build_library: add torcx_manifest helper

This implements some basic functionality around working with torcx
manifests.

build_library/torcx_manifest.sh

@@ -0,0 +1,97 @@
+# Copyright (c) 2017 The Container Linux by CoreOS Authors. All rights
+# reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# torcx_manifest.sh contains helper functions for creating, editing, and
+# reading torcx manifest files.
+
+# create_empty creates an empty torcx manfiest at the given path.
+function torcx_manifest::create_empty() {
+  local path="${1}"
+  jq '.' > "${path}" <<EOF
+{
+  "kind": "torcx-package-list-v0",
+  "value": {
+    "packages": []
+  }
+}
+EOF
+}
+
+# add_pkg adds a new version of a package to the torcx manifest specified by
+# path.
+# That manifest will be edited to include this version, with the associated
+# package of the given name being created as well if necessary.
+function torcx_manifest::add_pkg() {
+  path="${1}"; shift
+  name="${1}"; shift
+  version="${1}"; shift
+  pkg_hash="${1}"; shift
+  cas_digest="${1}"; shift
+  source_package="${1}"; shift
+  update_default="${1}"; shift
+
+  local manifest=$(cat "${path}")
+  local pkg_version_obj=$(jq '.' <<EOF
+{
+  "version": "${version}",
+  "hash": "${pkg_hash}",
+  "casDigest": "${cas_digest}",
+  "sourcePackage": "${source_package}",
+  "locations": []
+}
+EOF
+)
+
+  for location in "${@}"; do
+    if [[ "${location}" == /* ]]; then
+      # filepath
+      pkg_version_obj=$(jq ".locations |= . + [{\"path\": \"${location}\"}]" <(echo "${pkg_version_obj}"))
+    else
+      # url
+      pkg_version_obj=$(jq ".locations |= . + [{\"url\": \"${location}\"}]" <(echo "${pkg_version_obj}"))
+    fi
+  done
+
+
+  local existing_pkg="$(echo "${manifest}" | jq ".value.packages[] | select(.name == \"${name}\")")"
+
+  # If there isn't yet a package in the manifest for $name, initialize it to an empty one.
+  if [[ "${existing_pkg}" == "" ]]; then
+    pkg_json=$(cat <<EOF
+    {
+      "name": "${name}",
+      "versions": []
+    }
+EOF
+)
+    manifest="$(echo "${manifest}" | jq ".value.packages |= . + [${pkg_json}]")"
+  fi
+
+  if [[ "${update_default}" == "true" ]]; then
+    manifest="$(echo "${manifest}" | jq "(.value.packages[] | select(.name = \"${name}\") | .defaultVersion) |= \"${version}\"")"
+  fi
+
+  # append this specific package version to the manifest
+  manifest="$(echo "${manifest}" | jq "(.value.packages[] | select(.name = \"${name}\") | .versions) |= . + [${pkg_version_obj}]")"
+
+  echo "${manifest}" | jq '.' > "${path}"
+}
+
+# get_pkg_names returns the list of packages in a given manifest. Each package
+# may have one or more versions associated with it.
+#
+# Example:
+#     pkg_name_arr=($(torcx_manifest::get_pkg_names "torcx_manifest.json"))
+function torcx_manifest::get_pkg_names() {
+  local file="${1}"
+  jq -r '.value.packages[].name' < "${file}"
+}
+
+# get_digests returns the list of digests for a given package. 
+function torcx_manifest::get_digests() {
+  local file="${1}"
+  local name="${2}"
+  jq -r ".value.packages[] | select(.name == \"${name}\").versions[].casDigest" < "${file}"
+}