powerline_hg.lua

-- Constants
local segmentColors = {
    branch = {
        fill = colorGreen,
        text = colorBlack
    },
    clean = {
        fill = colorGreen,
        text = colorWhite
    },
    dirty = {
        fill = colorRed,
        text = colorWhite
    }
}

--- copied from clink.lua
 -- Resolves closest directory location for specified directory.
 -- Navigates subsequently up one level and tries to find specified directory
 -- @param  {string} path    Path to directory will be checked. If not provided
 --                          current directory will be used
 -- @param  {string} dirname Directory name to search for
 -- @return {string} Path to specified directory or nil if such dir not found
local function get_dir_contains(path, dirname)

    -- return parent path for specified entry (either file or directory)
    local function pathname(path)
        local prefix = ""
        local i = path:find("[\\/:][^\\/:]*$")
        if i then
            prefix = path:sub(1, i-1)
        end
        return prefix
    end

    -- Navigates up one level
    local function up_one_level(path)
        if path == nil then path = '.' end
        if path == '.' then path = clink.get_cwd() end
        return pathname(path)
    end

    -- Checks if provided directory contains hg directory
    local function has_specified_dir(path, specified_dir)
        if path == nil then path = '.' end
        local found_dirs = clink.find_dirs(path..'/'..specified_dir)
        if #found_dirs > 0 then return true end
        return false
    end

    -- Set default path to current directory
    if path == nil then path = '.' end

    -- If we're already have .hg directory here, then return current path
    if has_specified_dir(path, dirname) then
        return path..'/'..dirname
    else
        -- Otherwise go up one level and make a recursive call
        local parent_path = up_one_level(path)
        if parent_path == path then
            return nil
        else
            return get_dir_contains(parent_path, dirname)
        end
    end
end

-- copied from clink.lua
-- clink.lua is saved under %CMDER_ROOT%\vendor
 function get_hg_dir(path)
    return get_dir_contains(path, '.hg')
end

-- * The segments{} table will hold values for each prompt segment to be (sequentially) displayed
---- * text
---- * textColor: Use one of the color constants. Ex: colorWhite
---- * fillColor: Use one of the color constants. Ex: colorBlue

local segments = {}

---
-- Sets the properties of the Segment object, and prepares for a segment to be added
---
local function init()
    segments = {}

    if get_hg_dir() then
        -- if we're inside of hg repo then try to detect current branch
        -- 'hg id' gives us BOTH the branch name AND an indicator that there
        -- are uncommitted changes, in one fast(er) call
        local pipe = io.popen("hg id 2>&1")
        local output = pipe:read('*all')
        local rc = { pipe:close() }

        if output ~= nil and
           string.sub(output,1,7) ~= "abort: " and             -- not an HG working copy
           string.sub(output,1,12) ~= "000000000000" and       -- empty wc (needs update)
           (not string.find(output, "is not recognized")) then -- 'hg' not in path
            local items = {}
            for i in string.gmatch(output, "%S+") do
                table.insert(items, i)
            end

            -- Branch segment
            table.insert(segments, {" " .. plc_hg_branchSymbol .. " " .. items[2] .. " ", segmentColors.branch.text, segmentColors.branch.fill})

            if string.sub(items[1], -1, -1) == "+" then
                -- Dirty segment
                table.insert(segments, {plc_hg_conflictSymbol,  segmentColors.dirty.text,  segmentColors.dirty.fill})
            end
        end
    end
end 

---
-- Uses the segment properties to add a new segment to the prompt
---
local function addAddonSegment()
    init()
    for i = 1, #segments do
        addSegment(segments[i][1], segments[i][2], segments[i][3])
    end
end 

-- Register this addon with Clink
clink.prompt.register_filter(addAddonSegment, 61)