Göran Krampe / Blimp

import md5, os, osproc, parseopt2, strutils, parsecfg, streams, lapp, tables, sets

# blimp is a little utility program for handling large files
# in git repositories. Its inspired by git-fat and s3annex
# but doesn't rely on S3 for storage - it uses scp but
# performs the file operations using externally configured commands.
# It is a single binary without any dependencies.
#
# It can also keep track of multiple remote areas and do up/downloads
# independent from git. This is useful in build scripts, up and
# downloading artifacts.
#
# Just run blimp --help for detailed help.

const
  versionMajor* = 0
  versionMinor* = 6
  versionPatch* = 0
  versionAsString* = $versionMajor & "." & $versionMinor & "." & $versionPatch

type
  RemoteArea = ref object of RootObj
    name*: string
    url*: string
    upload*: string
    download*: string
    delete*: string

var
  blimpStore, blimpVersion: string = nil
  homeDir, currentDir, gitRootDir: string
  verbose, stdio, onAllDeflated, onAllFiltered: bool
  stdinContent, area: string = nil
  areas = newTable[string, RemoteArea]()
  remoteArea: RemoteArea

let defaultConfig = """
[blimp]
# Minimal version, otherwise stop
version = """ & versionAsString & """
#
# Set your local blimpstore directory. You can use %home%,
# %cwd% and %gitroot% in paths, works cross platform.
#
# Example:
#   # Place it inside the git clone
#   blimpstore = "%gitroot%/.git/blimpstore"
#
#   # Place it in current working directory (not very useful)
#   blimpstore = "%cwd%/blimpstore"
#
# Default:
#   # Place it in the users home directory
blimpstore = "%home%/blimpstore"


[remote]
# The "remote" area represents the shared remote blimpstore.
# This area is the default area used unless --area is used.
url = "blimp@build.3dicc.com:/var/opt/blimpstore"

# On Windows we rely on msysgit that includes scp.
# On XP, make sure to put your ssh keys
# in c:\Program Files\git\.ssh (slightly odd place)
# On Win7 it uses c:\Users\gokr\.ssh - you can check with
# "ssh -v somehost" to see where it looks for the keys.
#
# When expanding the command templates below:
#   $1 is the blimp filename
#   $2 is the area url above
#   $3 is the local blimpstore directory
upload = "scp -pqC '$3/$1' '$2/'"
download = "scp -pqC '$2/$1' '$3/'"


[release]
# This area can be used with upload/download commands and --area option.
# -r makes it possible to give directories as arguments for recursive handling.
url = "blimp@build.3dicc.com:/var/opt/release"
upload = "scp -rC '$3/$1' '$2/'"
download = "scp -rC '$2/$1' '$3/'"
"""


proc cmd(cmd: string): string =
  try:
    # Otherwise pipes will not work for git commands etc
    when defined(windows):
      let tup = execCmdEx("cmd /c \"" & cmd & "\"")
    else:
      let tup = execCmdEx(cmd)
    #echo "cmd: " & $cmd & "err:" & $tup[1]
    if tup[1] == 0:
      result = strip(tup[0])
    else:
      result = nil
  except:
    result = nil

# Various git commands
proc gitRoot(): string =
  cmd("git rev-parse --show-toplevel")
proc gitConfigSet(key, val: string) =
  discard cmd("git config " & $key & " " & $val)
proc gitConfigUnset(key: string) =
  discard cmd("git config --unset " & $key)
proc gitConfigGet(key: string): string =
  cmd("git config --get " & $key)

# Ensure the filter is set
proc ensureBlimpFilter() =
  if gitConfigGet("filter.blimp.clean") != "":
    gitConfigSet("filter.blimp.clean", "\"blimp -s d %f\"")
    gitConfigSet("filter.blimp.smudge", "\"blimp -s i %f\"")

# Ensure the filter is set
proc removeBlimpFilter() =
  if gitConfigGet("filter.blimp.clean") != "":
    gitConfigUnset("filter.blimp.clean")
    gitConfigUnset("filter.blimp.smudge")

# Simple expansion of %home%, %cwd% and %gitroot%
proc expandDirs(templ: string): string =
  result = templ.replace("%home%", homeDir)
  result = result.replace("%cwd%", currentDir)
  if result.contains("%gitroot%"):
    if gitRootDir.isNil: quit("Not in a git clone, can not expand %gitroot% in '" & templ & "'")
    result = result.replace("%gitroot%", gitRootDir)

# Copy of readAllBuffer from sysio.nim - we need to call it
# instead of readAll(stdin) which doesn't work on Windows. readAll
# first tries to find file size, and that trips up Windows.
proc readAllX(file: File): string =
  result = ""
  var buffer = newString(4096)
  while true:
    var read = readBuffer(file, addr(buffer[0]), 4096)
    if read == 4096:
      result.add(buffer)
    else:
      buffer.setLen(read)
      result.add(buffer)
      break

# Load a blimp.conf file
proc parseConfFile(filename: string) =
  var f = newFileStream(filename, fmRead)
  if f != nil:
    if verbose: echo "Reading config: " & filename
    var p: CfgParser
    open(p, f, filename)
    var section: string
    var area: RemoteArea
    while true:
      var e = next(p)
      case e.kind
      of cfgEof:
        break
      of cfgSectionStart:
        section = e.section
      of cfgKeyValuePair:
        case section
        of "blimp":
          case e.key
          of "blimpstore":
            if blimpStore.isNil: blimpStore = expandDirs(e.value)
          of "version":
            if blimpVersion.isNil: blimpVersion = e.value
          else:
            quit("Unknown blimp configuration: " & e.key)
        else:
          # Then we presume its an area
          if area.isNil or area.name != section:
            area = RemoteArea(name: section)
            areas[area.name] = area
          case e.key
          of "url":
            if area.url.isNil: area.url = expandDirs(e.value)
          of "upload":
            if area.upload.isNil: area.upload = expandDirs(e.value)
          of "download":
            if area.download.isNil: area.download = expandDirs(e.value)
          of "delete":
            if area.delete.isNil: area.delete = expandDirs(e.value)
          else:
            quit("Unknown area configuration: " & e.key)
      of cfgOption:
        quit("Unknown configuration: " & e.key)
      of cfgError:
        quit("Parsing " & filename & ": " & e.msg)
    close(p)

# Trivial helper to enable verbose
proc run(cmd: string): int =
  if verbose: echo(cmd)
  execCmd(cmd)

# Perhaps not perfect but tries to convert c:\foo\bar to /c/foo/bar
# but only if we are on windows, otherwise we do nothing.
proc toUnixyPath(path: string): string =
  when defined(windows):
    if path.len > 1 and path[1] == ':':
      let parts = path.split({':', '\\'})
      result = "/" & parts.join("/")
    else:
      result = path
  else:
    result = path

# Upload a file to the remote area
proc uploadFile(filename, fromDir: string) =
  if remoteArea.isNil:
    echo("Remote area not set in configuration file, skipping uploading content:\n\t" & filename)
    return
  let errorCode = run(format(remoteArea.upload, filename, remoteArea.url, toUnixyPath(fromDir)))
  if errorCode != 0:
    quit("Something went wrong uploading " & filename & " to " & remoteArea.url, 2)

# Download a file to the remote area
proc downloadFile(filename, toDir: string) =
  if remoteArea.isNil:
    quit("Remote area not set in configuration file, can not download content:\n\t" & filename)
  let errorCode = run(format(remoteArea.download, filename, remoteArea.url, toUnixyPath(toDir)))
  if errorCode != 0:
    quit("Something went wrong downloading " & filename & " from " & remoteArea.url, 3)

# Delete a file from the remote master blimpStore
proc remoteDeleteFile(filename: string) =
  if remoteArea.isNil:
    return
  let errorCode = run(format(remoteArea.delete, filename, remoteArea.url, toUnixyPath(blimpStore)))
  if errorCode != 0:
    quit("Something went wrong deleting " & filename & " from " & remoteArea.url, 3)

# Copy content to blimpStore and upload if it was a new file or upload == true.
proc copyToBlimpStore(filename, blimpFilename: string) =
  if not existsFile(blimpStore / blimpFilename):
    if stdio:
      try:
        writeFile(blimpStore / blimpFilename, stdinContent)
      except:
        quit("Failed writing file: " & blimpStore / blimpFilename & " from stdin", 1)
    else:
      copyFile(filename, blimpStore / blimpFilename)
    uploadFile(blimpFilename, blimpStore)


# Copy content from blimpStore, and downloading first if needed
proc copyFromBlimpStore(blimpFilename, filename: string) =
  if not existsFile(blimpStore / blimpFilename):
    downloadFile(blimpFilename, blimpStore)
  if stdio:
    try:
      var content = readFile(blimpStore / blimpFilename)
      write(stdout, content)
    except:
      quit("Failed reading file: " & blimpStore / blimpFilename & " to stdout", 1)
  else:
    copyFile(blimpStore / blimpFilename, filename)

# Delete from blimpStore and remote.
proc deleteFromBlimpStore(blimpFilename, filename: string) =
  if existsFile(blimpStore / blimpFilename):
    removeFile(blimpStore / blimpFilename)
  remoteDeleteFile(blimpFilename)

proc blimpFileNameFromString(line: string): string =
  let hashline = split(strip(line), ':')
  if hashline[0] == "blimphash":
    result = hashline[1]
  else:
    result = nil

# Pick out blimpFilename (filename & "-" & hash) or nil
proc blimpFileName(filename: string): string =
  if stdio:
    blimpFileNameFromString(stdinContent)
  else:
    var hashfile: File
    if not open(hashfile, filename):
      quit("Failed opening file: " & filename, 4)
    blimpFileNameFromString(string(readLine(hashfile)))

# Get hash and compute blimpFilename
proc computeBlimpFilename(filename: string): string =
  var content: string
  try:
    content = readFile(filename)
  except:
    quit("Failed opening file: " & filename, 1)
  let hash = getMD5(content)
  result = extractFilename(filename) & "-" & hash

# Copy original file to blimpStore and replace with hash stub in git.
proc deflate(filename: string) =
  if verbose: echo "Deflating " & filename
  var blimpFilename = blimpFilename(filename)
  if not blimpFilename.isNil:
    echo("\t" & filename & " is already deflated, skipping.")
  else:
    blimpFilename = computeBlimpFilename(filename)
    copyToBlimpStore(filename, blimpFilename)
    if stdio:
      write(stdout, "blimphash:" & blimpFilename)
    else:
      writeFile(filename, "blimphash:" & blimpFilename)
    if verbose: echo("\t" & filename & " deflated.")

# Iterator over all deflated files in the git clone
iterator allDeflated(): string =
  let filenames = cmd("git ls-files " & gitRootDir).split({'\l', '\c'})
  for fn in filenames:
    if not blimpFilename(fn).isNil:
      yield fn

# Iterator over all files matching the blimp filter in the git clone
iterator allFiltered(): string =
  let lines = cmd("git ls-files | git check-attr --stdin filter").split({'\l', '\c'})
  for line in lines:
    let status = line.split(':')
    if strip(status[2]) == "blimp":
      yield status[0]

# Parse out hash from hash stub and copy back original content from blimpStore.
proc inflate(filename: string) =
  if verbose: echo "Inflating " & filename
  let blimpFilename = blimpFilename(filename)
  if blimpFilename.isNil:
    echo("\t" & filename & " is not deflated, skipping.")
  else:
    copyFromBlimpStore(blimpfilename, filename)
    if verbose: echo("\t" & filename & " inflated.")

# Inflates file first (if deflated) and then removes current content for it,
# both locally and in remote.
proc remove(filename: string) =
  var blimpFilename = blimpFilename(filename)
  if not blimpFilename.isNil:
    copyFromBlimpStore(blimpfilename, filename)
  else:
    blimpFilename = computeBlimpFilename(filename)
  deleteFromBlimpStore(blimpfilename, filename)
  echo("\t" & filename & " content removed from blimpstore locally and remotely.")


# Make sure a file already in blimpstore is uploaded to remote area.
proc push(filename: string) =
  if verbose: echo "Uploading " & filename
  var blimpFilename = blimpFilename(filename)
  if blimpFilename.isNil:
    blimpFilename = computeBlimpFilename(filename)
  if existsFile(blimpStore / blimpFilename):
    uploadFile(blimpFilename, blimpStore)
    if verbose: echo("\t" & filename & " uploaded.")
  else:
    if verbose: echo("\t" & filename & " is not in blimpstore, skipping.")

# Upload a file to a remote area
proc upload(filename: string) =
  if verbose: echo "Uploading " & filename
  uploadFile(filename, currentDir)
  if verbose: echo("\t" & filename & " uploaded.")

# Download a file from a remote area.
proc download(filename: string) =
  if verbose: echo "Downloading " & filename
  downloadFile(filename, currentDir)
  if verbose: echo("\t" & filename & " downloaded.")

proc setupBlimpStore() =
  try:
    if not existsDir(blimpStore):
      createDir(blimpStore)
  except:
    quit("Could not create " & blimpStore & " directory.", 1)

  try:
    if not existsFile(blimpStore / ".blimp.conf"):
      writeFile(blimpStore / ".blimp.conf", defaultConfig)
  except:
    quit("Could not create .blimp.conf config file in " & blimpStore & " directory.", 1)

proc `$`(x: string): string =
  if x.isNil: "nil" else: x

proc dumpConfig() =
  echo "\nDump of configuration:"
  echo "\tblimpStore: " & blimpStore
  echo "\tremote-url: " & remoteArea.url
  echo "\tremote-upload: " & remoteArea.upload
  echo "\tremote-download: " & remoteArea.download
  echo "\tblimpVersion: " & $blimpVersion
  echo "\n"

let synopsis = """
  blimp [options] <command> <filenames...>
    -h,--help                  Show this
    --version                  Show version of blimp
    -v,--verbose               Verbosity, only works without -s
    ----------
    <command>  (string)        (d)eflate, (i)nflate, init, deinit,
                               remove, push, upload, download
    --all                      Operate on all deflated files in clone
    -f,--filter                Operate on all files matching blimp filter
    -a,--area (default remote) The area to use for remote up/downloads
    ----------
    -s,--stdio                 If given, use stdin/stdout for content.
    <filenames> (string...)    One or more filepaths to inflate/deflate"""
let help = """

  blimp is a little utility program for handling large files
  in git repositories. Its inspired by git-fat and s3annex
  but doesn't rely on S3 for storage - it uses rsync like git-fat.
  It is a single binary without any dependencies. Its not as advanced
  as git-fat but basically does the same thing.

  Manual use:

  Use "blimp d mybigfile" to deflate a file, typically before commit.
  Use "blimp i mybigfile" to inflate it back to original content.

  When deflated the file only has this content:

    "blimphash:" <filename> "-" <md5sum>

  Deflate also copies the real content to your local blimpstore:

    <blimpstore>/<filename>-<md5sum>

  ...and if configured also uploads it to "remote", using rsync.

  Configuration is in these locations in order:

    ./.blimp.conf
    <gitroot>/.blimp.conf
    ~/<blimpstore>/.blimp.conf
    ~/.blimp.conf

  This way you can have settings per directory, per git clone,
  per store and per user. A default blimpstore with a commented .blimp.conf
  is created in ~/blimpstore if you run blimp and no .blimp.conf is found.

  Edit ~/blimpstore/.blimp.conf (or in another location) and set a proper
  remote and the proper rsync password. This ensures that its also properly
  synced with a master rsync repository that is typically shared.

  Inflate will bring back the original content by copying from
  your local blimpstore, and if its not there, first download from the remote.
  Use this whenever you need to work/edit the big file - in order to get
  its real content.

  The filenames given are all processed. If -s is used content is processed via
  stdin/stdout and only one filename can be passed. This is used when running blimp
  via a git filter (smudge/clean), see below.

  The remove command (no single character shortcut) will remove the file(s) content
  both from the local blimpstore and from the remote. This only removes
  the current content version, not older versions. The file itself is first
  inflated, if needed, and not deleted. This only "unblimps" the file.

  The push command (no single character shortcut) will force upload the given file
  from the local blimpstore to the remote. This is normally done automatically,
  but this way you can make sure they are synced onto the remote.

  The upload and download commands are used to distribute artifacts typically in a
  build script. If no --area is given, they use the standard "remote" area.

  In order to have blimp work automatically you can:

  * Create a .gitattributes file with lines like:
    *.png filter=blimp binary

  * Configure blimp as a filter by running:
    git config filter.blimp.clean "blimp -s d %f"
    git config filter.blimp.smudge "blimp -s i %f"

  The above git config can be done by running "blimp init" just like git.

  When the above is done (per clone) git will automatically run blimp deflate
  just before committing and blimp inflate when operations are done.

  This means that if you clone a git repository that already has a .gitattributes
  file in it that uses the blimp filter, then you should do:

    blimp init
    blimp inflate --filter

  This will configure the blimp filter and then find and inflate all deflated
  files throughout the clone.
"""

################################ main #####################################
# Set some dirs
homeDir = getHomeDir()
homeDir = homeDir[0..^2] # Not sure why it keeps a trailing "/" on Linux
currentDir = getCurrentDir()
gitRootDir = gitRoot()

# Using lapp to get args, on parsing failure this will show usage automatically
var args = parse(synopsis)
verbose = args["verbose"].asBool
stdio = args["stdio"].asBool
onAllDeflated = args["all"].asBool
onAllFiltered = args["filter"].asBool
area = args["area"].asString

# Can't do verbose with -s, that messes up stdout,
# read in all of stdin once and for all
if stdio:
  verbose = false
  try:
    stdinContent = readAllX(stdin)
    close(stdin)
  except:
    quit("Failed reading stdin", 1)

# Parse configuration files, may shadow and override each other
parseConfFile(currentDir / ".blimp.conf")
if not gitRootDir.isNil and gitRootDir != currentDir:
  parseConfFile(gitRootDir / ".blimp.conf")

if existsDir(homeDir / "blimpstore"):
  parseConfFile(homeDir / "blimpstore" / ".blimp.conf")

parseConfFile(homeDir / ".blimp.conf")

# If we haven't gotten a blimpstore yet, we set a default one
if blimpStore.isNil:
  blimpStore = homeDir / "blimpstore"

# Check if we have a configured remoteArea
if areas.hasKey(area):
  remoteArea = areas[area]

# Let's just show what we have :)
if verbose: dumpConfig()

# These two are special, they short out
if args.showHelp: quit(synopsis & help)
if args.showVersion: quit("blimp version: " & versionAsString)

# Check blimpVersion
if not blimpVersion.isNil and blimpVersion != versionAsString:
  quit("Wrong version of blimp, configuration wants: " & blimpVersion)


# Ok, let's see
var filenames = initSet[string]()

# Add upp all files to operate on in a Set
if args.hasKey("filenames"):
  for f in args["filenames"].asSeq:
    if f.asString != "":
      filenames.incl(f.asString)
if onAllDeflated:
  for fn in allDeflated():
    filenames.incl(fn)
if onAllFiltered:
  for fn in allFiltered():
    filenames.incl(fn)

# Make sure the local blimpstore is setup.
setupBlimpStore()


# Do the deed
let command = args["command"].asString
if command != "":
  # Should we install the filter?
  if command == "init":
    ensureBlimpFilter()
    echo("Installed blimp filter")
    quit(0)
  elif command == "deinit":
    removeBlimpFilter()
    echo("Removed blimp filter")
    quit(0)
  elif command == "d" or command == "deflate":
    for fn in filenames:
      deflate(fn)
  elif command == "i" or command == "inflate":
    for fn in filenames:
      inflate(fn)
  elif command == "remove":
    for fn in filenames:
      remove(fn)
  elif command == "push":
    for fn in filenames.items:
      push(fn)
  elif command == "upload":
    for fn in filenames.items:
      upload(fn)
  elif command == "download":
    for fn in filenames.items:
      download(fn)
  else:
    quit("Unknown command: \"" & command & "\", use --help for valid commands.", 6)

# All good
quit(0)