From 2c10a147ea0e471f12facfa11913272d42163f76 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Sat, 6 Feb 2021 11:51:58 +0100
Subject: [PATCH] url-mode: underline URLs using the color from colors.urls
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This is implemented by allocating one of the (few!) remaining bits in
the cells’ attribute struct to indicate the cell should be “URL
highlighted”.

render_cell() looks at this bit and draws an underline using the color
from colors.urls (defaults to regular3 - i.e. yellow).

A new function, url_tag_cells(), iterates the currently detected URLs
and sets the new ‘url’ attribute flag on the affected cells.

Note: this is done in a separate function to keep urls_collect() free
from as many dependencies as possible.

urls_reset() is updated to *clear* the ‘url’ flag (and thus implicitly
also results in a grid refresh, _if_ there were any URLs).

We now exit URL mode on *any* client application input. This needs to
be so since we can’t know if the URLs we previously detected are still
valid.
---
 input.c    |  1 +
 render.c   |  9 +++++++++
 terminal.c |  2 ++
 terminal.h |  3 ++-
 url-mode.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 url-mode.h |  1 +
 6 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/input.c b/input.c
index 10507aa8..7ba8e8e0 100644
--- a/input.c
+++ b/input.c
@@ -281,6 +281,7 @@ execute_binding(struct seat *seat, struct terminal *term,
             : URL_ACTION_LAUNCH;
 
         urls_collect(term, url_action);
+        urls_tag_cells(term);
         render_refresh_urls(term);
         return true;
     }
diff --git a/render.c b/render.c
index fff280fc..4e41f48a 100644
--- a/render.c
+++ b/render.c
@@ -616,6 +616,15 @@ render_cell(struct terminal *term, pixman_image_t *pix,
     if (cell->attrs.strikethrough)
         draw_strikeout(term, pix, font, &fg, x, y, cell_cols);
 
+    if (unlikely(cell->attrs.url)) {
+        pixman_color_t url_color = color_hex_to_pixman(
+            term->conf->colors.use_custom.url
+            ? term->conf->colors.url
+            : term->colors.table[3]
+            );
+        draw_underline(term, pix, font, &url_color, x, y, cell_cols);
+    }
+
 draw_cursor:
     if (has_cursor && (term->cursor_style != CURSOR_BLOCK || !term->kbd_focus))
         draw_cursor(term, cell, font, pix, &fg, &bg, x, y, cell_cols);
diff --git a/terminal.c b/terminal.c
index c67dda58..91a442ec 100644
--- a/terminal.c
+++ b/terminal.c
@@ -228,6 +228,8 @@ fdm_ptmx(struct fdm *fdm, int fd, int events, void *data)
         cursor_blink_rearm_timer(term);
     }
 
+    urls_reset(term);
+
     uint8_t buf[24 * 1024];
     ssize_t count = sizeof(buf);
 
diff --git a/terminal.h b/terminal.h
index c6a618bf..bb98efc2 100644
--- a/terminal.h
+++ b/terminal.h
@@ -40,7 +40,8 @@ struct attributes {
     uint32_t have_fg:1;
     uint32_t have_bg:1;
     uint32_t selected:2;
-    uint32_t reserved:3;
+    uint32_t url:1;
+    uint32_t reserved:2;
     uint32_t bg:24;
 };
 static_assert(sizeof(struct attributes) == 8, "bad size");
diff --git a/url-mode.c b/url-mode.c
index 8f3b867e..e418eb7e 100644
--- a/url-mode.c
+++ b/url-mode.c
@@ -7,6 +7,7 @@
 #define LOG_ENABLE_DBG 1
 #include "log.h"
 #include "grid.h"
+#include "render.h"
 #include "selection.h"
 #include "spawn.h"
 #include "terminal.h"
@@ -399,6 +400,49 @@ urls_collect(struct terminal *term, enum url_action action)
     }
 }
 
+static void
+tag_cells_for_url(struct terminal *term, const struct url *url, bool value)
+{
+    const struct coord *start = &url->start;
+    const struct coord *end = &url->end;
+
+    size_t end_r = end->row & (term->grid->num_rows - 1);
+
+    size_t r = start->row & (term->grid->num_rows - 1);
+    size_t c = start->col;
+
+    struct row *row = term->grid->rows[r];
+    row->dirty = true;
+
+    while (true) {
+        struct cell *cell = &row->cells[c];
+        cell->attrs.url = value;
+        cell->attrs.clean = 0;
+
+        if (r == end_r && c == end->col)
+            break;
+
+        if (++c >= term->cols) {
+            r = (r + 1) & (term->grid->num_rows - 1);
+            c = 0;
+
+            row = term->grid->rows[r];
+            row->dirty = true;
+        }
+    }
+}
+
+void
+urls_tag_cells(struct terminal *term)
+{
+    if (unlikely(tll_length(term->urls)) == 0)
+        return;
+
+    tll_foreach(term->urls, it)
+        tag_cells_for_url(term, &it->item, true);
+    render_refresh(term);
+}
+
 void
 urls_reset(struct terminal *term)
 {
@@ -416,10 +460,12 @@ urls_reset(struct terminal *term)
     }
 
     tll_foreach(term->urls, it) {
+        tag_cells_for_url(term, &it->item, false);
         free(it->item.url);
         free(it->item.text);
     }
     tll_free(term->urls);
 
     memset(term->url_keys, 0, sizeof(term->url_keys));
+    render_refresh(term);
 }
diff --git a/url-mode.h b/url-mode.h
index 94c1e675..6651e119 100644
--- a/url-mode.h
+++ b/url-mode.h
@@ -12,6 +12,7 @@ static inline bool urls_mode_is_active(const struct terminal *term)
 }
 
 void urls_collect(struct terminal *term, enum url_action action);
+void urls_tag_cells(struct terminal *term);
 void urls_reset(struct terminal *term);
 
 void urls_input(struct seat *seat, struct terminal *term, uint32_t key,