turbopack_ecmascript/references/esm/
meta.rs

1use std::borrow::Cow;
2
3use anyhow::Result;
4use serde::{Deserialize, Serialize};
5use swc_core::{
6    common::DUMMY_SP,
7    ecma::ast::{Expr, Ident},
8    quote,
9};
10use turbo_rcstr::rcstr;
11use turbo_tasks::{NonLocalValue, Vc, debug::ValueDebugFormat, trace::TraceRawVcs};
12use turbo_tasks_fs::FileSystemPath;
13use turbopack_core::chunk::ChunkingContext;
14
15use crate::{
16    code_gen::{CodeGen, CodeGeneration},
17    create_visitor, magic_identifier,
18    references::AstPath,
19    runtime_functions::TURBOPACK_RESOLVE_ABSOLUTE_PATH,
20};
21
22/// Responsible for initializing the `import.meta` object binding, so that it
23/// may be referenced in th the file.
24///
25/// There can be many references to import.meta, and they appear at any nesting
26/// in the file. But we must only initialize the binding a single time.
27///
28/// This singleton behavior must be enforced by the caller!
29#[derive(PartialEq, Eq, Serialize, Deserialize, TraceRawVcs, ValueDebugFormat, NonLocalValue)]
30pub struct ImportMetaBinding {
31    path: FileSystemPath,
32}
33
34impl ImportMetaBinding {
35    pub fn new(path: FileSystemPath) -> Self {
36        ImportMetaBinding { path }
37    }
38
39    pub async fn code_generation(
40        &self,
41        chunking_context: Vc<Box<dyn ChunkingContext>>,
42    ) -> Result<CodeGeneration> {
43        let rel_path = chunking_context
44            .root_path()
45            .await?
46            .get_relative_path_to(&self.path);
47        let path = rel_path.map_or_else(
48            || {
49                quote!(
50                    "(() => { throw new Error('could not convert import.meta.url to filepath') })()"
51                        as Expr
52                )
53            },
54            |path| {
55                let formatted = encode_path(path.trim_start_matches("./")).to_string();
56                quote!(
57                    "`file://${$turbopack_resolve_absolute_path($formatted)}`" as Expr,
58                    turbopack_resolve_absolute_path: Expr = TURBOPACK_RESOLVE_ABSOLUTE_PATH.into(),
59                    formatted: Expr = formatted.into()
60                )
61            },
62        );
63
64        Ok(CodeGeneration::hoisted_stmt(
65            rcstr!("import.meta"),
66            // [NOTE] url property is lazy-evaluated, as it should be computed once
67            // turbopack_runtime injects a function to calculate an absolute path.
68            quote!(
69                "const $name = { get url() { return $path } };" as Stmt,
70                name = meta_ident(),
71                path: Expr = path.clone(),
72            ),
73        ))
74    }
75}
76
77impl From<ImportMetaBinding> for CodeGen {
78    fn from(val: ImportMetaBinding) -> Self {
79        CodeGen::ImportMetaBinding(val)
80    }
81}
82
83/// Handles rewriting `import.meta` references into the injected binding created
84/// by ImportMetaBinding.
85///
86/// There can be many references to import.meta, and they appear at any nesting
87/// in the file. But all references refer to the same mutable object.
88#[derive(PartialEq, Eq, Serialize, Deserialize, TraceRawVcs, ValueDebugFormat, NonLocalValue)]
89pub struct ImportMetaRef {
90    ast_path: AstPath,
91}
92
93impl ImportMetaRef {
94    pub fn new(ast_path: AstPath) -> Self {
95        ImportMetaRef { ast_path }
96    }
97
98    pub async fn code_generation(
99        &self,
100        _chunking_context: Vc<Box<dyn ChunkingContext>>,
101    ) -> Result<CodeGeneration> {
102        let visitor = create_visitor!(self.ast_path, visit_mut_expr, |expr: &mut Expr| {
103            *expr = Expr::Ident(meta_ident());
104        });
105
106        Ok(CodeGeneration::visitors(vec![visitor]))
107    }
108}
109
110impl From<ImportMetaRef> for CodeGen {
111    fn from(val: ImportMetaRef) -> Self {
112        CodeGen::ImportMetaRef(val)
113    }
114}
115
116/// URL encodes special chars that would appear in the "pathname" portion.
117/// https://github.com/nodejs/node/blob/3bed5f11e039153eff5cbfd9513b8f55fd53fc43/lib/internal/url.js#L1513-L1526
118fn encode_path(path: &'_ str) -> Cow<'_, str> {
119    let mut encoded = String::new();
120    let mut start = 0;
121    for (i, c) in path.char_indices() {
122        let mapping = match c {
123            '%' => "%25",
124            '\\' => "%5C",
125            '\n' => "%0A",
126            '\r' => "%0D",
127            '\t' => "%09",
128            _ => continue,
129        };
130
131        if encoded.is_empty() {
132            encoded.reserve(path.len());
133        }
134
135        encoded += &path[start..i];
136        encoded += mapping;
137        start = i + 1;
138    }
139
140    if encoded.is_empty() {
141        return Cow::Borrowed(path);
142    }
143    encoded += &path[start..];
144    Cow::Owned(encoded)
145}
146
147fn meta_ident() -> Ident {
148    Ident::new(
149        magic_identifier::mangle("import.meta").into(),
150        DUMMY_SP,
151        Default::default(),
152    )
153}
154
155#[cfg(test)]
156mod test {
157    use super::encode_path;
158
159    #[test]
160    fn test_encode_path_regular() {
161        let input = "abc";
162        assert_eq!(encode_path(input), "abc");
163    }
164
165    #[test]
166    fn test_encode_path_special_chars() {
167        let input = "abc%def\\ghi\njkl\rmno\tpqr";
168        assert_eq!(encode_path(input), "abc%25def%5Cghi%0Ajkl%0Dmno%09pqr");
169    }
170
171    #[test]
172    fn test_encode_path_special_char_start() {
173        let input = "%abc";
174        assert_eq!(encode_path(input), "%25abc");
175    }
176
177    #[test]
178    fn test_encode_path_special_char_end() {
179        let input = "abc%";
180        assert_eq!(encode_path(input), "abc%25");
181    }
182
183    #[test]
184    fn test_encode_path_special_char_contiguous() {
185        let input = "%%%";
186        assert_eq!(encode_path(input), "%25%25%25");
187    }
188}
turbopack_ecmascript/references/esm/meta.rs

turbopack_ecmascript/references/esm/
meta.rs
