Handle nested subvolumes & remove broken git exclusion

src/interval.sh

@@ -0,0 +1,88 @@
+#!/bin/bash
+
+# Return whole seconds and a fractional part without floating-point rounding.
+# Long multiplication keeps the range checks exact even for tiny fractions.
+interval_duration() {
+    local value=$1 whole fraction multiplier carry=0 product='' digit index
+    if [[ ! $value =~ ^([0-9]+([.][0-9]*)?|[.][0-9]+)([smhd]?)$ ]]; then
+        echo 'SLEEP_TIME must be a positive duration in seconds, minutes, hours or days.' >&2
+        return 1
+    fi
+    case ${BASH_REMATCH[3]} in
+        ''|s) multiplier=1 ;;
+        m) multiplier=60 ;;
+        h) multiplier=3600 ;;
+        d) multiplier=86400 ;;
+    esac
+    value=${BASH_REMATCH[1]}
+    whole=${value%%.*}
+    whole=${whole#"${whole%%[!0]*}"}
+    whole=${whole:-0}
+    if (( ${#whole} > 10 )); then
+        echo 'SLEEP_TIME must represent between 1 and 2147483647 seconds.' >&2
+        return 1
+    fi
+    fraction=''
+    [[ $value != *.* ]] || fraction=${value#*.}
+    for ((index = ${#fraction} - 1; index >= 0; index--)); do
+        digit=$((10#${fraction:index:1} * multiplier + carry))
+        product="$((digit % 10))$product"
+        carry=$((digit / 10))
+    done
+    whole=$((10#$whole * multiplier + carry))
+    product=${product%"${product##*[!0]}"}
+    if (( whole < 1 || whole > 2147483647 )) || { (( whole == 2147483647 )) && [[ -n $product ]]; }; then
+        echo 'SLEEP_TIME must represent between 1 and 2147483647 seconds.' >&2
+        return 1
+    fi
+    printf '%s %s\n' "$whole" "${product:-0}"
+}
+
+# /proc/uptime advances independently of wall-clock adjustments, in 10 ms ticks.
+interval_now() {
+    local uptime _idle whole fraction
+    read -r uptime _idle < /proc/uptime || return 1
+    whole=${uptime%.*}
+    fraction=${uptime#*.}00
+    printf '%s\n' "$((10#$whole * 100 + 10#${fraction:0:2}))"
+}
+
+interval_budget() {
+    local duration
+    duration=$(interval_duration "$1") || return 1
+    printf '%s\n' "${duration%% *}"
+}
+
+interval_deadline() {
+    local duration whole fraction ticks now
+    duration=$(interval_duration "$1") || return 1
+    read -r whole fraction <<< "$duration"
+    fraction+='00'
+    ticks=$((whole * 100 + 10#${fraction:0:2}))
+    # Round up fractions and the current clock tick to preserve the minimum wait.
+    [[ ${fraction:2} != *[1-9]* ]] || ticks=$((ticks + 1))
+    now=$(interval_now) || return 1
+    printf '%s\n' "$((now + ticks + 1))"
+}
+
+interval_wait() {
+    local deadline=$1 now remaining delay
+    [[ $deadline =~ ^[0-9]{1,15}$ ]] || return 1
+    while true; do
+        now=$(interval_now) || return 1
+        remaining=$((10#$deadline - now))
+        (( remaining > 0 )) || return 0
+        printf -v delay '%d.%02d' "$((remaining / 100))" "$((remaining % 100))"
+        sleep "$delay" || return 1
+    done
+}
+
+if [[ ${BASH_SOURCE[0]} == "$0" ]]; then
+    case ${1:-} in
+        budget|deadline|wait)
+            [[ $# == 2 ]] || exit 1
+            "interval_$1" "$2"
+            ;;
+        *) echo 'Expected budget, deadline or wait and a value.' >&2; exit 1 ;;
+    esac
+fi