1  import os, strformat, strutils, rdstdin
 2  
 3  const
 4    gitEnv = "GIT_DIR"
 5    protocol = "crvc"
 6  
 7  proc setup(gitEnv: string, protocol: string): (string, string, string) =
 8    # Checks the Environment and returns the git Working directory, the protocol, the remote and url
 9  
10    if paramCount() < 2:
11      raise newException(ValueError, fmt"Usage: {getAppFilename()} <remote-name> <url>")
12  
13    let
14      remote = paramStr(1) # <remote-name>
15      url = paramStr(2) # <url>
16      gitDir = getEnv(gitEnv)
17  
18    # Check if GIT_DIR Environment Variable is set
19    if gitDir.isNilOrWhitespace:
20      raise newException(OSError, fmt"{gitEnv} is not set")
21  
22    # Check if the .git directory exists
23    if not existsDir(gitDir):
24      raise newException(OSError, fmt"{gitDir} does not appear to be a git repository")
25  
26    # Create our Working Directory if it doesn't exist
27    let path = joinPath(gitDir, remote)
28    if not existsDir(path):
29      createDir(path)
30    # TODO process url and pass to processStdio parseUrl?
31    return (path, remote, url)
32  
33  proc processStdio (env: tuple): void = 
34    # Supports the Git Remote Helper stdio protocol
35    # https://git-scm.com/docs/git-remote-helpers
36    let (path, remote, url) = env
37  
38    while true:
39      var
40        response: string
41        line: string = readLine(stdin) # TODO something better here ? https://nim-lang.org/docs/streams.html
42      # echo line
43  
44      # Git sends the remote helper a list of commands on standard input, one per line. 
45      # The first command is always the capabilities command, in response to which the remote helper must print a list of the capabilities it supports followed by a blank line.
46      case line:
47        of "capabilities":
48          response = "capabilities response"
49        of "list":
50          response = "list response"
51        of "export":
52          response = "export response"
53        else:
54          raise newException(IOError, fmt"Unrecognised command: {line}")
55      write(stdout, response)
56  
57  
58  proc bail() {.noconv.} =
59    quit()
60  
61  when isMainModule:
62    setControlCHook(bail)
63  
64    try:
65      processStdio(setup(gitEnv, protocol))
66    except:
67      echo getCurrentExceptionMsg()
68    finally:
69      quit()