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
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160

//! The definition of a WASM interface

use std::collections::HashMap;

#[derive(Debug, Clone, PartialEq, Eq, Default)]
pub struct Interface {
    /// Things that the module can import
    pub imports: HashMap<(String, String), Import>,
    /// Things that the module must export
    pub exports: HashMap<String, Export>,
}

impl Interface {
    pub fn merge(&self, other: Interface) -> Result<Interface, String> {
        let mut base = self.clone();

        for (key, val) in other.imports.into_iter() {
            if base.imports.contains_key(&key) {
                if val != base.imports[&key] {
                    return Err(format!("Conflict detected: the import \"{}\" \"{}\" was found but the definitions were different: {:?} {:?}", &key.0, &key.1, base.imports[&key], val));
                }
            } else {
                let res = base.imports.insert(key, val);
                debug_assert!(res.is_none());
            }
        }

        for (key, val) in other.exports.into_iter() {
            if base.exports.contains_key(&key) {
                if val != base.exports[&key] {
                    return Err(format!("Conflict detected: the key {} was found in exports but the definitions were different: {:?} {:?}", key, base.exports[&key], val));
                }
            } else {
                let res = base.exports.insert(key, val);
                debug_assert!(res.is_none());
            }
        }
        Ok(base)
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub enum Import {
    Func {
        namespace: String,
        name: String,
        params: Vec<WasmType>,
        result: Vec<WasmType>,
    },
    Global {
        namespace: String,
        name: String,
        var_type: WasmType,
    },
}

impl Import {
    pub fn format_key(ns: &str, name: &str) -> (String, String) {
        (ns.to_string(), name.to_string())
    }

    /// Get the key used to look this import up in the Interface's import hashmap
    pub fn get_key(&self) -> (String, String) {
        match self {
            Import::Func {
                namespace, name, ..
            } => Self::format_key(&namespace, &name),
            Import::Global {
                namespace, name, ..
            } => Self::format_key(&namespace, &name),
        }
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub enum Export {
    Func {
        name: String,
        params: Vec<WasmType>,
        result: Vec<WasmType>,
    },
    Global {
        name: String,
        var_type: WasmType,
    },
}

impl Export {
    pub fn format_key(name: &str) -> String {
        name.to_string()
    }

    /// Get the key used to look this export up in the Interface's export hashmap
    pub fn get_key(&self) -> String {
        match self {
            Export::Func { name, .. } => Self::format_key(&name),
            Export::Global { name, .. } => Self::format_key(&name),
        }
    }
}

/// Primitive wasm type
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum WasmType {
    I32,
    I64,
    F32,
    F64,
}

impl std::fmt::Display for WasmType {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        write!(
            f,
            "{}",
            match self {
                WasmType::I32 => "i32",
                WasmType::I64 => "i64",
                WasmType::F32 => "f32",
                WasmType::F64 => "f64",
            }
        )
    }
}

#[cfg(test)]
mod test {
    use crate::parser;

    #[test]
    fn merging_works() {
        let interface1_src = r#"(assert_import (func "env" "plus_one" (param i32) (result i32)))"#;
        let interface2_src = r#"(assert_import (func "env" "plus_one" (param i64) (result i64)))"#;
        let interface3_src = r#"(assert_import (func "env" "times_two" (param i64) (result i64)))"#;
        let interface4_src =
            r#"(assert_import (func "env" "times_two" (param i64 i64) (result i64)))"#;
        let interface5_src = r#"(assert_export (func "empty_bank_account" (param) (result)))"#;
        let interface6_src = r#"(assert_export (func "empty_bank_account" (param) (result i64)))"#;

        let interface1 = parser::parse_interface(interface1_src).unwrap();
        let interface2 = parser::parse_interface(interface2_src).unwrap();
        let interface3 = parser::parse_interface(interface3_src).unwrap();
        let interface4 = parser::parse_interface(interface4_src).unwrap();
        let interface5 = parser::parse_interface(interface5_src).unwrap();
        let interface6 = parser::parse_interface(interface6_src).unwrap();

        assert!(interface1.merge(interface2.clone()).is_err());
        assert!(interface2.merge(interface1.clone()).is_err());
        assert!(interface1.merge(interface3.clone()).is_ok());
        assert!(interface2.merge(interface3.clone()).is_ok());
        assert!(interface3.merge(interface2.clone()).is_ok());
        assert!(
            interface1.merge(interface1.clone()).is_ok(),
            "exact matches are accepted"
        );
        assert!(interface3.merge(interface4.clone()).is_err());
        assert!(interface5.merge(interface5.clone()).is_ok());
        assert!(interface5.merge(interface6.clone()).is_err());
    }
}