+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#ifndef TOP_H
+#define TOP_H
+
+#include "gdbsupport/buffer.h"
+#include "gdbsupport/event-loop.h"
+#include "gdbsupport/next-iterator.h"
+#include "value.h"
+
+struct tl_interp_info;
+
+/* Prompt state. */
+
+enum prompt_state
+{
+ /* The command line is blocked simulating synchronous execution.
+ This is used to implement the foreground execution commands
+ ('run', 'continue', etc.). We won't display the prompt and
+ accept further commands until the execution is actually over. */
+ PROMPT_BLOCKED,
+
+ /* The command finished; display the prompt before returning back to
+ the top level. */
+ PROMPT_NEEDED,
+
+ /* We've displayed the prompt already, ready for input. */
+ PROMPTED,
+};
+
+/* All about a user interface instance. Each user interface has its
+ own I/O files/streams, readline state, its own top level
+ interpreter (for the main UI, this is the interpreter specified
+ with -i on the command line) and secondary interpreters (for
+ interpreter-exec ...), etc. There's always one UI associated with
+ stdin/stdout/stderr, but the user can create secondary UIs, for
+ example, to create a separate MI channel on its own stdio
+ streams. */
+
+struct ui
+{
+ /* Create a new UI. */
+ ui (FILE *instream, FILE *outstream, FILE *errstream);
+ ~ui ();
+
+ DISABLE_COPY_AND_ASSIGN (ui);
+
+ /* Pointer to next in singly-linked list. */
+ struct ui *next;
+
+ /* Convenient handle (UI number). Unique across all UIs. */
+ int num;
+
+ /* The UI's command line buffer. This is to used to accumulate
+ input until we have a whole command line. */
+ struct buffer line_buffer;
+
+ /* The callback used by the event loop whenever an event is detected
+ on the UI's input file descriptor. This function incrementally
+ builds a buffer where it accumulates the line read up to the
+ point of invocation. In the special case in which the character
+ read is newline, the function invokes the INPUT_HANDLER callback
+ (see below). */
+ void (*call_readline) (gdb_client_data);
+
+ /* The function to invoke when a complete line of input is ready for
+ processing. */
+ void (*input_handler) (gdb::unique_xmalloc_ptr<char> &&);
+
+ /* True if this UI is using the readline library for command
+ editing; false if using GDB's own simple readline emulation, with
+ no editing support. */
+ int command_editing;
+
+ /* Each UI has its own independent set of interpreters. */
+ struct ui_interp_info *interp_info;
+
+ /* True if the UI is in async mode, false if in sync mode. If in
+ sync mode, a synchronous execution command (e.g, "next") does not
+ return until the command is finished. If in async mode, then
+ running a synchronous command returns right after resuming the
+ target. Waiting for the command's completion is later done on
+ the top event loop. For the main UI, this starts out disabled,
+ until all the explicit command line arguments (e.g., `gdb -ex
+ "start" -ex "next"') are processed. */
+ int async;
+
+ /* The number of nested readline secondary prompts that are
+ currently active. */
+ int secondary_prompt_depth;
+
+ /* The UI's stdin. Set to stdin for the main UI. */
+ FILE *stdin_stream;
+
+ /* stdio stream that command input is being read from. Set to stdin
+ normally. Set by source_command to the file we are sourcing.
+ Set to NULL if we are executing a user-defined command or
+ interacting via a GUI. */
+ FILE *instream;
+ /* Standard output stream. */
+ FILE *outstream;
+ /* Standard error stream. */
+ FILE *errstream;
+
+ /* The file descriptor for the input stream, so that we can register
+ it with the event loop. */
+ int input_fd;
+
+ /* Whether ISATTY returns true on input_fd. Cached here because
+ quit_force needs to know this _after_ input_fd might be
+ closed. */
+ int input_interactive_p;
+
+ /* See enum prompt_state's description. */
+ enum prompt_state prompt_state;
+
+ /* The fields below that start with "m_" are "private". They're
+ meant to be accessed through wrapper macros that make them look
+ like globals. */
+
+ /* The ui_file streams. */
+ /* Normal results */
+ struct ui_file *m_gdb_stdout;
+ /* Input stream */
+ struct ui_file *m_gdb_stdin;
+ /* Serious error notifications */
+ struct ui_file *m_gdb_stderr;
+ /* Log/debug/trace messages that should bypass normal stdout/stderr
+ filtering. For moment, always call this stream using
+ *_unfiltered. In the very near future that restriction shall be
+ removed - either call shall be unfiltered. (cagney 1999-06-13). */
+ struct ui_file *m_gdb_stdlog;
+
+ /* The current ui_out. */
+ struct ui_out *m_current_uiout;
+};
+
+/* The main UI. This is the UI that is bound to stdin/stdout/stderr.
+ It always exists and is created automatically when GDB starts
+ up. */
+extern struct ui *main_ui;
+
+/* The current UI. */
+extern struct ui *current_ui;
+
+/* The list of all UIs. */
+extern struct ui *ui_list;
+
+/* State for SWITCH_THRU_ALL_UIS. */
+class switch_thru_all_uis
+{
+public:
+
+ switch_thru_all_uis () : m_iter (ui_list), m_save_ui (¤t_ui)
+ {
+ current_ui = ui_list;
+ }
+
+ /* If done iterating, return true; otherwise return false. */
+ bool done () const
+ {
+ return m_iter == NULL;
+ }
+
+ /* Move to the next UI, setting current_ui if iteration is not yet
+ complete. */
+ void next ()
+ {
+ m_iter = m_iter->next;
+ if (m_iter != NULL)
+ current_ui = m_iter;
+ }
+
+ private:
+
+ /* No need for these. They are intentionally not defined
+ anywhere. */
+ switch_thru_all_uis &operator= (const switch_thru_all_uis &);
+ switch_thru_all_uis (const switch_thru_all_uis &);
+
+ /* Used to iterate through the UIs. */
+ struct ui *m_iter;
+
+ /* Save and restore current_ui. */
+ scoped_restore_tmpl<struct ui *> m_save_ui;
+};
+
+ /* Traverse through all UI, and switch the current UI to the one
+ being iterated. */
+#define SWITCH_THRU_ALL_UIS() \
+ for (switch_thru_all_uis stau_state; !stau_state.done (); stau_state.next ())
+
+/* An adapter that can be used to traverse over all UIs. */
+static inline
+next_adapter<ui> all_uis ()
+{
+ return next_adapter<ui> (ui_list);
+}
+
+/* Register the UI's input file descriptor in the event loop. */
+extern void ui_register_input_event_handler (struct ui *ui);
+
+/* Unregister the UI's input file descriptor from the event loop. */
+extern void ui_unregister_input_event_handler (struct ui *ui);