Add cog setup scripts

This script has the following functionality:
1. Sets up the `out` symlink to point to a default location on disk
2. Copies RBE binaries outside Cog (temporary fix for build stall problem) - b/289391270
3. Exports ANDROID_BUILD_ENVIRONMENT_CONFIG variable to point to googler-cog.json file. This file will be available in aosp-main-with-phones and goog/main and downstream branches.

TESTED=ran the script within and outside the Cog workspace to test it.

Bug: b/295053716
Change-Id: I59cd6d2d5f954be6f7e4ecd7d64de1e63e51b72e

cogsetup.sh

@@ -0,0 +1,89 @@
+#
+# Copyright (C) 2023 The Android Open Source Project
+#
+# 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.
+#
+
+# This file is executed by build/envsetup.sh, and can use anything
+# defined in envsetup.sh.
+function _create_out_symlink_for_cog() {
+  if [[ "${OUT_DIR}" == "" ]]; then
+    OUT_DIR="out"
+  fi
+
+  if [[ -L "${OUT_DIR}" ]]; then
+    return
+  fi
+  if [ -d "${OUT_DIR}" ]; then
+    echo -e "\tOutput directory ${OUT_DIR} cannot be present in a Cog workspace."
+    echo -e "\tDelete \"${OUT_DIR}\" or create a symlink from \"${OUT_DIR}\" to a directory outside your workspace."
+    return 1
+  fi
+
+  DEFAULT_OUTPUT_DIR="${HOME}/.cog/android-build-out"
+  mkdir -p ${DEFAULT_OUTPUT_DIR}
+  ln -s ${DEFAULT_OUTPUT_DIR} `pwd`/out
+}
+
+# This function moves the reclient binaries into a directory that exists in a
+# non-cog part of the overall filesystem.  This is to workaround the problem
+# described in b/289391270.
+function _copy_reclient_binaries_from_cog() {
+  local NONCOG_RECLIENT_BIN_DIR="${HOME}/.cog/reclient/bin"
+  if [ ! -d "$NONCOG_RECLIENT_BIN_DIR" ]; then
+    # Create the non cog directory if it doesn't exist.
+    mkdir -p ${NONCOG_RECLIENT_BIN_DIR}
+  else
+    # Clear out the non cog directory if it does exist.
+    rm -f ${NONCOG_RECLIENT_BIN_DIR}/*
+  fi
+
+  local TOP=$(gettop)
+
+  # Copy the binaries out of live.
+  cp $TOP/prebuilts/remoteexecution-client/live/* $NONCOG_RECLIENT_BIN_DIR
+
+  # Finally set the RBE_DIR env var to point to the out-of-cog directory.
+  export RBE_DIR=$NONCOG_RECLIENT_BIN_DIR
+}
+
+# This function sets up the build environment to be appropriate for Cog.
+function _setup_cog_env() {
+  _create_out_symlink_for_cog
+  if [ "$?" -eq "1" ]; then
+    echo -e "\e[0;33mWARNING:\e[00m Cog environment setup failed!"
+    return 1
+  fi
+  _copy_reclient_binaries_from_cog
+
+  export ANDROID_BUILD_ENVIRONMENT_CONFIG="googler-cog"
+
+  # Running repo command within Cog workspaces is not supported, so override
+  # it with this function. If the user is running repo within a Cog workspace,
+  # we'll fail with an error, otherwise, we run the original repo command with
+  # the given args.
+  ORIG_REPO_PATH=`which repo`
+  function repo {
+    if [[ "${PWD}" == /google/cog/* ]]; then
+      echo "\e[01;31mERROR:\e[0mrepo command is disallowed within Cog workspaces."
+      return 1
+    fi
+    ${ORIG_REPO_PATH} "$@"
+  }
+}
+
+if [[ "${PWD}" != /google/cog/* ]]; then
+  echo -e "\e[01;31mERROR:\e[0m This script must be run from a Cog workspace."
+fi
+
+_setup_cog_env