First Commit

toolchain/lib/path.lua

@@ -0,0 +1,124 @@
+-- path.lua -- minimal self-contained filesystem helpers for zeta-makepkg.
+--
+-- Deliberately avoids any external dependencies so the toolchain can run
+-- without Zeta installed. All subprocess calls use plain os.execute.
+
+local path = {}
+
+---------------------------------------------------------------------------
+-- String helpers
+---------------------------------------------------------------------------
+
+-- Join path components with a single separator. The first non-empty
+-- component decides whether the result is absolute; later components are
+-- treated as plain name pieces even if they carry a leading slash.
+function path.join(...)
+  local parts = {}
+  local abs = false
+  local first = true
+  for i = 1, select("#", ...) do
+    local part = tostring((select(i, ...)))
+    if part == "/" then
+      if first then abs = true end
+    elseif part ~= "" then
+      local p = part:gsub("^/+", ""):gsub("/+$", "")
+      if p ~= "" then
+        if first then abs = (part:match("^/") ~= nil) end
+        parts[#parts + 1] = p
+      end
+    end
+    first = false
+  end
+  if #parts == 0 then return "/" end
+  local out = table.concat(parts, "/")
+  if abs then out = "/" .. out end
+  return out
+end
+
+function path.is_abs(p)
+  return p:match("^/") ~= nil
+end
+
+function path.basename(p)
+  p = p:gsub("/+$", "")
+  return p:match("[^/]+$") or p
+end
+
+function path.dirname(p)
+  p = p:gsub("/+$", "")
+  if p == "" then return "." end
+  local d = p:match("^(.*)/[^/]+$")
+  if not d then return "." end
+  if d == "" then return "/" end
+  return d
+end
+
+-- Shell-quote a value for safe use in a command. Values containing only
+-- "safe" characters are returned as-is; everything else is single-quoted.
+function path.quote(s)
+  if s == "" then return "''" end
+  if s:match("^[%w%._%/+%-:=@,]+$") then return s end
+  return "'" .. s:gsub("'", "'\\''") .. "'"
+end
+
+---------------------------------------------------------------------------
+-- Filesystem helpers
+---------------------------------------------------------------------------
+
+-- Run a shell command, streaming output to the parent. Returns true on
+-- exit status 0. Compatible with Lua 5.1 through 5.4.
+function path.run(cmd)
+  local a, b, c = os.execute(cmd)
+  if type(a) == "number" then return a == 0 end
+  return a == true and b == "exit" and c == 0
+end
+
+-- mkdir -p wrapper.
+function path.mkdir_p(dir)
+  if dir == "" or dir == "/" then return true end
+  return path.run("mkdir -p " .. path.quote(dir))
+end
+
+-- True if a file or directory (or dangling symlink) exists.
+function path.exists(p)
+  local f = io.open(p, "rb")
+  if f then
+    f:close()
+    return true
+  end
+  return path.run("test -e " .. path.quote(p) .. " -o -L " .. path.quote(p))
+end
+
+-- Package names must be tightly constrained (alphanumeric, dots, underscores,
+-- plus, hyphen). No slashes, no leading dots, no other special characters.
+function path.sanitize_name(name)
+  if type(name) ~= "string" then return nil end
+  if name == "" then return nil end
+  if name:match("^%.") then return nil end
+  if not name:match("^[%w%._+%-]+$") then return nil end
+  return name
+end
+
+---------------------------------------------------------------------------
+-- Download / tool detection
+---------------------------------------------------------------------------
+
+-- True if the given command is available on PATH.
+function path.have(cmd)
+  local f = io.popen("command -v " .. cmd .. " 2>/dev/null")
+  if not f then return false end
+  local out = f:read("*l")
+  f:close()
+  return out ~= nil and out ~= ""
+end
+
+-- Capture stdout of a command. Returns output string or nil on failure.
+function path.capture(cmd)
+  local f = io.popen(cmd .. " 2>/dev/null")
+  if not f then return nil end
+  local out = f:read("*a")
+  f:close()
+  return out
+end
+
+return path