# 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, version 2.
#
# VERSION HISTORY:
# - version 2: Shorter init code.
#   Features:
#     - "set -euo pipefail" only at end of init code.
#       "set -e" breaks the source <path1> || source <path2> || ... scheme on
#       macOS, because it terminates if path1 does not exist.
#     - Not exporting any environment variables in init code.
#       This is now done in runfiles.bash itself.
#   Compatibility:
#     - The v1 init code can load the v2 library, i.e. if you have older source
#       code (still using v1 init) then you can build it with newer Bazel (which
#       contains the v2 library).
#     - The reverse is not true: the v2 init code CANNOT load the v1 library,
#       i.e. if your project (or any of its external dependencies) use v2 init
#       code, then you need a newer Bazel version (which contains the v2
#       library).
# - version 1: Original Bash runfiles library.
#
# ENVIRONMENT:
# - 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 v2 ---
#       # Copy-pasted from the Bazel Bash runfiles library v2.
#       set -uo pipefail; f=bazel_tools/tools/bash/runfiles/runfiles.bash
#       source "${RUNFILES_DIR:-/dev/null}/$f" 2>/dev/null || \
#         source "$(grep -sm1 "^$f " "${RUNFILES_MANIFEST_FILE:-/dev/null}" | cut -f2- -d' ')" 2>/dev/null || \
#         source "$0.runfiles/$f" 2>/dev/null || \
#         source "$(grep -sm1 "^$f " "$0.runfiles_manifest" | cut -f2- -d' ')" 2>/dev/null || \
#         source "$(grep -sm1 "^$f " "$0.exe.runfiles_manifest" | cut -f2- -d' ')" 2>/dev/null || \
#         { echo>&2 "ERROR: cannot find $f"; exit 1; }; f=; set -e
#       # --- end runfiles.bash initialization v2 ---
#
#
# 3.  Use rlocation to look up runfile paths.
#
#       cat "$(rlocation my_workspace/path/to/my/data.txt)"
#

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

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($1): absolute path without" \
               "drive name"
    fi
    return 1
  else
    if [[ -e "${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 [[ -z "$result" ]]; then
        # If path references a runfile that lies under a directory that itself
        # is a runfile, then only the directory is listed in the manifest. Look
        # up all prefixes of path in the manifest and append the relative path
        # from the prefix if there is a match.
        local prefix="$1"
        local prefix_result=
        local new_prefix=
        while true; do
          new_prefix="${prefix%/*}"
          [[ "$new_prefix" == "$prefix" ]] && break
          prefix="$new_prefix"
          prefix_result=$(grep -m1 "^$prefix " "${RUNFILES_MANIFEST_FILE}" | cut -d ' ' -f 2-)
          [[ -z "$prefix_result" ]] && continue
          local -r candidate="${prefix_result}${1#"${prefix}"}"
          if [[ -e "$candidate" ]]; then
            if [[ "${RUNFILES_LIB_DEBUG:-}" == 1 ]]; then
              echo >&2 "INFO[runfiles.bash]: rlocation($1): found in manifest as ($candidate) via prefix ($prefix)"
            fi
            echo "$candidate"
            return 0
          fi
          # At this point, the manifest lookup of prefix has been successful,
          # but the file at the relative path given by the suffix does not
          # exist. We do not continue the lookup with a shorter prefix for two
          # reasons:
          # 1. Manifests generated by Bazel never contain a path that is a
          #    prefix of another path.
          # 2. Runfiles libraries for other languages do not check for file
          #    existence and would have returned the non-existent path. It seems
          #    better to return no path rather than a potentially different,
          #    non-empty path.
          break
        done
        if [[ "${RUNFILES_LIB_DEBUG:-}" == 1 ]]; then
          echo >&2 "INFO[runfiles.bash]: rlocation($1): not found in manifest"
        fi
        echo ""
      else
        if [[ -e "$result" ]]; then
          if [[ "${RUNFILES_LIB_DEBUG:-}" == 1 ]]; then
            echo >&2 "INFO[runfiles.bash]: rlocation($1): found in manifest as ($result)"
          fi
          echo "$result"
        fi
      fi
    else
      if [[ "${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