Support for a "pending item" in history.

Before running a command, we add the command to history, so
that if the command causes us to exit it's still captured in
history. But that command should not be considered part of
history when expanding the history within the command itself.
For example, `echo $history[1]` should be the previously
run command, not `echo $history[1]` itself.

Fixes #2028

1 files changed, 13 insertions, 7 deletions

diff --git a/history.h b/history.h
index c0e0f433..4bbdf788 100644
--- a/history.h
+++ b/history.h
@@ -61,7 +61,7 @@ private:
 
     /** Paths that we require to be valid for this item to be autosuggested */
     path_list_t required_paths;
-
+    
 public:
     const wcstring &str() const
     {
@@ -115,8 +115,8 @@ private:
     /** Private creator */
     history_t(const wcstring &pname);
 
-    /** Privately add an item */
-    void add(const history_item_t &item);
+    /** Privately add an item. If pending, the item will not be returned by history searches until a call to resolve_pending. */
+    void add(const history_item_t &item, bool pending = false);
 
     /** Destructor */
     ~history_t();
@@ -136,6 +136,9 @@ private:
     /** The index of the first new item that we have not yet written. */
     size_t first_unwritten_new_item_index;
 
+    /** Whether we have a pending item. If so, the most recently added item is ignored by item_at_index. */
+    bool has_pending_item;
+    
     /** Whether we should disable saving to the file for a time */
     uint32_t disable_automatic_save_counter;
 
@@ -208,14 +211,17 @@ public:
     /** Determines whether the history is empty. Unfortunately this cannot be const, since it may require populating the history. */
     bool is_empty(void);
 
-    /** Add a new history item to the end */
-    void add(const wcstring &str, history_identifier_t ident = 0);
+    /** Add a new history item to the end. If pending is set, the item will not be returned by item_at_index until a call to resolve_pending(). Pending items are tracked with an offset into the array of new items, so adding a non-pending item has the effect of resolving all pending items. */
+    void add(const wcstring &str, history_identifier_t ident = 0, bool pending = false);
 
     /** Remove a history item */
     void remove(const wcstring &str);
 
-    /** Add a new history item to the end */
-    void add_with_file_detection(const wcstring &str);
+    /** Add a new pending history item to the end, and then begin file detection on the items to determine which arguments are paths */
+    void add_pending_with_file_detection(const wcstring &str);
+    
+    /** Resolves any pending history items, so that they may be returned in history searches. */
+    void resolve_pending();
 
     /** Saves history */
     void save();