tinywasm_cli/
load.rs

1use std::ffi::OsStr;
2use std::io::{Read, Write};
3use std::path::Path;
4
5use eyre::{Context, Result, bail};
6use tinywasm::Module;
7
8#[derive(Clone, Copy, Debug, PartialEq, Eq)]
9pub enum InputFormat {
10    Wasm,
11    Wat,
12    Twasm,
13}
14
15pub struct LoadedModule {
16    pub module: Module,
17    pub format: InputFormat,
18}
19
20pub fn load_module(input: &str) -> Result<LoadedModule> {
21    let bytes = read_input_bytes(input)?;
22    load_module_from_bytes(input, &bytes)
23}
24
25pub fn load_compilable_module(input: &str) -> Result<Module> {
26    let loaded = load_module(input)?;
27    if loaded.format == InputFormat::Twasm {
28        bail!("input is already a twasm archive; use `run`, `dump`, or `inspect` instead")
29    }
30    Ok(loaded.module)
31}
32
33pub fn default_twasm_output_path(input: &str) -> Result<String> {
34    if input == "-" {
35        bail!("--output is required when compiling from stdin")
36    }
37
38    let path = Path::new(input);
39    let stem = path.file_stem().and_then(OsStr::to_str).unwrap_or("module");
40    let output = path.with_file_name(format!("{stem}.twasm"));
41    Ok(output.to_string_lossy().into_owned())
42}
43
44pub fn write_output_bytes(output: &str, bytes: &[u8], force: bool) -> Result<()> {
45    if output == "-" {
46        std::io::stdout().write_all(bytes)?;
47        std::io::stdout().flush()?;
48        return Ok(());
49    }
50
51    let path = Path::new(output);
52    if path.exists() && !force {
53        bail!("output file already exists: {output}; pass --force to overwrite")
54    }
55
56    std::fs::write(path, bytes).with_context(|| format!("failed to write output file `{output}`"))?;
57    Ok(())
58}
59
60fn load_module_from_bytes(input: &str, bytes: &[u8]) -> Result<LoadedModule> {
61    if bytes.starts_with(b"TWAS") {
62        let module = Module::try_from_twasm(bytes).with_context(|| format!("failed to read twasm input `{input}`"))?;
63        return Ok(LoadedModule { module, format: InputFormat::Twasm });
64    }
65
66    #[cfg(feature = "wat")]
67    if input != "-" && has_extension(input, "wat") {
68        let wasm = wat::parse_bytes(bytes).with_context(|| format!("failed to parse WAT input `{input}`"))?;
69        let module =
70            tinywasm::parse_bytes(&wasm).with_context(|| format!("failed to parse Wasm generated from `{input}`"))?;
71        return Ok(LoadedModule { module, format: InputFormat::Wat });
72    }
73
74    #[cfg(not(feature = "wat"))]
75    if input != "-" && has_extension(input, "wat") {
76        bail!("wat support is not enabled in this build")
77    }
78
79    #[cfg(feature = "wat")]
80    if input == "-"
81        && let Ok(wasm) = wat::parse_bytes(bytes)
82    {
83        let module = tinywasm::parse_bytes(&wasm).context("failed to parse Wasm generated from stdin WAT input")?;
84        return Ok(LoadedModule { module, format: InputFormat::Wat });
85    }
86
87    let module = tinywasm::parse_bytes(bytes).with_context(|| format!("failed to parse Wasm input `{input}`"))?;
88    Ok(LoadedModule { module, format: InputFormat::Wasm })
89}
90
91fn read_input_bytes(input: &str) -> Result<Vec<u8>> {
92    if input == "-" {
93        let mut bytes = Vec::new();
94        std::io::stdin().read_to_end(&mut bytes).context("failed to read stdin")?;
95        return Ok(bytes);
96    }
97
98    std::fs::read(input).with_context(|| format!("failed to read input `{input}`"))
99}
100
101fn has_extension(path: &str, extension: &str) -> bool {
102    Path::new(path).extension().and_then(OsStr::to_str) == Some(extension)
103}
tinywasm_cli/load.rs

tinywasm_cli/
load.rs
