Apply Scrollback patch

Homepage link: https://st.suckless.org/patches/scrollback/
Patch link:
    https://st.suckless.org/patches/scrollback/st-scrollback-20200419-72e3f6c.diff
    https://st.suckless.org/patches/scrollback/st-scrollback-mouse-20191024-a2c479c.diff
    https://st.suckless.org/patches/scrollback/st-scrollback-mouse-altscreen-20200416-5703aa0.diff
    https://st.suckless.org/patches/scrollback/st-scrollback-mouse-increment-0.8.2.diff
Additional info:
+ patch applied because I'm planning on ditching tmux, which currently
  provides this functionality;
+ patches applied manually.

5 files changed, 120 insertions, 28 deletions

diff --git a/config.def.h b/config.def.h
index 12ba690..c2f3756 100644
--- a/config.def.h
+++ b/config.def.h
@@ -166,8 +166,11 @@ static uint forcemousemod = ShiftMask;
  * Internal mouse shortcuts.
  * Beware that overloading Button1 will disable the selection.
  */
+const unsigned int mousescrollinc = 1;
 static MouseShortcut mshortcuts[] = {
         /* mask                 button   function        argument       release */
+    { XK_ANY_MOD,           Button4, kscrollup,      {.i = mousescrollinc},      0, /* !alt */ -1 },
+    { XK_ANY_MOD,           Button5, kscrolldown,    {.i = mousescrollinc},      0, /* !alt */ -1 },
         { XK_ANY_MOD,           Button2, selpaste,       {.i = 0},      1 },
         { XK_ANY_MOD,           Button4, ttysend,        {.s = "\031"} },
         { XK_ANY_MOD,           Button5, ttysend,        {.s = "\005"} },
@@ -191,6 +194,8 @@ static Shortcut shortcuts[] = {
         { TERMMOD,              XK_Y,           selpaste,       {.i =  0} },
         { ShiftMask,            XK_Insert,      selpaste,       {.i =  0} },
         { TERMMOD,              XK_Num_Lock,    numlock,        {.i =  0} },
+    { ShiftMask,            XK_Page_Up,     kscrollup,      {.i = -1} },
+    { ShiftMask,            XK_Page_Down,   kscrolldown,    {.i = -1} },
 };
 
 /*
diff --git a/config.h b/config.h
index 12ba690..c2f3756 100644
--- a/config.h
+++ b/config.h
@@ -166,8 +166,11 @@ static uint forcemousemod = ShiftMask;
  * Internal mouse shortcuts.
  * Beware that overloading Button1 will disable the selection.
  */
+const unsigned int mousescrollinc = 1;
 static MouseShortcut mshortcuts[] = {
         /* mask                 button   function        argument       release */
+    { XK_ANY_MOD,           Button4, kscrollup,      {.i = mousescrollinc},      0, /* !alt */ -1 },
+    { XK_ANY_MOD,           Button5, kscrolldown,    {.i = mousescrollinc},      0, /* !alt */ -1 },
         { XK_ANY_MOD,           Button2, selpaste,       {.i = 0},      1 },
         { XK_ANY_MOD,           Button4, ttysend,        {.s = "\031"} },
         { XK_ANY_MOD,           Button5, ttysend,        {.s = "\005"} },
@@ -191,6 +194,8 @@ static Shortcut shortcuts[] = {
         { TERMMOD,              XK_Y,           selpaste,       {.i =  0} },
         { ShiftMask,            XK_Insert,      selpaste,       {.i =  0} },
         { TERMMOD,              XK_Num_Lock,    numlock,        {.i =  0} },
+    { ShiftMask,            XK_Page_Up,     kscrollup,      {.i = -1} },
+    { ShiftMask,            XK_Page_Down,   kscrolldown,    {.i = -1} },
 };
 
 /*
diff --git a/st.c b/st.c
index 3e48410..83681c1 100644
--- a/st.c
+++ b/st.c
@@ -35,13 +35,17 @@
 #define ESC_ARG_SIZ   16
 #define STR_BUF_SIZ   ESC_BUF_SIZ
 #define STR_ARG_SIZ   ESC_ARG_SIZ
+#define HISTSIZE      5000
 
 /* macros */
 #define IS_SET(flag)            ((term.mode & (flag)) != 0)
 #define ISCONTROLC0(c)          (BETWEEN(c, 0, 0x1f) || (c) == '\177')
 #define ISCONTROLC1(c)          (BETWEEN(c, 0x80, 0x9f))
 #define ISCONTROL(c)            (ISCONTROLC0(c) || ISCONTROLC1(c))
-#define ISDELIM(u)              (u && wcschr(worddelimiters, u))
+#define ISDELIM(u)                  (u && wcschr(worddelimiters, u))
+#define TLINE(y)            ((y) < term.scr ? term.hist[((y) + term.histi - \
+                            term.scr + HISTSIZE + 1) % HISTSIZE] : \
+                            term.line[(y) - term.scr])
 
 enum term_mode {
         MODE_WRAP        = 1 << 0,
@@ -117,6 +121,9 @@ typedef struct {
         int col;      /* nb col */
         Line *line;   /* screen */
         Line *alt;    /* alternate screen */
+    Line hist[HISTSIZE]; /* history buffer */
+    int histi;    /* history index */
+    int scr;      /* scroll back */
         int *dirty;   /* dirtyness of lines */
         TCursor c;    /* cursor */
         int ocx;      /* old cursor col */
@@ -185,8 +192,8 @@ static void tnewline(int);
 static void tputtab(int);
 static void tputc(Rune);
 static void treset(void);
-static void tscrollup(int, int);
-static void tscrolldown(int, int);
+static void tscrollup(int, int, int);
+static void tscrolldown(int, int, int);
 static void tsetattr(int *, int);
 static void tsetchar(Rune, Glyph *, int, int);
 static void tsetdirt(int, int);
@@ -414,10 +421,10 @@ tlinelen(int y)
 {
         int i = term.col;
 
-        if (term.line[y][i - 1].mode & ATTR_WRAP)
+    if (TLINE(y)[i - 1].mode & ATTR_WRAP)
                 return i;
 
-        while (i > 0 && term.line[y][i - 1].u == ' ')
+    while (i > 0 && TLINE(y)[i - 1].u == ' ')
                 --i;
 
         return i;
@@ -526,7 +533,7 @@ selsnap(int *x, int *y, int direction)
                  * Snap around if the word wraps around at the end or
                  * beginning of a line.
                  */
-                prevgp = &term.line[*y][*x];
+        prevgp = &TLINE(*y)[*x];
                 prevdelim = ISDELIM(prevgp->u);
                 for (;;) {
                         newx = *x + direction;
@@ -541,14 +548,14 @@ selsnap(int *x, int *y, int direction)
                                         yt = *y, xt = *x;
                                 else
                                         yt = newy, xt = newx;
-                                if (!(term.line[yt][xt].mode & ATTR_WRAP))
+                if (!(TLINE(yt)[xt].mode & ATTR_WRAP))
                                         break;
                         }
 
                         if (newx >= tlinelen(newy))
                                 break;
 
-                        gp = &term.line[newy][newx];
+            gp = &TLINE(newy)[newx];
                         delim = ISDELIM(gp->u);
                         if (!(gp->mode & ATTR_WDUMMY) && (delim != prevdelim
                                         || (delim && gp->u != prevgp->u)))
@@ -569,14 +576,14 @@ selsnap(int *x, int *y, int direction)
                 *x = (direction < 0) ? 0 : term.col - 1;
                 if (direction < 0) {
                         for (; *y > 0; *y += direction) {
-                                if (!(term.line[*y-1][term.col-1].mode
+                if (!(TLINE(*y-1)[term.col-1].mode
                                                 & ATTR_WRAP)) {
                                         break;
                                 }
                         }
                 } else if (direction > 0) {
                         for (; *y < term.row-1; *y += direction) {
-                                if (!(term.line[*y][term.col-1].mode
+                if (!(TLINE(*y)[term.col-1].mode
                                                 & ATTR_WRAP)) {
                                         break;
                                 }
@@ -607,13 +614,13 @@ getsel(void)
                 }
 
                 if (sel.type == SEL_RECTANGULAR) {
-                        gp = &term.line[y][sel.nb.x];
+            gp = &TLINE(y)[sel.nb.x];
                         lastx = sel.ne.x;
                 } else {
-                        gp = &term.line[y][sel.nb.y == y ? sel.nb.x : 0];
+            gp = &TLINE(y)[sel.nb.y == y ? sel.nb.x : 0];
                         lastx = (sel.ne.y == y) ? sel.ne.x : term.col-1;
                 }
-                last = &term.line[y][MIN(lastx, linelen-1)];
+        last = &TLINE(y)[MIN(lastx, linelen-1)];
                 while (last >= gp && last->u == ' ')
                         --last;
 
@@ -836,6 +843,9 @@ void
 ttywrite(const char *s, size_t n, int may_echo)
 {
         const char *next;
+    Arg arg = (Arg) { .i = term.scr };
+
+    kscrolldown(&arg);
 
         if (may_echo && IS_SET(MODE_ECHO))
                 twrite(s, n, 1);
@@ -1035,6 +1045,12 @@ tnew(int col, int row)
         treset();
 }
 
+int
+tisaltscr(void)
+{
+   return IS_SET(MODE_ALTSCREEN);
+}
+
 void
 tswapscreen(void)
 {
@@ -1047,13 +1063,53 @@ tswapscreen(void)
 }
 
 void
-tscrolldown(int orig, int n)
+kscrolldown(const Arg* a)
+{
+   int n = a->i;
+
+   if (n < 0)
+       n = term.row + n;
+
+   if (n > term.scr)
+       n = term.scr;
+
+   if (term.scr > 0) {
+       term.scr -= n;
+       selscroll(0, -n);
+       tfulldirt();
+   }
+}
+
+void
+kscrollup(const Arg* a)
+{
+   int n = a->i;
+
+   if (n < 0)
+       n = term.row + n;
+
+   if (term.scr <= HISTSIZE-n) {
+       term.scr += n;
+       selscroll(0, n);
+       tfulldirt();
+   }
+}
+
+void
+tscrolldown(int orig, int n, int copyhist)
 {
         int i;
         Line temp;
 
         LIMIT(n, 0, term.bot-orig+1);
 
+    if (copyhist) {
+        term.histi = (term.histi - 1 + HISTSIZE) % HISTSIZE;
+        temp = term.hist[term.histi];
+        term.hist[term.histi] = term.line[term.bot];
+        term.line[term.bot] = temp;
+    }
+ 
         tsetdirt(orig, term.bot-n);
         tclearregion(0, term.bot-n+1, term.col-1, term.bot);
 
@@ -1063,17 +1119,28 @@ tscrolldown(int orig, int n)
                 term.line[i-n] = temp;
         }
 
-        selscroll(orig, n);
+    if (term.scr == 0)
+        selscroll(orig, n);
 }
 
 void
-tscrollup(int orig, int n)
+tscrollup(int orig, int n, int copyhist)
 {
         int i;
         Line temp;
 
         LIMIT(n, 0, term.bot-orig+1);
 
+    if (copyhist) {
+        term.histi = (term.histi + 1) % HISTSIZE;
+        temp = term.hist[term.histi];
+        term.hist[term.histi] = term.line[orig];
+        term.line[orig] = temp;
+    }
+ 
+    if (term.scr > 0 && term.scr < HISTSIZE)
+        term.scr = MIN(term.scr + n, HISTSIZE-1);
+ 
         tclearregion(0, orig, term.col-1, orig+n-1);
         tsetdirt(orig+n, term.bot);
 
@@ -1083,7 +1150,8 @@ tscrollup(int orig, int n)
                 term.line[i+n] = temp;
         }
 
-        selscroll(orig, -n);
+    if (term.scr == 0)
+        selscroll(orig, -n);
 }
 
 void
@@ -1122,7 +1190,7 @@ tnewline(int first_col)
         int y = term.c.y;
 
         if (y == term.bot) {
-                tscrollup(term.top, 1);
+                tscrollup(term.top, 1, 1);
         } else {
                 y++;
         }
@@ -1287,14 +1355,14 @@ void
 tinsertblankline(int n)
 {
         if (BETWEEN(term.c.y, term.top, term.bot))
-                tscrolldown(term.c.y, n);
+                tscrolldown(term.c.y, n, 0);
 }
 
 void
 tdeleteline(int n)
 {
         if (BETWEEN(term.c.y, term.top, term.bot))
-                tscrollup(term.c.y, n);
+                tscrollup(term.c.y, n, 0);
 }
 
 int32_t
@@ -1725,11 +1793,11 @@ csihandle(void)
                 break;
         case 'S': /* SU -- Scroll <n> line up */
                 DEFAULT(csiescseq.arg[0], 1);
-                tscrollup(term.top, csiescseq.arg[0]);
+                tscrollup(term.top, csiescseq.arg[0], 0);
                 break;
         case 'T': /* SD -- Scroll <n> line down */
                 DEFAULT(csiescseq.arg[0], 1);
-                tscrolldown(term.top, csiescseq.arg[0]);
+                tscrolldown(term.top, csiescseq.arg[0], 0);
                 break;
         case 'L': /* IL -- Insert <n> blank lines */
                 DEFAULT(csiescseq.arg[0], 1);
@@ -2235,7 +2303,7 @@ eschandle(uchar ascii)
                 return 0;
         case 'D': /* IND -- Linefeed */
                 if (term.c.y == term.bot) {
-                        tscrollup(term.top, 1);
+                        tscrollup(term.top, 1, 1);
                 } else {
                         tmoveto(term.c.x, term.c.y+1);
                 }
@@ -2248,7 +2316,7 @@ eschandle(uchar ascii)
                 break;
         case 'M': /* RI -- Reverse index */
                 if (term.c.y == term.top) {
-                        tscrolldown(term.top, 1);
+                        tscrolldown(term.top, 1, 1);
                 } else {
                         tmoveto(term.c.x, term.c.y-1);
                 }
@@ -2469,7 +2537,7 @@ twrite(const char *buf, int buflen, int show_ctrl)
 void
 tresize(int col, int row)
 {
-        int i;
+        int i, j;
         int minrow = MIN(row, term.row);
         int mincol = MIN(col, term.col);
         int *bp;
@@ -2506,6 +2574,14 @@ tresize(int col, int row)
         term.dirty = xrealloc(term.dirty, row * sizeof(*term.dirty));
         term.tabs = xrealloc(term.tabs, col * sizeof(*term.tabs));
 
+    for (i = 0; i < HISTSIZE; i++) {
+        term.hist[i] = xrealloc(term.hist[i], col * sizeof(Glyph));
+        for (j = mincol; j < col; j++) {
+            term.hist[i][j] = term.c.attr;
+            term.hist[i][j].u = ' ';
+        }
+    }
+
         /* resize each row to new width, zero-pad if needed */
         for (i = 0; i < minrow; i++) {
                 term.line[i] = xrealloc(term.line[i], col * sizeof(Glyph));
@@ -2563,7 +2639,7 @@ drawregion(int x1, int y1, int x2, int y2)
                         continue;
 
                 term.dirty[y] = 0;
-                xdrawline(term.line[y], x1, y, x2);
+        xdrawline(TLINE(y), x1, y, x2);
         }
 }
 
@@ -2584,8 +2660,9 @@ draw(void)
                 cx--;
 
         drawregion(0, 0, term.col, term.row);
-        xdrawcursor(cx, term.c.y, term.line[term.c.y][cx],
-                        term.ocx, term.ocy, term.line[term.ocy][term.ocx]);
+    if (term.scr == 0)
+            xdrawcursor(cx, term.c.y, term.line[term.c.y][cx],
+                    term.ocx, term.ocy, term.line[term.ocy][term.ocx]);
         term.ocx = cx, term.ocy = term.c.y;
         xfinishdraw();
         xximspot(term.ocx, term.ocy);
diff --git a/st.h b/st.h
index a1928ca..f9ad815 100644
--- a/st.h
+++ b/st.h
@@ -81,12 +81,15 @@ void die(const char *, ...);
 void redraw(void);
 void draw(void);
 
+void kscrolldown(const Arg *);
+void kscrollup(const Arg *);
 void printscreen(const Arg *);
 void printsel(const Arg *);
 void sendbreak(const Arg *);
 void toggleprinter(const Arg *);
 
 int tattrset(int);
+int tisaltscr(void);
 void tnew(int, int);
 void tresize(int, int);
 void tsetdirtattr(int);
diff --git a/x.c b/x.c
index 57f6f1b..18d258e 100644
--- a/x.c
+++ b/x.c
@@ -34,6 +34,7 @@ typedef struct {
         void (*func)(const Arg *);
         const Arg arg;
         uint  release;
+    int  altscrn;  /* 0: don't care, -1: not alt screen, 1: alt screen */
 } MouseShortcut;
 
 typedef struct {
@@ -434,6 +435,7 @@ mouseaction(XEvent *e, uint release)
         for (ms = mshortcuts; ms < mshortcuts + LEN(mshortcuts); ms++) {
                 if (ms->release == release &&
                     ms->button == e->xbutton.button &&
+            (!ms->altscrn || (ms->altscrn == (tisaltscr() ? 1 : -1))) &&
                     (match(ms->mod, e->xbutton.state) ||  /* exact or forced */
                      match(ms->mod, e->xbutton.state & ~forcemousemod))) {
                         ms->func(&(ms->arg));