patch 8.0.0898: can't use the alternate screen in a terminal windowv8.0.0898

Problem:    Can't use the alternate screen in a terminal window.
Solution:   Initialze the alternate screen. (Yasuhiro Matsumoto, closes
            #1957)  Add term_getaltscreen().

5 files changed, 35 insertions, 0 deletions

diff --git a/src/evalfunc.c b/src/evalfunc.c
index b5880c58d..6cb0ed7d7 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -831,6 +831,7 @@ static struct fst
 #endif
     {"tempname",	0, 0, f_tempname},
 #ifdef FEAT_TERMINAL
+    {"term_getaltscreen", 1, 1, f_term_getaltscreen},
     {"term_getattr",	2, 2, f_term_getattr},
     {"term_getcursor",	1, 1, f_term_getcursor},
     {"term_getjob",	1, 1, f_term_getjob},
diff --git a/src/libvterm/include/vterm.h b/src/libvterm/include/vterm.h
index e797dffbf..cd7b1f772 100644
--- a/src/libvterm/include/vterm.h
+++ b/src/libvterm/include/vterm.h
@@ -188,6 +188,8 @@ void vterm_keyboard_start_paste(VTerm *vt);
 void vterm_keyboard_end_paste(VTerm *vt);
 
 void vterm_mouse_move(VTerm *vt, int row, int col, VTermModifier mod);
+/* "button" is 1 for left, 2 for middle, 3 for right.
+ * Button 4 is scroll wheel down, button 5 is scroll wheel up. */
 void vterm_mouse_button(VTerm *vt, int button, int pressed, VTermModifier mod);
 
 /* ------------
@@ -302,6 +304,9 @@ typedef struct {
   int (*settermprop)(VTermProp prop, VTermValue *val, void *user);
   int (*bell)(void *user);
   int (*resize)(int rows, int cols, void *user);
+  /* A line was pushed off the top of the window.
+   * "cells[cols]" contains the cells of that line.
+   * Return value is unused. */
   int (*sb_pushline)(int cols, const VTermScreenCell *cells, void *user);
   int (*sb_popline)(int cols, VTermScreenCell *cells, void *user);
 } VTermScreenCallbacks;
@@ -320,6 +325,9 @@ void *vterm_screen_get_cbdata(VTermScreen *screen);
 void  vterm_screen_set_unrecognised_fallbacks(VTermScreen *screen, const VTermParserCallbacks *fallbacks, void *user);
 void *vterm_screen_get_unrecognised_fbdata(VTermScreen *screen);
 
+/* Enable support for using the alternate screen if "altscreen" is non-zero.
+ * Before that switching to the alternate screen won't work.
+ * Calling with "altscreen" zero has no effect. */
 void vterm_screen_enable_altscreen(VTermScreen *screen, int altscreen);
 
 typedef enum {
diff --git a/src/proto/terminal.pro b/src/proto/terminal.pro
index 7b28c2862..a004d355e 100644
--- a/src/proto/terminal.pro
+++ b/src/proto/terminal.pro
@@ -17,6 +17,7 @@ void term_change_in_curbuf(void);
 int term_get_attr(buf_T *buf, linenr_T lnum, int col);
 char_u *term_get_status_text(term_T *term);
 int set_ref_in_term(int copyID);
+void f_term_getaltscreen(typval_T *argvars, typval_T *rettv);
 void f_term_getattr(typval_T *argvars, typval_T *rettv);
 void f_term_getcursor(typval_T *argvars, typval_T *rettv);
 void f_term_getjob(typval_T *argvars, typval_T *rettv);
diff --git a/src/terminal.c b/src/terminal.c
index b1cb61fc0..e22f7bcf7 100644
--- a/src/terminal.c
+++ b/src/terminal.c
@@ -146,6 +146,8 @@ struct terminal_S {
 
     VTermPos	tl_cursor_pos;
     int		tl_cursor_visible;
+
+    int		tl_using_altscreen;
 };
 
 #define TMODE_ONCE 1	    /* CTRL-\ CTRL-N used */
@@ -1316,6 +1318,11 @@ handle_settermprop(
 	    out_flush();
 	    break;
 
+	case VTERM_PROP_ALTSCREEN:
+	    /* TODO: do anything else? */
+	    term->tl_using_altscreen = value->boolean;
+	    break;
+
 	default:
 	    break;
     }
@@ -1865,6 +1872,9 @@ create_vterm(term_T *term, int rows, int cols)
 
     /* Required to initialize most things. */
     vterm_screen_reset(screen, 1 /* hard */);
+
+    /* Allow using alternate screen. */
+    vterm_screen_enable_altscreen(screen, 1);
 }
 
 /*
@@ -1939,6 +1949,19 @@ term_get_buf(typval_T *argvars)
 }
 
 /*
+ * "term_getaltscreen(buf)" function
+ */
+    void
+f_term_getaltscreen(typval_T *argvars, typval_T *rettv)
+{
+    buf_T	*buf = term_get_buf(argvars);
+
+    if (buf == NULL)
+	return;
+    rettv->vval.v_number = buf->b_term->tl_using_altscreen;
+}
+
+/*
  * "term_getattr(attr, name)" function
  */
     void
diff --git a/src/version.c b/src/version.c
index 6a19bd147..8b112c600 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    898,
+/**/
     897,
 /**/
     896,