add tty.has_color24

1 files changed, 52 insertions, 3 deletions

diff --git a/xmake/core/base/tty.lua b/xmake/core/base/tty.lua
index 1ccaedae1..fd7de2175 100644
--- a/xmake/core/base/tty.lua
+++ b/xmake/core/base/tty.lua
@@ -40,7 +40,7 @@ end
 
 -- get colorterm setting
 --
--- COLORTERM: color8, color256, truecolor, nocolor
+-- COLORTERM: 8color, 256color, truecolor, nocolor
 --
 function tty._colorterm()
     local colorterm = tty._COLORTERM
@@ -229,7 +229,9 @@ function tty.has_color8()
             local colorterm = tty._colorterm()
             if colorterm == "nocolor" then
                 has_color8 = false
-            elseif colorterm == "color8" or colorterm == "color256" or colorterm == "truecolor" then
+            elseif colorterm and colorterm:find("8color", 1, true) then
+                has_color8 = true
+            elseif tty.has_color256() or tty.has_color24() then
                 has_color8 = true
             end
         end
@@ -274,7 +276,9 @@ function tty.has_color256()
             local colorterm = tty._colorterm()
             if colorterm == "nocolor" then
                 has_color256 = false
-            elseif colorterm == "color256" or colorterm == "truecolor" then
+            elseif colorterm and colorterm:find("256color", 1, true) then
+                has_color256 = true
+            elseif tty.has_color24() then
                 has_color256 = true
             end
         end
@@ -306,5 +310,50 @@ function tty.has_color256()
     return has_color256
 end
 
+-- has 24bits true color?
+--
+-- There's no reliable way, and ncurses/terminfo's maintainer expressed he has no intent on introducing support.
+-- S-Lang author added a check for $COLORTERM containing either "truecolor" or "24bit" (case sensitive).
+-- In turn, VTE, Konsole and iTerm2 set this variable to "truecolor" (it's been there in VTE for a while,
+-- it's relatively new and maybe still git-only in Konsole and iTerm2).
+--
+-- This is obviously not a reliable method, and is not forwarded via sudo, ssh etc. However, whenever it errs,
+-- it errs on the safe side: does not advertise support whereas it's actually supported.
+-- App developers can freely choose to check for this same variable, or introduce their own method
+-- (e.g. an option in their config file), whichever matches better the overall design of the given app.
+-- Checking $COLORTERM is recommended though, since that would lead to a more unique desktop experience
+-- where the user has to set one variable only and it takes effect across all the apps, rather than something
+-- separately for each app.
+--
+function tty.has_color24()
+
+    local has_color24 = tty._HAS_COLOR24
+    if has_color24 == nil then
+
+        -- detect it from $COLORTERM
+        if has_color24 == nil then
+            local colorterm = tty._colorterm()
+            if colorterm == "nocolor" then
+                has_color24 = false
+            elseif colorterm and (colorterm:find("truecolor", 1, true) or colorterm:find("24bit", 1, true)) then
+                has_color24 = true
+            end
+        end
+
+        -- detect it from $TERM
+        local term = tty.term()
+        local term_env = os.getenv("TERM")
+        if has_color256 == nil then
+            if term == "vstudio" then
+                has_color256 = false
+            elseif term_env and (term_env:find("truecolor", 1, true) or term_env:find("24bit", 1, true)) then
+                has_color256 = true
+            end
+        end
+        tty._HAS_COLOR24 = has_color24 or false
+    end
+    return has_color24
+end
+
 -- return module
 return tty