From 43224f40fef2d0f5040561af11b5d1e87dc67034 Mon Sep 17 00:00:00 2001
From: Anders Ingemann <aim@orbit.online>
Date: Wed, 21 Feb 2024 12:57:56 +0100
Subject: [PATCH] Initial import

---
 .github/workflows/test.yaml | 35 +++++++++++++++++++++++++++++++++++
 README.md                   | 27 +++++++++++++++++++++++++++
 test.bats                   | 34 ++++++++++++++++++++++++++++++++++
 trap.sh                     | 28 ++++++++++++++++++++++++++++
 upkg.json                   |  3 +++
 5 files changed, 127 insertions(+)
 create mode 100644 .github/workflows/test.yaml
 create mode 100644 README.md
 create mode 100644 test.bats
 create mode 100644 trap.sh
 create mode 100644 upkg.json

diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
new file mode 100644
index 0000000..da8d73b
--- /dev/null
+++ b/.github/workflows/test.yaml
@@ -0,0 +1,35 @@
+name: Test
+
+on:
+  push:
+    branches: [ '*' ]
+    tags: [ 'v*' ]
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v3
+    - name: Run ShellCheck
+      uses: ludeeus/action-shellcheck@master
+      env:
+        SHELLCHECK_OPTS: -x
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Setup BATS
+      run: |
+        git clone --depth 1 --branch v1.10.0 https://github.com/bats-core/bats-core.git /tmp/bats
+        sudo /tmp/bats/install.sh /usr/local
+        rm -rf /tmp/bats
+        sudo mkdir -p /usr/lib/bats/bats-support /usr/lib/bats/bats-assert
+        wget -O- 'https://github.com/ztombol/bats-support/archive/refs/tags/v0.3.0.tar.gz' | \
+          sudo tar -xz --strip-components=1 -C /usr/lib/bats/bats-support
+        wget -O- 'https://github.com/ztombol/bats-assert/archive/refs/tags/v0.3.0.tar.gz' | \
+          sudo tar -xz --strip-components=1 -C /usr/lib/bats/bats-assert
+    - name: Checkout
+      uses: actions/checkout@v3
+    - uses: orbit-online/upkg@v0.14.0
+    - name: Run tests
+      run: bats .
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..bbab313
--- /dev/null
+++ b/README.md
@@ -0,0 +1,27 @@
+# trap.sh
+
+Library for managing bash signal traps.
+
+## Contents
+
+- [Installation](#installation)
+- [Usage](#usage)
+
+## Installation
+
+With [μpkg](https://github.com/orbit-online/upkg)
+
+```
+upkg install -g orbit-online/trap.sh@<VERSION>
+```
+
+## Usage
+
+### `trap_append CMD SIGNAL`
+
+Appends `CMD` to the `SIGNAL` trap. `$TRAP_POINTER` will contain a pointer
+that can be used with `trap_remove` to remove the command again.
+
+### `trap_remove POINTER`
+
+Removes the command identified by `POINTER` from the list of traps to run.
diff --git a/test.bats b/test.bats
new file mode 100644
index 0000000..1b4a6b4
--- /dev/null
+++ b/test.bats
@@ -0,0 +1,34 @@
+#!/usr/bin/env bats
+# shellcheck disable=2030,2031
+
+load '/usr/lib/bats/bats-support/load'
+load '/usr/lib/bats/bats-assert/load'
+
+setup_file() {
+  bats_require_minimum_version 1.5.0
+}
+
+@test 'trap is run on signal' {
+  assert_equal "$(bash -ec "source $BATS_TEST_DIRNAME/trap.sh
+  trap_append \"echo 'USR2 signal received'\" USR2
+  kill -s USR2 \$\$
+  ")" 'USR2 signal received'
+}
+
+@test 'trap removal works' {
+  assert_equal "$(bash -ec "source $BATS_TEST_DIRNAME/trap.sh
+  trap_append \"echo 'cmd to remove'\" USR2
+  p=\$TRAP_POINTER
+  trap_append \"echo 'USR2 signal received'\" USR2
+  trap_remove \$p
+  kill -s USR2 \$\$
+  ")" 'USR2 signal received'
+}
+
+@test 'only commands for specific signal are run' {
+  assert_equal "$(bash -ec "source $BATS_TEST_DIRNAME/trap.sh
+  trap_append \"echo 'USR1 signal received'\" USR1
+  trap_append \"echo 'USR2 signal received'\" USR2
+  kill -s USR2 \$\$
+  ")" 'USR2 signal received'
+}
diff --git a/trap.sh b/trap.sh
new file mode 100644
index 0000000..d0ce3db
--- /dev/null
+++ b/trap.sh
@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+
+TRAP_CMDS=()
+
+_trap_run() {
+  local signal=$1 trap_cmd
+  for trap_cmd in "${TRAP_CMDS[@]}"; do
+    [[ $trap_cmd = $signal* ]] || continue
+    eval "${trap_cmd#"$signal "}" || true
+  done
+}
+
+trap_append() {
+  local cmd=$1 signal=$2 trap_cmd
+  TRAP_POINTER=0
+  for trap_cmd in "${TRAP_CMDS[@]}"; do
+    [[ -n $trap_cmd ]] || break
+    : $((TRAP_POINTER++))
+  done
+  TRAP_CMDS[TRAP_POINTER]="$signal $cmd"
+  # shellcheck disable=SC2064
+  [[ $(trap -p "$signal") = "trap -- '_trap_run $signal' $signal" ]] || trap "_trap_run $signal" "$signal"
+}
+
+trap_remove() {
+  local pointer=$1
+  TRAP_CMDS[pointer]=''
+}
diff --git a/upkg.json b/upkg.json
new file mode 100644
index 0000000..231a948
--- /dev/null
+++ b/upkg.json
@@ -0,0 +1,3 @@
+{
+  "assets": ["trap.sh"]
+}