Exclude folders Trash, Spam, and Outbox from "All messages"

src/com/fsck/k9/Account.java

@@ -1856,6 +1856,30 @@ public class Account implements BaseAccount {
         search.or(new SearchCondition(Searchfield.FOLDER, Attribute.EQUALS, getInboxFolderName()));
     }
 
+    /**
+     * Modify the supplied {@link LocalSearch} instance to exclude "unwanted" folders.
+     *
+     * <p>
+     * Currently the following folders are excluded:
+     * <ul>
+     *   <li>Trash</li>
+     *   <li>Spam</li>
+     *   <li>Outbox</li>
+     * </ul>
+     * The Inbox will always be included even if one of the special folders is configured to point
+     * to the Inbox.
+     * </p>
+     *
+     * @param search
+     *         The {@code LocalSearch} instance to modify.
+     */
+    public void excludeUnwantedFolders(LocalSearch search) {
+        excludeSpecialFolder(search, getTrashFolderName());
+        excludeSpecialFolder(search, getSpamFolderName());
+        excludeSpecialFolder(search, getOutboxFolderName());
+        search.or(new SearchCondition(Searchfield.FOLDER, Attribute.EQUALS, getInboxFolderName()));
+    }
+
     private void excludeSpecialFolder(LocalSearch search, String folderName) {
         if (!K9.FOLDER_NONE.equals(folderName)) {
             search.and(Searchfield.FOLDER, folderName, Attribute.NOT_EQUALS);

src/com/fsck/k9/search/SqlQueryBuilder.java

@@ -42,8 +42,14 @@ public class SqlQueryBuilder {
                 case SEARCHABLE: {
                     switch (account.getSearchableFolders()) {
                         case ALL: {
-                            // Dummy condition, always select
+                            // Create temporary LocalSearch object so we can use...
-                            query.append("1");
+                            LocalSearch tempSearch = new LocalSearch();
+                            // ...the helper methods in Account to create the necessary conditions
+                            // to exclude "unwanted" folders.
+                            account.excludeUnwantedFolders(tempSearch);
+
+                            buildWhereClauseInternal(account, tempSearch.getConditions(), query,
+                                    selectionArgs);
                             break;
                         }
                         case DISPLAYABLE: {