Struct FunctionType

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pub struct FunctionType { /* private fields */ }

Expand description

Function signature type.

Implementations§

Source §

impl FunctionType

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pub fn new(params: Vec<ValueType>, return_type: Option<ValueType>) -> Self

New function type given the signature in-params(params) and return type (return_type)

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pub fn form(&self) -> u8

Function form (currently only valid value is 0x60)

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pub fn params(&self) -> &[ValueType]

Parameters in the function signature.

Examples found in repository ?

examples/exports.rs (line 77)

44fn main() {
45
46    // Example executable takes one argument which must
47    // refernce the existing file with a valid wasm module
48    let args: Vec<_> = args().collect();
49    if args.len() < 2 {
50        println!("Prints export function names with and their types");
51        println!("Usage: {} <wasm file>", args[0]);
52        return;
53    }
54
55    // Here we load module using dedicated for this purpose
56    // `deserialize_file` function (which works only with modules)
57    let module = sophon_wasm::deserialize_file(&args[1]).expect("File to be deserialized");
58
59    // Query the export section from the loaded module. Note that not every
60    // wasm module obliged to contain export section. So in case there is no
61    // any export section, we panic with the corresponding error.
62    let export_section = module.export_section().expect("No export section found");
63
64    // Process all exports, leaving only those which reference the internal function
65    // of the wasm module
66    let exports: Vec<String> = export_section.entries().iter()
67        .filter_map(|entry|
68            // This is match on export variant, which can be function, global,table or memory
69            // We are interested only in functions for an example
70            match *entry.internal() {
71                // Return function export name (return by field() function and it's index)
72                Internal::Function(index) => Some((entry.field(), index as usize)),
73                _ => None
74            })
75        // Another map to resolve function signature index given it's internal index and return
76        // the printable string of the export
77        .map(|(field, index)| format!("{:}: {:?}", field, type_by_index(&module, index).params())).collect();
78
79    // Print the result
80    for export in exports {
81        println!("{:}", export);
82    }
83}

More examples

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examples/invoke.rs (line 66)

9fn main() {
10    let args: Vec<_> = args().collect();
11    if args.len() < 3 {
12        println!("Usage: {} <wasm file> <exported func> [<arg>...]", args[0]);
13        return;
14    }
15    let func_name = &args[2];
16    let (_, program_args) = args.split_at(3);
17
18    // Intrepreter initialization.
19    let program = sophon_wasm::ProgramInstance::new();
20
21    let module = sophon_wasm::deserialize_file(&args[1]).expect("File to be deserialized");
22
23    // Extracts call arguments from command-line arguments
24    let execution_params = {
25        // Export section has an entry with a func_name with an index inside a module
26        let export_section = module.export_section().expect("No export section found");
27        // It's a section with function declarations (which are references to the type section entries)
28        let function_section = module.function_section().expect("No function section found");
29        // Type section stores function types which are referenced by function_section entries
30        let type_section = module.type_section().expect("No type section found");
31
32        // Given function name used to find export section entry which contains
33        // an `internal` field which points to the index in the function index space
34        let found_entry = export_section.entries().iter()
35            .find(|entry| func_name == entry.field()).expect(&format!("No export with name {} found", func_name));
36
37        // Function index in the function index space (internally-defined + imported)
38        let function_index: usize = match found_entry.internal() {
39            &Internal::Function(index) => index as usize,
40            _ => panic!("Founded export is not a function"),
41        };
42
43        // We need to count import section entries (functions only!) to subtract it from function_index
44        // and obtain the index within the function section
45        let import_section_len: usize = match module.import_section() {
46            Some(import) =>
47                import.entries().iter().filter(|entry| match entry.external() {
48                    &External::Function(_) => true,
49                    _ => false,
50                    }).count(),
51            None => 0,
52        };
53
54        // Calculates a function index within module's function section
55        let function_index_in_section = function_index - import_section_len;
56
57        // Getting a type reference from a function section entry
58        let func_type_ref: usize = function_section.entries()[function_index_in_section].type_ref() as usize;
59
60        // Use the reference to get an actual function type
61        let function_type: &FunctionType = match &type_section.types()[func_type_ref] {
62            &Type::Function(ref func_type) => func_type,
63        };
64
65        // Parses arguments and constructs runtime values in correspondence of their types
66        let args: Vec<RuntimeValue> = function_type.params().iter().enumerate().map(|(i, value)| match value {
67            &ValueType::I32 => RuntimeValue::I32(program_args[i].parse::<i32>().expect(&format!("Can't parse arg #{} as i32", program_args[i]))),
68            &ValueType::I64 => RuntimeValue::I64(program_args[i].parse::<i64>().expect(&format!("Can't parse arg #{} as i64", program_args[i]))),
69            &ValueType::F32 => RuntimeValue::F32(program_args[i].parse::<f32>().expect(&format!("Can't parse arg #{} as f32", program_args[i]))),
70            &ValueType::F64 => RuntimeValue::F64(program_args[i].parse::<f64>().expect(&format!("Can't parse arg #{} as f64", program_args[i]))),
71        }).collect();
72
73        interpreter::ExecutionParams::from(args)
74    };
75
76    // Intialize deserialized module. It adds module into It expects 3 parameters:
77    // - a name for the module
78    // - a module declaration
79    // - "main" module doesn't import native module(s) this is why we don't need to provide external native modules here
80    // This test shows how to implement native module https://github.com/NikVolf/sophon-wasm/blob/master/src/interpreter/tests/basics.rs#L197
81    let module = program.add_module("main", module, None).expect("Failed to initialize module");
82
83    println!("Result: {:?}", module.execute_export(func_name, execution_params).expect(""));
84}