--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/streamlet-examples/streamlet-common.sh Sat Jan 11 19:15:58 2020 +0100
@@ -0,0 +1,116 @@
+#!/bin/bash
+
+# Relational pipes
+# Copyright © 2020 František Kučera (Frantovo.cz, GlobalCode.info)
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, version 3 of the License.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+
+# Unlike the protocol and the message format,
+# these helper functions are not part of the public API.
+# Thus when writing custom streamlets, it is better to copy this file
+# and review its changes while upgrading to new upstream version.
+
+
+send() {
+ local msgVar="EXEC_MSG_$1";
+ printf '%s\0' "${!msgVar}"
+ shift;
+ printf '%s\0' "$#"
+ for param in "$@"; do printf '%s\0' "$param"; done
+}
+
+read_nullbyte() { local IFS=; for v in "$@"; do export "$v"; read -r -d '' "$v"; done }
+
+processMessages() {
+ while read_nullbyte code length; do
+ local msgVar="EXEC_MSG_$code";
+ local functionName="processMessage_${!msgVar}";
+ local parameters=();
+ for (( i=0; i<$length; i++)); do
+ read_nullbyte parameter;
+ parameters+=("$parameter")
+ done
+ type "$functionName" &>/dev/null || functionName="processUnsupportedMessage";
+ "$functionName" "${parameters[@]}";
+ done
+}
+
+processUnsupportedMessage() {
+ echo "Unsupported message: $*" >&2
+ # TODO: send error, no debug
+ # send STREAMLET_ERROR "UNSUPPORTED_MESSAGE"
+}
+
+initialize() {
+ versionsSupported=();
+ optionNames=();
+ optionValues=();
+ inputAttributeNames=();
+ inputAttributeTypes=();
+ outputAttributeAliases=();
+ currentInputAttributeIndex=0;
+ currentOutputAttributeIndex=0;
+ currentRelation="";
+ currentFile="";
+}
+
+processMessage_VERSION_SUPPORTED() {
+ versionsSupported+=("$1");
+}
+
+processMessage_WAITING_FOR_VERSION() {
+ for v in "${versionsSupported[@]}"; do
+ if [[ "x$v" == "x1" ]]; then
+ send VERSION_ACCEPTED 1;
+ return;
+ fi
+ done
+ send STREAMLET_ERROR "INCOMPATIBLE_VERSION" "Only version 1 is supported by this streamlet."
+}
+
+processMessage_RELATION_START() {
+ currentRelation="$1";
+ return;
+}
+
+processMessage_INPUT_ATTRIBUTE_METADATA() {
+ inputAttributeNames+=("$1");
+ inputAttributeTypes+=("$2");
+}
+
+processMessage_OUTPUT_ATTRIBUTE_ALIAS() {
+ outputAttributeAliases+=("$1");
+}
+
+processMessage_OPTION() {
+ optionNames+=("$1");
+ optionValues+=("$2");
+}
+
+processMessage_INPUT_ATTRIBUTE() {
+ local index="$1";
+ local value="$2";
+ local isNull="$3";
+ if [[ "_${inputAttributeNames[$index]}" == "_path" ]]; then
+ currentFile="$value";
+ fi
+}
+
+processMessage_RELATION_END() {
+ # Now we should stop reading messages,
+ # but the executor also closes our STDIN,
+ # so the loop in processMessages() terminates.
+ # Override this function to do some clean-up.
+ return;
+}