move helper code into the util module

1 files changed, 164 insertions, 0 deletions

diff --git a/util.lua b/util.lua
new file mode 100644
index 0000000..363549e
--- /dev/null
+++ b/util.lua
@@ -0,0 +1,164 @@
+--- Module containing simple utility functions for vis-lspc/
+-- @module util
+-- @author Florian Fischer
+-- @author git-bruh <prathamIN@proton.me>
+-- @license GPL-3
+-- @copyright 2024 Florian Fischer
+-- @copyright 2024 git-bruh <prathamIN@proton.me>
+local util = {}
+
+local lspc
+
+function util.init(lspc_)
+  lspc = lspc_
+  return util
+end
+
+--- Execute a command and capture its output.
+-- @param cmd the command to execute
+-- @return the output of the command written to stdout
+function util.capture_cmd(cmd)
+  local p = assert(io.popen(cmd, 'r'))
+  local s = assert(p:read('*a'))
+  local success, _, status = p:close()
+  if not success then
+    local err = cmd .. ' failed with exit code: ' .. status
+    lspc:err(err)
+  end
+  return s
+end
+
+local vis_supports_pipe_buf = pcall(vis.pipe, vis, 'foo', 'true')
+
+--- Wrapper for the two vis:pipe variants.
+-- If vis does not support vis:pipe(input, cmd), prefix the command
+-- with a printf call piping the result to the original command.
+-- @param input The input to pipe to the command
+-- @param cmd The external command to pipe the input to
+function util.vis_pipe(input, cmd, fullscreen)
+  if vis_supports_pipe_buf then
+    return vis:pipe(input, cmd, fullscreen or false)
+  end
+
+  local escaped_input = input:gsub('\'', '\'"\'"\'')
+  cmd = 'printf %s \'' .. escaped_input .. '\' | ' .. cmd
+  return vis:pipe(vis.win.file, {start = 0, finish = 0}, cmd)
+end
+
+--- Split a path into its components
+-- @param path the path to split into components
+-- @return a table containing the path components
+function util.split_path_into_components(path)
+  local components = {}
+
+  if #path == 1 then
+    return nil
+  end
+
+  -- Skip the initial '/'
+  local start_idx = 2
+
+  while true do
+    local slash = path:find('/', start_idx + 1)
+
+    if slash == nil then
+      table.insert(components, path:sub(start_idx, #path))
+      return components
+    else
+      table.insert(components, path:sub(start_idx, slash - 1))
+      start_idx = slash + 1
+    end
+  end
+end
+
+--- Get a path relative to the current working directory
+-- @param cwd_components Table of the path components of the CWD
+-- @param absolute_path_or_components absolute path or table of its path components
+-- @return the relative path
+function util.get_relative_path(cwd_components, absolute_path_or_components)
+  local absolute_components
+  if type(absolute_path_or_components) == "string" then
+    absolute_components = util.split_path_into_components(absolute_path_or_components)
+  else
+    absolute_components = absolute_path_or_components
+  end
+
+  for idx = 1, #cwd_components do
+    local cwd = cwd_components[idx]
+    local absolute = absolute_components[idx]
+
+    if cwd ~= absolute then
+      local dir = ''
+
+      -- Atleast the first component must match for us to convert
+      -- it to a relative path
+      if idx ~= 1 then
+        for _ = idx, #cwd_components do
+          dir = dir .. '..' .. '/'
+        end
+
+        -- Skip trailing '/'
+        dir = dir:sub(1, #dir - 1)
+      end
+
+      for i = idx, #absolute_components do
+        dir = dir .. '/' .. absolute_components[i]
+      end
+
+      return dir
+    end
+  end
+
+  -- cwd shorter than absolute path
+  local dir = ''
+
+  for i = #cwd_components + 1, #absolute_components do
+    dir = dir .. '/' .. absolute_components[i]
+  end
+
+  -- Skip leading '/'
+  return dir:sub(2)
+end
+
+--- Create an iterator yielding the nth line of a file
+--
+-- @param path The path to the file
+function util.file_line_iterator_to_n(path)
+  local file = assert(io.open(path, 'r'))
+  local lines = file:lines()
+  local last_line = nil
+  local last_n = 1
+
+  return function(n)
+    if n == -1 then
+      file:close()
+      return nil
+    end
+
+    if n < last_n then
+      -- We might have multiple references on the same line, so we can
+      -- get called again with the previous line number
+      if (n + 1) == last_n then
+        return last_line
+      end
+
+      return nil
+    end
+
+    for line in lines do
+      if n == last_n then
+        last_n = last_n + 1
+        last_line = line
+
+        return line
+      end
+
+      last_n = last_n + 1
+    end
+
+    -- Iterator exhausted
+    return nil
+  end
+end
+
+return util