red: use non blocking read

hugeping · Apr 25, 2024 · 15c9154 · 15c9154
1 parent 45085d8
commit 15c9154
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Showing 2 changed files with 16 additions and 4 deletions.
diff --git a/data/lib/red/posix.lua b/data/lib/red/posix.lua
@@ -1,9 +1,11 @@
-local posix = { sighup = function() end }
+local posix = { sighup = function() end, nonblock = function() end, poll = function() return true, true end }
 
 if PLATFORM == 'Windows' or type(jit) ~= 'table' then
   return posix
 end
 
+posix.have_poll = true
+
 local ffi = require "ffi"
 ffi.cdef[[
   unsigned long signal(int signum, unsigned long);
@@ -14,12 +16,17 @@ ffi.cdef[[
   };
   int fileno(struct FILE* stream);
   int poll(struct pollfd *fds, unsigned long nfds, int timeout);
+  int fcntl(int fd, int cmd, int arg);
 ]]
 
 function posix.sighup(on)
   ffi.C.signal(13, on and 0 or 1) -- SIGPIPE, SIG_IGN
 end
 
+function posix.nonblock(f, on)
+  ffi.C.fcntl(ffi.C.fileno(f), 4, on and 2048 or 0)
+end
+
 function posix.poll(f)
   local fds = ffi.new("struct pollfd[1]")
   fds[0].fd = ffi.C.fileno(f)

diff --git a/data/lib/red/shell.lua b/data/lib/red/shell.lua
@@ -3,8 +3,7 @@ local shell = {}
 local function pipe_shell()
   local posix = require("red/posix")
   local poll, sighup = posix.poll, posix.sighup
-  local poll_mode = not not poll
-  poll = poll or function() return true end
+  local poll_mode = posix.have_poll
   local function read_sym(f)
     local t = {}
     while true do
@@ -46,7 +45,9 @@ end
 
 local function pipe_proc()
   require "std"
-  local sighup = require("red/posix").sighup
+  local posix = require("red/posix")
+  local sighup, nonblock = posix.sighup, posix.nonblock
+
   local prog, cwd = thread:read()
   if cwd and PLATFORM ~= 'Windows' then
     prog = string.format("cd %q && %s", cwd, prog)
@@ -58,7 +59,10 @@ local function pipe_proc()
   if not f then return end
   f:setvbuf 'no'
   local pre
+  nonblock(f, true)
   while true do
+    local _, ok = posix.poll(f)
+    if not ok then break end
     local chunk = f:read(512)
     if not chunk then
       if pre then
@@ -76,6 +80,7 @@ local function pipe_proc()
       thread:write(l)
     end
   end
+  nonblock(f, false)
   f:close()
   thread:write '\1eof'
 end