上次我们聊到 CLI 的领域交互模式。在领域交互模式中，可能存在多层次的子命令。在使用过程中如果全评记忆的话，命令少还好，多了真心记不住。频繁 --help 也是个很麻烦的事情。如果每次按 'tab' 键就可以提示或补齐命令是不是很方便呢。这一节我们就来说说 'autocommplete' 如何实现。我们还是以interactcli-rs中的实现来解说实现过程
实现过程
其实，rustyline 已经为我们提供了基本的helper功能框架,其中包括了completer。我们来看代码，文件位置src/interact/cli.rs
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
|
#[derive(Helper)]
struct MyHelper {
completer: CommandCompleter,
highlighter: MatchingBracketHighlighter,
validator: MatchingBracketValidator,
hinter: HistoryHinter,
colored_prompt: String,
}
pub fn run() {
let config = Config::builder()
.history_ignore_space(true)
.completion_type(CompletionType::List)
.output_stream(OutputStreamType::Stdout)
.build();
let h = MyHelper {
completer: get_command_completer(),
highlighter: MatchingBracketHighlighter::new(),
hinter: HistoryHinter {},
colored_prompt: "".to_owned(),
validator: MatchingBracketValidator::new(),
};
let mut rl = Editor::with_config(config);
// let mut rl = Editor::<()>::new();
rl.set_helper(Some(h));
......
}
|
首先定义 MyHelper 结构体， 需要实现 Completer + Hinter + Highlighter + Validator trait。然后通过rustyline的set_helper函数加载我们定义好的helper。在MyHelper 结构体中，需要我们自己来实现completer的逻辑。
Sub command autocompleter实现详解
- SubCmd 结构体
|
1
2
3
4
5
6
|
#[derive(Debug, Clone)]
pub struct SubCmd {
pub level: usize,
pub command_name: String,
pub subcommands: Vec<String>,
}
|
SubCmd 结构体包含：命令级别，命令名称，以及该命令包含的子命令信息，以便在实现实现 autocomplete 时定位命令和子命令的范围
- 在程序启动时遍历所有的command，src/cmd/rootcmd.rs 中的all_subcommand函数负责收集所有命令并转换为Vec<SubCmd>
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
|
pub fn all_subcommand(app: &clap_Command, beginlevel: usize, input: &mut Vec<SubCmd>) {
let nextlevel = beginlevel + 1;
let mut subcmds = vec![];
for iterm in app.get_subcommands() {
subcmds.push(iterm.get_name().to_string());
if iterm.has_subcommands() {
all_subcommand(iterm, nextlevel, input);
} else {
if beginlevel == 0 {
all_subcommand(iterm, nextlevel, input);
}
}
}
let subcommand = SubCmd {
level: beginlevel,
command_name: app.get_name().to_string(),
subcommands: subcmds,
};
input.push(subcommand);
}
|
- CommandCompleter 子命令自动补充功能的核心部分
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
|
#[derive(Debug, Clone)]
pub struct CommandCompleter {
subcommands: Vec<SubCmd>,
}
impl CommandCompleter {
pub fn new(subcmds: Vec<SubCmd>) -> Self {
Self {
subcommands: subcmds,
}
}
//获取level下所有可能的子命令
pub fn level_possible_cmd(&self, level: usize) -> Vec<String> {
let mut subcmds = vec![];
let cmds = self.subcommands.clone();
for iterm in cmds {
if iterm.level == level {
subcmds.push(iterm.command_name.clone());
}
}
return subcmds;
}
//获取level下某字符串开头的子命令
pub fn level_prefix_possible_cmd(&self, level: usize, prefix: &str) -> Vec<String> {
let mut subcmds = vec![];
let cmds = self.subcommands.clone();
for iterm in cmds {
if iterm.level == level && iterm.command_name. starts_with(prefix) {
subcmds.push(iterm.command_name);
}
}
return subcmds;
}
//获取某level 下某subcommand的所有子命令
pub fn level_cmd_possible_sub_cmd(&self, level: usize, cmd: String) -> Vec<String> {
let mut subcmds = vec![];
let cmds = self.subcommands.clone();
for iterm in cmds {
if iterm.level == level && iterm.command_name == cmd {
subcmds = iterm.subcommands.clone();
}
}
return subcmds;
}
//获取某level 下某subcommand的所有prefix子命令
pub fn level_cmd_possible_prefix_sub_cmd(
&self,
level: usize,
cmd: String,
prefix: &str,
) -> Vec<String> {
let mut subcmds = vec![];
let cmds = self.subcommands.clone();
for iterm in cmds {
if iterm.level == level && iterm.command_name == cmd {
for i in iterm.subcommands {
if i.starts_with(prefix) {
subcmds.push(i);
}
}
}
}
return subcmds;
}
pub fn complete_cmd(&self, line: &str, pos: usize) -> Result<(usize, Vec<Pair>)> {
let mut entries: Vec<Pair> = Vec::new();
let d: Vec<_> = line.split(' ').collect();
if d.len() == 1 {
if d.last() == Some(&"") {
for str in self.level_possible_cmd(1) {
let mut replace = str.clone();
replace.push_str(" ");
entries.push(Pair {
display: str.clone(),
replacement: replace,
});
}
return Ok((pos, entries));
}
if let Some(last) = d.last() {
for str in self.level_prefix_possible_cmd (1, *last) {
let mut replace = str.clone();
replace.push_str(" ");
entries.push(Pair {
display: str.clone(),
replacement: replace,
});
}
return Ok((pos - last.len(), entries));
}
}
if d.last() == Some(&"") {
for str in self
.level_cmd_possible_sub_cmd(d.len() - 1, d.get(d.len() - 2).unwrap().to_string())
{
let mut replace = str.clone();
replace.push_str(" ");
entries.push(Pair {
display: str.clone(),
replacement: replace,
});
}
return Ok((pos, entries));
}
if let Some(last) = d.last() {
for str in self. level_cmd_possible_prefix_sub_cmd(
d.len() - 1,
d.get(d.len() - 2).unwrap().to_string(),
*last,
) {
let mut replace = str.clone();
replace.push_str(" ");
entries.push(Pair {
display: str.clone(),
replacement: replace,
});
}
return Ok((pos - last.len(), entries));
}
Ok((pos, entries))
}
}
impl Completer for CommandCompleter {
type Candidate = Pair;
fn complete(&self, line: &str, pos: usize, _ctx: & Context<'_>) -> Result<(usize, Vec<Pair>)> {
self.complete_cmd(line, pos)
}
}
|
CommandCompleter 的实现部分比较多，大致包括两个部分，前一部分包括：获取某一级别下所有可能的子命令、获取某级别下某字符串开头的子命令、获取某级别下某个命令的所有子命令，等基本功能。这部分代码中有注释就不一一累述。
函数complete_cmd用来计算行中的位置以及在该位置的替换内容。
输入项是命令行的内容以及光标所在位置，输出项为在该位置需要替换的内容。比如，我们在提示符下输入 "root cm" root 下包含 cmd1、cmd2 两个子命令，此时如果按 'tab'键，complete_cmd 函数就会返回 (7,[cmd1,cmd2])。
作者：京东科技 贾世闻
来源：京东云开发者社区 转载请注明来源
本文含有隐藏内容，请 开通VIP 后查看