forked from apple/swift-argument-parser
/
BashCompletionsGenerator.swift
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/
BashCompletionsGenerator.swift
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//===----------------------------------------------------------*- swift -*-===//
//
// This source file is part of the Swift Argument Parser open source project
//
// Copyright (c) 2020 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
//
//===----------------------------------------------------------------------===//
struct BashCompletionsGenerator {
/// Generates a Bash completion script for the given command.
static func generateCompletionScript(_ type: ParsableCommand.Type) -> String {
// TODO: Add a check to see if the command is installed where we expect?
let initialFunctionName = [type].completionFunctionName()
return """
#!/bin/bash
\(generateCompletionFunction([type]))
complete -F \(initialFunctionName) \(type._commandName)
"""
}
/// Generates a Bash completion function for the last command in the given list.
fileprivate static func generateCompletionFunction(_ commands: [ParsableCommand.Type]) -> String {
let type = commands.last!
let functionName = commands.completionFunctionName()
// The root command gets a different treatment for the parsing index.
let isRootCommand = commands.count == 1
let dollarOne = isRootCommand ? "1" : "$1"
let subcommandArgument = isRootCommand ? "2" : "$(($1+1))"
// Include 'help' in the list of subcommands for the root command.
var subcommands = type.configuration.subcommands
.filter { $0.configuration.shouldDisplay }
if !subcommands.isEmpty && isRootCommand {
subcommands.append(HelpCommand.self)
}
// Generate the words that are available at the "top level" of this
// command — these are the dash-prefixed names of options and flags as well
// as all the subcommand names.
let completionWords = generateArgumentWords(commands)
+ subcommands.map { $0._commandName }
// Generate additional top-level completions — these are completion lists
// or custom function-based word lists from positional arguments.
let additionalCompletions = generateArgumentCompletions(commands)
// Start building the resulting function code.
var result = "\(functionName)() {\n"
// The function that represents the root command has some additional setup
// that other command functions don't need.
if isRootCommand {
result += """
cur="${COMP_WORDS[COMP_CWORD]}"
prev="${COMP_WORDS[COMP_CWORD-1]}"
COMPREPLY=()
""".indentingEachLine(by: 4)
}
// Start by declaring a local var for the top-level completions.
// Return immediately if the completion matching hasn't moved further.
result += " opts=\"\(completionWords.joined(separator: " "))\"\n"
for line in additionalCompletions {
result += " opts=\"$opts \(line)\"\n"
}
result += """
if [[ $COMP_CWORD == "\(dollarOne)" ]]; then
COMPREPLY=( $(compgen -W "$opts" -- "$cur") )
return
fi
"""
// Generate the case pattern-matching statements for option values.
// If there aren't any, skip the case block altogether.
let optionHandlers = generateOptionHandlers(commands)
if !optionHandlers.isEmpty {
result += """
case $prev in
\(optionHandlers.indentingEachLine(by: 4))
esac
""".indentingEachLine(by: 4) + "\n"
}
// Build out completions for the subcommands.
if !subcommands.isEmpty {
// Subcommands have their own case statement that delegates out to
// the subcommand completion functions.
result += " case ${COMP_WORDS[\(dollarOne)]} in\n"
for subcommand in subcommands {
result += """
(\(subcommand._commandName))
\(functionName)_\(subcommand._commandName) \(subcommandArgument)
return
;;
"""
.indentingEachLine(by: 8)
}
result += " esac\n"
}
// Finish off the function.
result += """
COMPREPLY=( $(compgen -W "$opts" -- "$cur") )
}
"""
return result +
subcommands
.map { generateCompletionFunction(commands + [$0]) }
.joined()
}
/// Returns the option and flag names that can be top-level completions.
fileprivate static func generateArgumentWords(_ commands: [ParsableCommand.Type]) -> [String] {
commands
.argumentsForHelp(visibility: .default)
.flatMap { $0.bashCompletionWords() }
}
/// Returns additional top-level completions from positional arguments.
///
/// These consist of completions that are defined as `.list` or `.custom`.
fileprivate static func generateArgumentCompletions(_ commands: [ParsableCommand.Type]) -> [String] {
ArgumentSet(commands.last!, visibility: .default, parent: .root)
.compactMap { arg -> String? in
guard arg.isPositional else { return nil }
switch arg.completion.kind {
case .default, .file, .directory:
return nil
case .list(let list):
return list.joined(separator: " ")
case .shellCommand(let command):
return "$(\(command))"
case .custom:
// Generate a call back into the command to retrieve a completions list
let subcommandNames = commands.dropFirst().map { $0._commandName }.joined(separator: " ")
// TODO: Make this work for @Arguments
let argumentName = arg.names.preferredName?.synopsisString
?? arg.help.keys.first?.name ?? "---"
return """
$("${COMP_WORDS[0]}" ---completion \(subcommandNames) -- \(argumentName) "${COMP_WORDS[@]}")
"""
}
}
}
/// Returns the case-matching statements for supplying completions after an option or flag.
fileprivate static func generateOptionHandlers(_ commands: [ParsableCommand.Type]) -> String {
ArgumentSet(commands.last!, visibility: .default, parent: .root)
.compactMap { arg -> String? in
let words = arg.bashCompletionWords()
if words.isEmpty { return nil }
// Flags don't take a value, so we don't provide follow-on completions.
if arg.isNullary { return nil }
return """
\(arg.bashCompletionWords().joined(separator: "|")))
\(arg.bashValueCompletion(commands).indentingEachLine(by: 4))
return
;;
"""
}
.joined(separator: "\n")
}
}
extension ArgumentDefinition {
/// Returns the different completion names for this argument.
fileprivate func bashCompletionWords() -> [String] {
return help.visibility.base == .default
? names.map { $0.synopsisString }
: []
}
/// Returns the bash completions that can follow this argument's `--name`.
fileprivate func bashValueCompletion(_ commands: [ParsableCommand.Type]) -> String {
switch completion.kind {
case .default:
return ""
case .file(_):
// TODO: Use '_filedir' when available
// FIXME: Use the extensions array
return #"COMPREPLY=( $(compgen -f -- "$cur") )"#
case .directory:
return #"COMPREPLY=( $(compgen -d -- "$cur") )"#
case .list(let list):
return #"COMPREPLY=( $(compgen -W "\#(list.joined(separator: " "))" -- "$cur") )"#
case .shellCommand(let command):
return "COMPREPLY=( $(\(command)) )"
case .custom:
// Generate a call back into the command to retrieve a completions list
return #"COMPREPLY=( $(compgen -W "$("${COMP_WORDS[0]}" \#(customCompletionCall(commands)) "${COMP_WORDS[@]}")" -- "$cur") )"#
}
}
}