create reader_data_t.interruptible flag and infrastructure to make it work.

input.cpp

@@ -507,7 +507,7 @@ wint_t input_readch()
     /*
        Clear the interrupted flag
        */
-    reader_interrupted();
+    reader_reset_interrupted();
 
     /*
        Search for sequence in mapping tables

reader.cpp

@@ -323,6 +323,9 @@ public:
     /** Whether a screen reset is needed after a repaint. */
     bool screen_reset_needed;
 
+    /** Whether the reader should exit on ^C. */
+    bool interruptible;
+
     /** Constructor */
     reader_data_t() :
         allow_autosuggestion(0),
@@ -339,7 +342,8 @@ public:
         next(0),
         search_mode(0),
         repaint_needed(0),
-        screen_reset_needed(0)
+        screen_reset_needed(0),
+        interruptible(0)
     {
     }
 };
@@ -373,7 +377,7 @@ static pid_t original_pid;
 /**
    This variable is set to true by the signal handler when ^C is pressed
 */
-static int interrupted=0;
+static volatile int interrupted=0;
 
 
 /*
@@ -632,11 +636,23 @@ static void remove_duplicates(std::vector<completion_t> &l)
     l.erase(std::unique(l.begin(), l.end()), l.end());
 }
 
+
+void reader_reset_interrupted()
+{
+    interrupted = 0;
+}
+
 int reader_interrupted()
 {
     int res=interrupted;
     if (res)
+    {
         interrupted=0;
+    }
+    if (res && data && data->interruptible)
+    {
+        reader_exit(1, 0);
+    }
     return res;
 }
 
@@ -2380,6 +2396,11 @@ void reader_set_test_function(int (*f)(const wchar_t *))
     data->test_func = f;
 }
 
+void reader_set_interruptible(bool i)
+{
+    data->interruptible = i;
+}
+
 void reader_import_history_if_necessary(void)
 {
     /* Import history from bash, etc. if our current history is empty */

reader.h

@@ -111,9 +111,18 @@ void reader_set_buffer(const wcstring &b, size_t p);
 */
 size_t reader_get_cursor_pos();
 
+/**
+   Clear the interrupted flag unconditionally without handling anything. The 
+   flag could have been set e.g. when an interrupt arrived just as we were 
+   ending an earlier \c reader_readline invocation but before the 
+   \c is_interactive_read flag was cleared. 
+*/
+void reader_reset_interrupted();
+
 /**
    Return the value of the interrupted flag, which is set by the sigint
-   handler, and clear it if it was set.
+   handler, and clear it if it was set. If the current reader is interruptible,
+   call \c reader_exit(). 
 */
 int reader_interrupted();
 
@@ -181,6 +190,9 @@ void reader_set_right_prompt(const wcstring &prompt);
 /** Sets whether autosuggesting is allowed. */
 void reader_set_allow_autosuggesting(bool flag);
 
+/** Sets whether the reader should exit on ^C. */
+void reader_set_interruptible(bool flag);
+
 /**
    Returns true if the shell is exiting, 0 otherwise.
 */