Initial import

.github/workflows/test.yaml

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+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 .

README.md

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+# 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 SIGNAL CMD`
+
+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.

test.bats

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+#!/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 $BATS_TEST_DIRNAME/trap.sh
+  trap_append USR2 \"echo 'USR2 signal received'\"
+  kill -s USR2 \$\$
+  ")" 'USR2 signal received'
+}
+
+@test 'trap removal works' {
+  assert_equal "$(bash -ec "source $BATS_TEST_DIRNAME/trap.sh
+  trap_append USR2 \"echo 'cmd to remove'\"
+  p=\$TRAP_POINTER
+  trap_append USR2 \"echo 'USR2 signal received'\"
+  trap_remove \$p
+  kill -s USR2 \$\$
+  ")" 'USR2 signal received'
+}
+
+@test 'only commands for specific signal are run' {
+  assert_equal "$(bash -ec "source $BATS_TEST_DIRNAME/trap.sh
+  trap_append USR1 \"echo 'USR1 signal received'\"
+  trap_append USR2 \"echo 'USR2 signal received'\"
+  kill -s USR2 \$\$
+  ")" 'USR2 signal received'
+}

trap.sh

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+#!/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 signal=$1 cmd=$2 trap_cmd
+  TRAP_POINTER=0
+  for trap_cmd in "${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]=''
+}

upkg.json

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+{
+  "assets": ["trap.sh"]
+}