prelude: bring substituteInPlace from nixpkgs stdenv because its awesome

Signed-off-by: lucasew <lucas59356@gmail.com>

bin/prelude/010-stdenv-utils.sh

@@ -0,0 +1,117 @@
+
+
+substituteStream() {
+    local var=$1
+    local description=$2
+    shift 2
+
+    while (( "$#" )); do
+        local replace_mode="$1"
+        case "$1" in
+            --replace)
+                # deprecated 2023-11-22
+                # this will either get removed, or switch to the behaviour of --replace-fail in the future
+                if ! "$_substituteStream_has_warned_replace_deprecation"; then
+                    echo "substituteStream() in derivation $name: WARNING: '--replace' is deprecated, use --replace-{fail,warn,quiet}. ($description)" >&2
+                    _substituteStream_has_warned_replace_deprecation=true
+                fi
+                replace_mode='--replace-warn'
+                ;&
+            --replace-quiet|--replace-warn|--replace-fail)
+                pattern="$2"
+                replacement="$3"
+                shift 3
+                local savedvar
+                savedvar="${!var}"
+                eval "$var"'=${'"$var"'//"$pattern"/"$replacement"}'
+                if [ "$pattern" != "$replacement" ]; then
+                    if [ "${!var}" == "$savedvar" ]; then
+                        if [ "$replace_mode" == --replace-warn ]; then
+                            printf "substituteStream() in derivation $name: WARNING: pattern %q doesn't match anything in %s\n" "$pattern" "$description" >&2
+                        elif [ "$replace_mode" == --replace-fail ]; then
+                            printf "substituteStream() in derivation $name: ERROR: pattern %q doesn't match anything in %s\n" "$pattern" "$description" >&2
+                            return 1
+                        fi
+                    fi
+                fi
+                ;;
+
+            --subst-var)
+                local varName="$2"
+                shift 2
+                # check if the used nix attribute name is a valid bash name
+                if ! [[ "$varName" =~ ^[a-zA-Z_][a-zA-Z0-9_]*$ ]]; then
+                    echo "substituteStream() in derivation $name: ERROR: substitution variables must be valid Bash names, \"$varName\" isn't." >&2
+                    return 1
+                fi
+                if [ -z ${!varName+x} ]; then
+                    echo "substituteStream() in derivation $name: ERROR: variable \$$varName is unset" >&2
+                    return 1
+                fi
+                pattern="@$varName@"
+                replacement="${!varName}"
+                eval "$var"'=${'"$var"'//"$pattern"/"$replacement"}'
+                ;;
+
+            --subst-var-by)
+                pattern="@$2@"
+                replacement="$3"
+                eval "$var"'=${'"$var"'//"$pattern"/"$replacement"}'
+                shift 3
+                ;;
+
+            *)
+                echo "substituteStream() in derivation $name: ERROR: Invalid command line argument: $1" >&2
+                return 1
+                ;;
+        esac
+    done
+
+    printf "%s" "${!var}"
+}
+
+# put the content of a file in a variable
+# fail loudly if provided with a binary (containing null bytes)
+consumeEntire() {
+    # read returns non-0 on EOF, so we want read to fail
+    if IFS='' read -r -d '' "$1" ; then
+        echo "consumeEntire(): ERROR: Input null bytes, won't process" >&2
+        return 1
+    fi
+}
+
+substitute() {
+    local input="$1"
+    local output="$2"
+    shift 2
+
+    if [ ! -f "$input" ]; then
+        echo "substitute(): ERROR: file '$input' does not exist" >&2
+        return 1
+    fi
+
+    local content
+    consumeEntire content < "$input"
+
+    if [ -e "$output" ]; then chmod +w "$output"; fi
+    substituteStream content "file '$input'" "$@" > "$output"
+}
+
+substituteInPlace() {
+    local -a fileNames=()
+    for arg in "$@"; do
+        if [[ "$arg" = "--"* ]]; then
+            break
+        fi
+        fileNames+=("$arg")
+        shift
+    done
+    if ! [[ "${#fileNames[@]}" -gt 0 ]]; then
+        echo >&2 "substituteInPlace called without any files to operate on (files must come before options!)"
+        return 1
+    fi
+
+    for file in "${fileNames[@]}"; do
+        substitute "$file" "$file" "$@"
+    done
+}