# Copyright 2018 The Bazel Authors. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Runfiles lookup library for Bazel-built Bash binaries and tests.
#
# ENVIRONMENT:
# - Use the example code provided below. It initializes the environment
#   variables required by this script.
# - If RUNFILES_LIB_DEBUG=1 is set, the script will print diagnostic messages to
#   stderr.
#
# USAGE:
# 1.  Depend on this runfiles library from your build rule:
#
#       sh_binary(
#           name = "my_binary",
#           ...
#           deps = ["@bazel_tools//tools/bash/runfiles"],
#       )
#
# 2.  Source the runfiles library.
#
#     The runfiles library itself defines rlocation which you would need to look
#     up the library's runtime location, thus we have a chicken-and-egg problem.
#     Insert the following code snippet to the top of your main script:
#
#       # --- begin runfiles.bash initialization ---
#       set -euo pipefail
#       if [[ ! -d "${RUNFILES_DIR:-/dev/null}" && ! -f "${RUNFILES_MANIFEST_FILE:-/dev/null}" ]]; then
#         if [[ -f "$0.runfiles_manifest" ]]; then
#           export RUNFILES_MANIFEST_FILE="$0.runfiles_manifest"
#         elif [[ -f "$0.runfiles/MANIFEST" ]]; then
#           export RUNFILES_MANIFEST_FILE="$0.runfiles/MANIFEST"
#         elif [[ -f "$0.runfiles/bazel_tools/tools/bash/runfiles/runfiles.bash" ]]; then
#           export RUNFILES_DIR="$0.runfiles"
#         fi
#       fi
#       if [[ -f "${RUNFILES_DIR:-/dev/null}/bazel_tools/tools/bash/runfiles/runfiles.bash" ]]; then
#         source "${RUNFILES_DIR}/bazel_tools/tools/bash/runfiles/runfiles.bash"
#       elif [[ -f "${RUNFILES_MANIFEST_FILE:-/dev/null}" ]]; then
#         source "$(grep -m1 "^bazel_tools/tools/bash/runfiles/runfiles.bash " \
#                   "$RUNFILES_MANIFEST_FILE" | cut -d ' ' -f 2-)"
#       else
#         echo >&2 "ERROR: cannot find @bazel_tools//tools/bash/runfiles:runfiles.bash"
#         exit 1
#       fi
#       # --- end runfiles.bash initialization ---
#
# 3.  Use rlocation to look up runfile paths:
#
#       cat "$(rlocation my_workspace/path/to/my/data.txt)"
#

case "$(uname -s | tr [:upper:] [:lower:])" in
msys*|mingw*|cygwin*)
  # matches an absolute Windows path
  export _RLOCATION_ISABS_PATTERN="^[a-zA-Z]:[/\\]"
  ;;
*)
  # matches an absolute Unix path
  export _RLOCATION_ISABS_PATTERN="^/[^/].*"
  ;;
esac

# Prints to stdout the runtime location of a data-dependency.
function rlocation() {
  if [[ "${RUNFILES_LIB_DEBUG:-}" == 1 ]]; then
    echo >&2 "INFO[runfiles.bash]: rlocation($1): start"
  fi
  if [[ "$1" =~ $_RLOCATION_ISABS_PATTERN ]]; then
    if [[ "${RUNFILES_LIB_DEBUG:-}" == 1 ]]; then
      echo >&2 "INFO[runfiles.bash]: rlocation($1): absolute path, return"
    fi
    # If the path is absolute, print it as-is.
    echo $1
  elif [[ "$1" == ../* || "$1" == */.. || "$1" == ./* || "$1" == */./* || "$1" == "*/." || "$1" == *//* ]]; then
    if [[ "${RUNFILES_LIB_DEBUG:-}" == 1 ]]; then
      echo >&2 "ERROR[runfiles.bash]: rlocation($1): path is not normalized"
    fi
    return 1
  elif [[ "$1" == \\* ]]; then
    if [[ "${RUNFILES_LIB_DEBUG:-}" == 1 ]]; then
      echo >&2 "ERROR[runfiles.bash]: rlocation($1): absolute path without" \
               "drive name"
    fi
    return 1
  else
    if [[ -f "${RUNFILES_DIR:-/dev/null}/$1" ]]; then
      if [[ "${RUNFILES_LIB_DEBUG:-}" == 1 ]]; then
        echo >&2 "INFO[runfiles.bash]: rlocation($1): found under RUNFILES_DIR ($RUNFILES_DIR), return"
      fi
      echo "${RUNFILES_DIR}/$1"
    elif [[ -f "${RUNFILES_MANIFEST_FILE:-/dev/null}" ]]; then
      if [[ "${RUNFILES_LIB_DEBUG:-}" == 1 ]]; then
        echo >&2 "INFO[runfiles.bash]: rlocation($1): looking in RUNFILES_MANIFEST_FILE ($RUNFILES_MANIFEST_FILE)"
      fi
      local -r result=$(grep -m1 "^$1 " "${RUNFILES_MANIFEST_FILE}" | cut -d ' ' -f 2-)
      if [[ -f "${result:-/dev/null}" ]]; then
        if [[ "${RUNFILES_LIB_DEBUG:-}" == 1 ]]; then
          echo >&2 "INFO[runfiles.bash]: rlocation($1): found in manifest as ($result)"
        fi
        echo "$result"
      else
        if [[ "${RUNFILES_LIB_DEBUG:-}" == 1 ]]; then
          echo >&2 "INFO[runfiles.bash]: rlocation($1): not found in manifest"
        fi
        echo ""
      fi
    else
      if [[ "${RUNFILES_LIB_DEBUG:-}" == 1 ]]; then
        echo >&2 "ERROR[runfiles.bash]: cannot look up runfile \"$1\" " \
                 "(RUNFILES_DIR=\"${RUNFILES_DIR:-}\"," \
                 "RUNFILES_MANIFEST_FILE=\"${RUNFILES_MANIFEST_FILE:-}\")"
      fi
      return 1
    fi
  fi
}
export -f rlocation

# Exports the environment variables that subprocesses need in order to use
# runfiles.
# If a subprocess is a Bazel-built binary rule that also uses the runfiles
# libraries under @bazel_tools//tools/<lang>/runfiles, then that binary needs
# these envvars in order to initialize its own runfiles library.
function runfiles_export_envvars() {
  if [[ ! -f "${RUNFILES_MANIFEST_FILE:-/dev/null}" \
        && ! -d "${RUNFILES_DIR:-/dev/null}" ]]; then
    return 1
  fi

  if [[ ! -f "${RUNFILES_MANIFEST_FILE:-/dev/null}" ]]; then
    if [[ -f "$RUNFILES_DIR/MANIFEST" ]]; then
      export RUNFILES_MANIFEST_FILE="$RUNFILES_DIR/MANIFEST"
    elif [[ -f "${RUNFILES_DIR}_manifest" ]]; then
      export RUNFILES_MANIFEST_FILE="${RUNFILES_DIR}_manifest"
    else
      export RUNFILES_MANIFEST_FILE=
    fi
  elif [[ ! -d "${RUNFILES_DIR:-/dev/null}" ]]; then
    if [[ "$RUNFILES_MANIFEST_FILE" == */MANIFEST \
          && -d "${RUNFILES_MANIFEST_FILE%/MANIFEST}" ]]; then
      export RUNFILES_DIR="${RUNFILES_MANIFEST_FILE%/MANIFEST}"
      export JAVA_RUNFILES="$RUNFILES_DIR"
    elif [[ "$RUNFILES_MANIFEST_FILE" == *_manifest \
          && -d "${RUNFILES_MANIFEST_FILE%_manifest}" ]]; then
      export RUNFILES_DIR="${RUNFILES_MANIFEST_FILE%_manifest}"
      export JAVA_RUNFILES="$RUNFILES_DIR"
    else
      export RUNFILES_DIR=
    fi
  fi
}
export -f runfiles_export_envvars