictures and the "Show pictures"
+                    if ( hasExternalImages(MimeUtility.unfoldAndDecode(text))
-                    // button wasn't already pressed...
+                            && (mShowPictures == false))
-                    if (hasPictures && (mShowPictures == false))
                     {
-                        boolean forceShowPictures = false;
                         if ((account.getShowPictures() == Account.ShowPictures.ALWAYS) ||
                                 ((account.getShowPictures() == Account.ShowPictures.ONLY_FROM_CONTACTS) &&
                                 mContacts.isInContacts(message.getFrom()[0].getAddress())))
-                        {
-                            forceShowPictures = true;
-                        }
-
-                        if (forceShowPictures)
                         {
                             onShowPictures();
                         }
@@ -2188,6 +2179,21 @@ public class MessageView extends K9Activity implements OnClickListener
             }
         }//loadMessageForViewBodyAvailable
 
+        private static final String IMG_SRC_REGEX = "(?is:<img[^>]+src\\s*=\\s*['\"]?([a-z]+)\\:)";
+        private boolean hasExternalImages(final String message) {
+            Pattern mImgPattern = Pattern.compile(IMG_SRC_REGEX);
+            Matcher mImgMatches = mImgPattern.matcher(message);
+            while(mImgMatches.find()) {
+                if(!mImgMatches.group(1).equals("content")) {
+                    if (K9.DEBUG)
+                        Log.d(K9.LOG_TAG, "External images found.");
+                    return true;
+                }
+            }
+            if (K9.DEBUG)
+                Log.d(K9.LOG_TAG, "No external images.");
+            return false;
+        }
 
         @Override
         public void loadMessageForViewFailed(Account account, String folder, String uid,

src/com/fsck/k9/mail/store/LocalStore.java

@@ -44,7 +44,7 @@ public class LocalStore extends Store implements Serializable
      */
     private static final String[] EMPTY_STRING_ARRAY = new String[0];
 
-    private static final int DB_VERSION = 35;
+    private static final int DB_VERSION = 37;
     private static final Flag[] PERMANENT_FLAGS = { Flag.DELETED, Flag.X_DESTROYED, Flag.SEEN, Flag.FLAGGED };
 
     private String mPath;
@@ -62,6 +62,8 @@ public class LocalStore extends Store implements Serializable
         HEADERS_TO_SAVE.add("From");
         HEADERS_TO_SAVE.add("In-Reply-To");
         HEADERS_TO_SAVE.add("References");
+        HEADERS_TO_SAVE.add("Content-ID");
+        HEADERS_TO_SAVE.add("Content-Disposition");
         HEADERS_TO_SAVE.add("X-User-Agent");
     }
     /*
@@ -164,7 +166,7 @@ public class LocalStore extends Store implements Serializable
                 mDb.execSQL("DROP TABLE IF EXISTS attachments");
                 mDb.execSQL("CREATE TABLE attachments (id INTEGER PRIMARY KEY, message_id INTEGER,"
                             + "store_data TEXT, content_uri TEXT, size INTEGER, name TEXT,"
-                            + "mime_type TEXT)");
+                            + "mime_type TEXT, content_id TEXT, content_disposition TEXT)");
 
                 mDb.execSQL("DROP TABLE IF EXISTS pending_commands");
                 mDb.execSQL("CREATE TABLE pending_commands " +
@@ -244,6 +246,28 @@ public class LocalStore extends Store implements Serializable
                         Log.e(K9.LOG_TAG, "Unable to get rid of obsolete flag X_NO_SEEN_INFO", e);
                     }
                 }
+                if (mDb.getVersion() < 36)
+                {
+                    try
+                    {
+                        mDb.execSQL("ALTER TABLE attachments ADD content_id TEXT");
+                    }
+                    catch (SQLiteException e)
+                    {
+                        Log.e(K9.LOG_TAG, "Unable to add content_id column to attachments");
+                    }
+                }
+                if (mDb.getVersion() < 37)
+                {
+                    try
+                    {
+                        mDb.execSQL("ALTER TABLE attachments ADD content_disposition TEXT");
+                    }
+                    catch (SQLiteException e)
+                    {
+                        Log.e(K9.LOG_TAG, "Unable to add content_disposition column to attachments");
+                    }
+                }
 
 
             }
@@ -1391,7 +1415,9 @@ public class LocalStore extends Store implements Serializable
                                          "name",
                                          "mime_type",
                                          "store_data",
-                                         "content_uri"
+                                         "content_uri",
+                                        "content_id",
+                                        "content_disposition"
                                      },
                                      "message_id = ?",
                                      new String[] { Long.toString(localMessage.mId) },
@@ -1407,7 +1433,15 @@ public class LocalStore extends Store implements Serializable
                             String type = cursor.getString(3);
                             String storeData = cursor.getString(4);
                             String contentUri = cursor.getString(5);
+                            String contentId = cursor.getString(6);
+                            String contentDisposition = cursor.getString(7);
                             Body body = null;
+
+                            if (contentDisposition == null )
+                            {
+                                contentDisposition = "attachment";
+                            }
+
                             if (contentUri != null)
                             {
                                 body = new LocalAttachmentBody(Uri.parse(contentUri), mApplication);
@@ -1419,10 +1453,12 @@ public class LocalStore extends Store implements Serializable
                                                        name));
                             bp.setHeader(MimeHeader.HEADER_CONTENT_TRANSFER_ENCODING, "base64");
                             bp.setHeader(MimeHeader.HEADER_CONTENT_DISPOSITION,
-                                         String.format("attachment;\n filename=\"%s\";\n size=%d",
+                                         String.format("%s;\n filename=\"%s\";\n size=%d",
+                                                       contentDisposition,
                                                        name,
                                                        size));
 
+                            bp.setHeader(MimeHeader.HEADER_CONTENT_ID, contentId);
                             /*
                              * HEADER_ANDROID_ATTACHMENT_STORE_DATA is a custom header we add to that
                              * we can later pull the attachment from the remote store if neccesary.
@@ -2040,6 +2076,8 @@ public class LocalStore extends Store implements Serializable
                 cv.put("size", size);
                 cv.put("name", name);
                 cv.put("mime_type", attachment.getMimeType());
+                cv.put("content_id", contentId);
+                cv.put("content_disposition", contentDisposition);
 
                 attachmentId = mDb.insert("attachments", "message_id", cv);
             }