v02gitdiff

#!/usr/bin/env bash

# set a default for the key file if none is given
if [[ -z "${V02ENC_KEY}" ]]
then
  V02ENC_KEY="-"
fi

SCRIPT_DIR="$(/usr/bin/env dirname "$(/usr/bin/env realpath "$0")")"

# handle parameters
GIT_ROOT="${PWD}"
FILE1="${2}"
MODE1="${4}"
FILE2="${5}"
MODE2="${7}"
FILENAME="${1}"

# prepare the output
COMPARED="0"
EXITCODE="0"
OUTPUT=()
TEMPFILE1="${FILE1}"
TEMPFILE2="${FILE2}"

if [[ ${V02ENC_KEY} == "-" || -f "${V02ENC_KEY}" ]]
then
  if [[ -f "${FILE1}" || -f "${FILE2}" ]]
  then
    # check if we are comparing v02enc encrypted files
    if [[ "${FILE1: -7}" == ".v02enc" || "${FILE2: -7}" == ".v02enc" ]]
    then
      # try to read the encryption key
      if [[ -z "${V02ENC_PASSPHRASE}" && "${V02ENC_KEY}" == "-" ]]
      then
        # check if there is a key file
        if [[ -f ~/.v02enc ]]
        then
          # read the key file
          V02ENC_PASSPHRASE="$(/usr/bin/env cat ~/.v02enc | /usr/bin/env xxd -p | /usr/bin/env tr -d "\n")"
        else
          # check if we are running macOS
          OS="$(/usr/bin/env uname -s | /usr/bin/env tr "[:upper:]" "[:lower:]")"

          if [[ "$OS" == "darwin" ]]
          then
            # try to read the default keychain value
            TMP="$(/usr/bin/env security find-generic-password -a "$(/usr/bin/env whoami)" -s "v02enc" -w 2>/dev/null)"

            if [[ "$?" -eq "0" ]]
            then
              V02ENC_PASSPHRASE="${TMP}"
            fi
          fi
        fi
      fi

      # generate the temporary file names
      TEMPFILE1="$(/usr/bin/env mktemp)"
      TEMPFILE2="$(/usr/bin/env mktemp)"

      # prepare exit codes
      EXITCODE1="0"
      EXITCODE2="0"

      if [[ -f "${FILE1}" ]]
      then
        # decrypt the first file
        echo -n "${V02ENC_PASSPHRASE}" | /usr/bin/env xxd -p -r | "${SCRIPT_DIR}/v02enc" --decrypt --key "${V02ENC_KEY}" --input "${FILE1}" --output "${TEMPFILE1}" 2>/dev/null

        # store exit code
        EXITCODE1="$?"

        if [[ "${EXITCODE1}" -eq "0" ]]
        then
          # set restrictive temporary file access
          /usr/bin/env chmod 400 "${TEMPFILE1}"
        fi
      fi

      if [[ -f "${FILE2}" ]]
      then
        # decrypt the second file
        echo -n "${V02ENC_PASSPHRASE}" | /usr/bin/env xxd -p -r | "${SCRIPT_DIR}/v02enc" --decrypt --key "${V02ENC_KEY}" --input "${FILE2}" --output "${TEMPFILE2}" 2>/dev/null

        # store exit code
        EXITCODE2="$?"

        if [[ "${EXITCODE2}" -eq "0" ]]
        then
          # set restrictive temporary file access
          /usr/bin/env chmod 400 "${TEMPFILE2}"
        fi
      fi

      # check that both files could be decrypted
      if [[ "${EXITCODE1}" -eq "0" && "${EXITCODE2}" -eq "0" ]]
      then
        # prevent normal file diff
        COMPARED="1"

        # compare decrypted files
        IFS=$'\n' OUTPUT=($(/usr/bin/env diff --color=always -Npu "${TEMPFILE1}" "${TEMPFILE2}"))

        # store exit code
        EXITCODE="$?"
      fi

      if [[ -f "${FILE1}" ]]
      then
        # try to delete the temporary file either way
        /usr/bin/env rm -f "${TEMPFILE1}"
      fi

      if [[ -f "${FILE2}" ]]
      then
        # try to delete the temporary file either way
        /usr/bin/env rm -f "${TEMPFILE2}"
      fi
    fi
  fi
fi

# handle as normal files
if [[ "${COMPARED}" -eq "0" ]]
then
  # reset temporary file names
  TEMPFILE1="${FILE1}"
  TEMPFILE2="${FILE2}"

  # just to be sure
  COMPARED="1"

  # compare decrypted files
  IFS=$'\n' OUTPUT=($(/usr/bin/env diff --color=always -Npu "${TEMPFILE1}" "${TEMPFILE2}"))

  # store exit code
  EXITCODE="$?"
fi

# only handle output if there is any output
if [[ "${#OUTPUT[@]}" -gt "0" ]]
then
  if [[ "${MODE1}" != "${MODE2}" ]]
  then
    echo "old mode ${MODE1}"
    echo "new mode ${MODE2}"
  fi

  # check for the known exit code
  if [[ "${EXITCODE}" -eq "1" ]]
  then
    # check if the output is a diff
    if [[ "${OUTPUT[0]:0:3}" == "---" ]]
    then
      # prepare first output line
      if [[ "${FILE1}" == "/dev/null" ]]
      then
        OUTPUT[0]="--- /dev/null"
      else
        OUTPUT[0]="--- a/${FILENAME}"
      fi

      # prepare second output line
      if [[ "${FILE2}" == "/dev/null" || ! -f "${FILE2}" ]]
      then
        OUTPUT[1]="+++ /dev/null"
      else
        OUTPUT[1]="+++ b/${FILENAME}"
      fi

      printf "%s\n" "${OUTPUT[@]}" | /usr/bin/env colordiff
    else
      # prepare placeholders
      PLACEHOLDER1=""
      PLACEHOLDER2=""

      if [[ "${FILE1}" == "/dev/null" ]]
      then
        PLACEHOLDER1="/dev/null"
      else
        PLACEHOLDER1="a/${FILENAME}"
      fi

      if [[ "${FILE2}" == "/dev/null" || ! -f "${FILE2}" ]]
      then
        PLACEHOLDER2="/dev/null"
      else
        PLACEHOLDER2="b/${FILENAME}"
      fi

      echo -e "Binary files ${PLACEHOLDER1} and ${PLACEHOLDER2} differ\n" | /usr/bin/env colordiff
    fi
  else
    # just output the text
    printf "%s\n" "${OUTPUT[@]}"
  fi
fi