tauri_codegen/
lib.rs

1// Copyright 2019-2024 Tauri Programme within The Commons Conservancy
2// SPDX-License-Identifier: Apache-2.0
3// SPDX-License-Identifier: MIT
4
5//! - Embed, hash, and compress assets, including icons for the app as well as the tray icon.
6//! - Parse `tauri.conf.json` at compile time and generate the Config struct.
7
8#![doc(
9  html_logo_url = "https://github.com/tauri-apps/tauri/raw/dev/.github/icon.png",
10  html_favicon_url = "https://github.com/tauri-apps/tauri/raw/dev/.github/icon.png"
11)]
12
13pub use self::context::{ContextData, context_codegen};
14use crate::embedded_assets::{EmbeddedAssetsError, ensure_out_dir};
15use proc_macro2::TokenStream;
16use quote::{ToTokens, TokenStreamExt, quote};
17use std::{
18  borrow::Cow,
19  fmt::{self, Write},
20  path::{Path, PathBuf},
21};
22pub use tauri_utils::config::{Config, parse::ConfigError};
23use tauri_utils::platform::Target;
24use tauri_utils::write_if_changed;
25
26mod context;
27pub mod embedded_assets;
28pub mod image;
29#[doc(hidden)]
30pub mod vendor;
31
32/// Represents all the errors that can happen while reading the config during codegen.
33#[derive(Debug, thiserror::Error)]
34#[non_exhaustive]
35pub enum CodegenConfigError {
36  #[error("unable to access current working directory: {0}")]
37  CurrentDir(std::io::Error),
38
39  // this error should be "impossible" because we use std::env::current_dir() - cover it anyways
40  #[error(
41    "Tauri config file has no parent, this shouldn't be possible. file an issue on https://github.com/tauri-apps/tauri - target {0}"
42  )]
43  Parent(PathBuf),
44
45  #[error("unable to parse inline JSON TAURI_CONFIG env var: {0}")]
46  FormatInline(serde_json::Error),
47
48  #[error(transparent)]
49  Json(#[from] serde_json::Error),
50
51  #[error("{0}")]
52  ConfigError(#[from] ConfigError),
53}
54
55/// Get the [`Config`] from the `TAURI_CONFIG` environmental variable, or read from the passed path.
56///
57/// If the passed path is relative, it should be relative to the current working directory of the
58/// compiling crate.
59pub fn get_config(path: &Path) -> Result<(Config, PathBuf), CodegenConfigError> {
60  let path = if path.is_relative() {
61    let cwd = std::env::current_dir().map_err(CodegenConfigError::CurrentDir)?;
62    Cow::Owned(cwd.join(path))
63  } else {
64    Cow::Borrowed(path)
65  };
66
67  // this should be impossible because of the use of `current_dir()` above, but handle it anyways
68  let parent = path
69    .parent()
70    .map(ToOwned::to_owned)
71    .ok_or_else(|| CodegenConfigError::Parent(path.into_owned()))?;
72
73  let target = std::env::var("TAURI_ENV_TARGET_TRIPLE")
74    .as_deref()
75    .map(Target::from_triple)
76    .unwrap_or_else(|_| Target::current());
77
78  // in the future we may want to find a way to not need the TAURI_CONFIG env var so that
79  // it is impossible for the content of two separate configs to get mixed up. The chances are
80  // already unlikely unless the developer goes out of their way to run the cli on a different
81  // project than the target crate.
82  let mut config =
83    serde_json::from_value(tauri_utils::config::parse::read_from(target, &parent)?.0)?;
84
85  if let Ok(env) = std::env::var("TAURI_CONFIG") {
86    let merge_config: serde_json::Value =
87      serde_json::from_str(&env).map_err(CodegenConfigError::FormatInline)?;
88    json_patch::merge(&mut config, &merge_config);
89  }
90
91  // Set working directory to where `tauri.config.json` is, so that relative paths in it are parsed correctly.
92  let old_cwd = std::env::current_dir().map_err(CodegenConfigError::CurrentDir)?;
93  std::env::set_current_dir(parent.clone()).map_err(CodegenConfigError::CurrentDir)?;
94
95  let config = serde_json::from_value(config)?;
96
97  // Reset working directory.
98  std::env::set_current_dir(old_cwd).map_err(CodegenConfigError::CurrentDir)?;
99
100  Ok((config, parent))
101}
102
103/// Create a blake3 checksum of the passed bytes.
104fn checksum(bytes: &[u8]) -> Result<String, fmt::Error> {
105  let mut hasher = vendor::blake3_reference::Hasher::default();
106  hasher.update(bytes);
107
108  let mut bytes = [0u8; 32];
109  hasher.finalize(&mut bytes);
110
111  let mut hex = String::with_capacity(2 * bytes.len());
112  for b in bytes {
113    write!(hex, "{b:02x}")?;
114  }
115  Ok(hex)
116}
117
118/// Cache the data to `$OUT_DIR`, only if it does not already exist.
119///
120/// Due to using a checksum as the filename, an existing file should be the exact same content
121/// as the data being checked.
122struct Cached {
123  checksum: String,
124}
125
126impl TryFrom<String> for Cached {
127  type Error = EmbeddedAssetsError;
128
129  fn try_from(value: String) -> Result<Self, Self::Error> {
130    Self::try_from(Vec::from(value))
131  }
132}
133
134impl TryFrom<Vec<u8>> for Cached {
135  type Error = EmbeddedAssetsError;
136
137  fn try_from(content: Vec<u8>) -> Result<Self, Self::Error> {
138    let checksum = checksum(content.as_ref()).map_err(EmbeddedAssetsError::Hex)?;
139    let path = ensure_out_dir()?.join(&checksum);
140
141    write_if_changed(&path, &content)
142      .map(|_| Self { checksum })
143      .map_err(|error| EmbeddedAssetsError::AssetWrite { path, error })
144  }
145}
146
147impl ToTokens for Cached {
148  fn to_tokens(&self, tokens: &mut TokenStream) {
149    let path = &self.checksum;
150    tokens.append_all(quote!(::std::concat!(::std::env!("OUT_DIR"), "/", #path)))
151  }
152}
tauri_codegen/lib.rs

tauri_codegen/
lib.rs
