tauri/core/tauri-codegen/src/context.rs

// Copyright 2019-2021 Tauri Programme within The Commons Conservancy
// SPDX-License-Identifier: Apache-2.0
// SPDX-License-Identifier: MIT

use std::ffi::OsStr;
use std::path::{Path, PathBuf};

use proc_macro2::TokenStream;
use quote::quote;
use sha2::{Digest, Sha256};

use tauri_utils::assets::AssetKey;
use tauri_utils::config::{AppUrl, Config, PatternKind, WindowUrl};
use tauri_utils::html::{inject_nonce_token, parse as parse_html, NodeRef};

#[cfg(feature = "shell-scope")]
use tauri_utils::config::{ShellAllowedArg, ShellAllowedArgs, ShellAllowlistScope};

use crate::embedded_assets::{AssetOptions, CspHashes, EmbeddedAssets, EmbeddedAssetsError};

/// Necessary data needed by [`context_codegen`] to generate code for a Tauri application context.
pub struct ContextData {
  pub dev: bool,
  pub config: Config,
  pub config_parent: PathBuf,
  pub root: TokenStream,
}

fn load_csp(document: &mut NodeRef, key: &AssetKey, csp_hashes: &mut CspHashes) {
  #[cfg(target_os = "linux")]
  ::tauri_utils::html::inject_csp_token(document);
  inject_nonce_token(document);
  if let Ok(inline_script_elements) = document.select("script:not(empty)") {
    let mut scripts = Vec::new();
    for inline_script_el in inline_script_elements {
      let script = inline_script_el.as_node().text_contents();
      let mut hasher = Sha256::new();
      hasher.update(&script);
      let hash = hasher.finalize();
      scripts.push(format!("'sha256-{}'", base64::encode(&hash)));
    }
    csp_hashes
      .inline_scripts
      .entry(key.clone().into())
      .or_default()
      .append(&mut scripts);
  }
}

fn map_core_assets(
  options: &AssetOptions,
) -> impl Fn(&AssetKey, &Path, &mut Vec<u8>, &mut CspHashes) -> Result<(), EmbeddedAssetsError> {
  #[cfg(feature = "isolation")]
  let pattern = tauri_utils::html::PatternObject::from(&options.pattern);
  let csp = options.csp;
  move |key, path, input, csp_hashes| {
    if path.extension() == Some(OsStr::new("html")) {
      let mut document = parse_html(String::from_utf8_lossy(input).into_owned());

      if csp {
        load_csp(&mut document, key, csp_hashes);

        #[cfg(feature = "isolation")]
        if let tauri_utils::html::PatternObject::Isolation { .. } = &pattern {
          // create the csp for the isolation iframe styling now, to make the runtime less complex
          let mut hasher = Sha256::new();
          hasher.update(tauri_utils::pattern::isolation::IFRAME_STYLE);
          let hash = hasher.finalize();
          csp_hashes
            .styles
            .push(format!("'sha256-{}'", base64::encode(&hash)));
        }
      }

      *input = document.to_string().as_bytes().to_vec();
    }
    Ok(())
  }
}

#[cfg(feature = "isolation")]
fn map_isolation(
  _options: &AssetOptions,
  dir: PathBuf,
) -> impl Fn(&AssetKey, &Path, &mut Vec<u8>, &mut CspHashes) -> Result<(), EmbeddedAssetsError> {
  move |_key, path, input, _csp_hashes| {
    if path.extension() == Some(OsStr::new("html")) {
      let mut isolation_html =
        tauri_utils::html::parse(String::from_utf8_lossy(input).into_owned());

      // this is appended, so no need to reverse order it
      tauri_utils::html::inject_codegen_isolation_script(&mut isolation_html);

      // temporary workaround for windows not loading assets
      tauri_utils::html::inline_isolation(&mut isolation_html, &dir);

      *input = isolation_html.to_string().as_bytes().to_vec()
    }

    Ok(())
  }
}

/// Build a `tauri::Context` for including in application code.
pub fn context_codegen(data: ContextData) -> Result<TokenStream, EmbeddedAssetsError> {
  let ContextData {
    dev,
    config,
    config_parent,
    root,
  } = data;

  let mut options = AssetOptions::new(config.tauri.pattern.clone())
    .freeze_prototype(config.tauri.security.freeze_prototype);
  let csp = if dev {
    config
      .tauri
      .security
      .dev_csp
      .clone()
      .or_else(|| config.tauri.security.csp.clone())
  } else {
    config.tauri.security.csp.clone()
  };
  if csp.is_some() {
    options = options.with_csp();
  }

  let app_url = if dev {
    &config.build.dev_path
  } else {
    &config.build.dist_dir
  };

  let assets = match app_url {
    AppUrl::Url(url) => match url {
      WindowUrl::External(_) => Default::default(),
      WindowUrl::App(path) => {
        if path.components().count() == 0 {
          panic!(
            "The `{}` configuration cannot be empty",
            if dev { "devPath" } else { "distDir" }
          )
        }
        let assets_path = config_parent.join(path);
        if !assets_path.exists() {
          panic!(
            "The `{}` configuration is set to `{:?}` but this path doesn't exist",
            if dev { "devPath" } else { "distDir" },
            path
          )
        }
        EmbeddedAssets::new(assets_path, map_core_assets(&options))?
      }
      _ => unimplemented!(),
    },
    AppUrl::Files(files) => EmbeddedAssets::new(
      files
        .iter()
        .map(|p| config_parent.join(p))
        .collect::<Vec<_>>(),
      map_core_assets(&options),
    )?,
    _ => unimplemented!(),
  };

  // handle default window icons for Windows targets
  let default_window_icon = if cfg!(windows) {
    let icon_path = find_icon(
      &config,
      &config_parent,
      |i| i.ends_with(".ico"),
      "icons/icon.ico",
    );
    quote!(Some(include_bytes!(#icon_path).to_vec()))
  } else if cfg!(target_os = "linux") {
    let icon_path = find_icon(
      &config,
      &config_parent,
      |i| i.ends_with(".png"),
      "icons/icon.png",
    );
    quote!(Some(include_bytes!(#icon_path).to_vec()))
  } else {
    quote!(None)
  };

  let package_name = if let Some(product_name) = &config.package.product_name {
    quote!(#product_name.to_string())
  } else {
    quote!(env!("CARGO_PKG_NAME").to_string())
  };
  let package_version = if let Some(version) = &config.package.version {
    quote!(#version.to_string())
  } else {
    quote!(env!("CARGO_PKG_VERSION").to_string())
  };
  let package_info = quote!(
    #root::PackageInfo {
      name: #package_name,
      version: #package_version,
      authors: env!("CARGO_PKG_AUTHORS"),
      description: env!("CARGO_PKG_DESCRIPTION"),
    }
  );

  #[cfg(target_os = "linux")]
  let system_tray_icon = if let Some(tray) = &config.tauri.system_tray {
    let mut system_tray_icon_path = tray.icon_path.clone();
    system_tray_icon_path.set_extension("png");
    if dev {
      let system_tray_icon_path = config_parent
        .join(system_tray_icon_path)
        .display()
        .to_string();
      quote!(Some(#root::Icon::File(::std::path::PathBuf::from(#system_tray_icon_path))))
    } else {
      let system_tray_icon_file_path = system_tray_icon_path.to_string_lossy().to_string();
      quote!(
        Some(
          #root::Icon::File(
            #root::api::path::resolve_path(
              &#config,
              &#package_info,
              &Default::default(),
              #system_tray_icon_file_path,
              Some(#root::api::path::BaseDirectory::Resource)
            ).expect("failed to resolve resource dir")
          )
        )
      )
    }
  } else {
    quote!(None)
  };

  #[cfg(not(target_os = "linux"))]
  let system_tray_icon = if let Some(tray) = &config.tauri.system_tray {
    let mut system_tray_icon_path = tray.icon_path.clone();
    system_tray_icon_path.set_extension(if cfg!(windows) { "ico" } else { "png" });
    let system_tray_icon_path = config_parent
      .join(system_tray_icon_path)
      .display()
      .to_string();
    quote!(Some(#root::Icon::Raw(include_bytes!(#system_tray_icon_path).to_vec())))
  } else {
    quote!(None)
  };

  #[cfg(target_os = "macos")]
  let info_plist = {
    if dev {
      let info_plist_path = config_parent.join("Info.plist");
      if info_plist_path.exists() {
        let info_plist_path = info_plist_path.display().to_string();
        quote!({
          tauri::embed_plist::embed_info_plist!(#info_plist_path);
        })
      } else {
        quote!(())
      }
    } else {
      quote!(())
    }
  };
  #[cfg(not(target_os = "macos"))]
  let info_plist = quote!(());

  let pattern = match &options.pattern {
    PatternKind::Brownfield => quote!(#root::Pattern::Brownfield(std::marker::PhantomData)),
    #[cfg(feature = "isolation")]
    PatternKind::Isolation { dir } => {
      let dir = config_parent.join(dir);
      if !dir.exists() {
        panic!(
          "The isolation dir configuration is set to `{:?}` but this path doesn't exist",
          dir
        )
      }

      let key = uuid::Uuid::new_v4().to_string();
      let assets = EmbeddedAssets::new(dir.clone(), map_isolation(&options, dir))?;
      let schema = options.isolation_schema;

      quote!(#root::Pattern::Isolation {
        assets: ::std::sync::Arc::new(#assets),
        schema: #schema.into(),
        key: #key.into(),
        crypto_keys: std::boxed::Box::new(::tauri::utils::pattern::isolation::Keys::new().expect("unable to generate cryptographically secure keys for Tauri \"Isolation\" Pattern")),
      })
    }
  };

  #[cfg(feature = "shell-scope")]
  let shell_scope_config = {
    use regex::Regex;
    use tauri_utils::config::ShellAllowlistOpen;

    let shell_scopes = get_allowed_clis(&root, &config.tauri.allowlist.shell.scope);

    let shell_scope_open = match &config.tauri.allowlist.shell.open {
      ShellAllowlistOpen::Flag(false) => quote!(::std::option::Option::None),
      ShellAllowlistOpen::Flag(true) => {
        quote!(::std::option::Option::Some(#root::regex::Regex::new("^https?://").unwrap()))
      }
      ShellAllowlistOpen::Validate(regex) => match Regex::new(regex) {
        Ok(_) => quote!(::std::option::Option::Some(#root::regex::Regex::new(#regex).unwrap())),
        Err(error) => {
          let error = error.to_string();
          quote!({
            compile_error!(#error);
            ::std::option::Option::Some(#root::regex::Regex::new(#regex).unwrap())
          })
        }
      },
      _ => panic!("unknown shell open format, unable to prepare"),
    };

    quote!(#root::ShellScopeConfig {
      open: #shell_scope_open,
      scopes: #shell_scopes
    })
  };

  #[cfg(not(feature = "shell-scope"))]
  let shell_scope_config = quote!();

  Ok(quote!(#root::Context::new(
    #config,
    ::std::sync::Arc::new(#assets),
    #default_window_icon,
    #system_tray_icon,
    #package_info,
    #info_plist,
    #pattern,
    #shell_scope_config
  )))
}

fn find_icon<F: Fn(&&String) -> bool>(
  config: &Config,
  config_parent: &Path,
  predicate: F,
  default: &str,
) -> String {
  let icon_path = config
    .tauri
    .bundle
    .icon
    .iter()
    .find(|i| predicate(i))
    .cloned()
    .unwrap_or_else(|| default.to_string());
  config_parent.join(icon_path).display().to_string()
}

#[cfg(feature = "shell-scope")]
fn get_allowed_clis(root: &TokenStream, scope: &ShellAllowlistScope) -> TokenStream {
  let commands = scope
    .0
    .iter()
    .map(|scope| {
      let sidecar = &scope.sidecar;

      let name = &scope.name;
      let name = quote!(#name.into());

      let command = scope.command.to_string_lossy();
      let command = quote!(::std::path::PathBuf::from(#command));

      let args = match &scope.args {
        ShellAllowedArgs::Flag(true) => quote!(::std::option::Option::None),
        ShellAllowedArgs::Flag(false) => quote!(::std::option::Option::Some(::std::vec![])),
        ShellAllowedArgs::List(list) => {
          let list = list.iter().map(|arg| match arg {
            ShellAllowedArg::Fixed(fixed) => {
              quote!(#root::scope::ShellScopeAllowedArg::Fixed(#fixed.into()))
            }
            ShellAllowedArg::Var { name, validate } => {
              let validate = match validate {
                None => quote!(::std::option::Option::None),
                Some(regex) => match regex::Regex::new(regex) {
                  Ok(regex) => {
                    let regex = regex.as_str();
                    quote!(::std::option::Option::Some(#root::regex::Regex::new(#regex).unwrap()))
                  }
                  Err(error) => {
                    let error = error.to_string();
                    quote!({
                      compile_error!(#error);
                      ::std::option::Option::Some(#root::regex::Regex::new(#regex).unwrap())
                    })
                  }
                },
              };

              quote!(#root::scope::ShellScopeAllowedArg::Var { name: #name.into(), validate: #validate })
            }
            _ => panic!("unknown shell scope arg, unable to prepare"),
          });

          quote!(::std::option::Option::Some(::std::vec![#(#list),*]))
        }
        _ => panic!("unknown shell scope command, unable to prepare"),
      };

      (
        quote!(#name),
        quote!(
          #root::scope::ShellScopeAllowedCommand {
            command: #command,
            args: #args,
            sidecar: #sidecar,
          }
        ),
      )
    })
    .collect::<Vec<_>>();

  if commands.is_empty() {
    quote!(::std::collections::HashMap::new())
  } else {
    let insertions = commands
      .iter()
      .map(|(name, value)| quote!(hashmap.insert(#name, #value);));

    quote!({
      let mut hashmap = ::std::collections::HashMap::new();
      #(#insertions)*
      hashmap
    })
  }
}