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

use crate::OpFn;
use crate::OpState;
use anyhow::Error;

pub type SourcePair = (&'static str, Box<SourceLoadFn>);
pub type SourceLoadFn = dyn Fn() -> Result<String, Error>;
pub type OpPair = (&'static str, Box<OpFn>);
pub type OpMiddlewareFn = dyn Fn(&'static str, Box<OpFn>) -> Box<OpFn>;
pub type OpStateFn = dyn Fn(&mut OpState) -> Result<(), Error>;

#[derive(Default)]
pub struct Extension {
  js_files: Option<Vec<SourcePair>>,
  ops: Option<Vec<OpPair>>,
  opstate_fn: Option<Box<OpStateFn>>,
  middleware_fn: Option<Box<OpMiddlewareFn>>,
  initialized: bool,
}

// Note: this used to be a trait, but we "downgraded" it to a single concrete type
// for the initial iteration, it will likely become a trait in the future
impl Extension {
  pub fn builder() -> ExtensionBuilder {
    Default::default()
  }

  /// returns JS source code to be loaded into the isolate (either at snapshotting,
  /// or at startup).  as a vector of a tuple of the file name, and the source code.
  pub fn init_js(&self) -> &[SourcePair] {
    match &self.js_files {
      Some(files) => files,
      None => &[],
    }
  }

  /// Called at JsRuntime startup to initialize ops in the isolate.
  pub fn init_ops(&mut self) -> Option<Vec<OpPair>> {
    // TODO(@AaronO): maybe make op registration idempotent
    if self.initialized {
      panic!("init_ops called twice: not idempotent or correct");
    }
    self.initialized = true;

    self.ops.take()
  }

  /// Allows setting up the initial op-state of an isolate at startup.
  pub fn init_state(&self, state: &mut OpState) -> Result<(), Error> {
    match &self.opstate_fn {
      Some(ofn) => ofn(state),
      None => Ok(()),
    }
  }

  /// init_middleware lets us middleware op registrations, it's called before init_ops
  pub fn init_middleware(&mut self) -> Option<Box<OpMiddlewareFn>> {
    self.middleware_fn.take()
  }
}

// Provides a convenient builder pattern to declare Extensions
#[derive(Default)]
pub struct ExtensionBuilder {
  js: Vec<SourcePair>,
  ops: Vec<OpPair>,
  state: Option<Box<OpStateFn>>,
  middleware: Option<Box<OpMiddlewareFn>>,
}

impl ExtensionBuilder {
  pub fn js(&mut self, js_files: Vec<SourcePair>) -> &mut Self {
    self.js.extend(js_files);
    self
  }

  pub fn ops(&mut self, ops: Vec<OpPair>) -> &mut Self {
    self.ops.extend(ops);
    self
  }

  pub fn state<F>(&mut self, opstate_fn: F) -> &mut Self
  where
    F: Fn(&mut OpState) -> Result<(), Error> + 'static,
  {
    self.state = Some(Box::new(opstate_fn));
    self
  }

  pub fn middleware<F>(&mut self, middleware_fn: F) -> &mut Self
  where
    F: Fn(&'static str, Box<OpFn>) -> Box<OpFn> + 'static,
  {
    self.middleware = Some(Box::new(middleware_fn));
    self
  }

  pub fn build(&mut self) -> Extension {
    let js_files = Some(std::mem::take(&mut self.js));
    let ops = Some(std::mem::take(&mut self.ops));
    Extension {
      js_files,
      ops,
      opstate_fn: self.state.take(),
      middleware_fn: self.middleware.take(),
      initialized: false,
    }
  }
}
/// Helps embed JS files in an extension. Returns Vec<(&'static str, Box<SourceLoadFn>)>
/// representing the filename and source code. This is only meant for extensions
/// that will be snapshotted, as code will be loaded at runtime.
///
/// Example:
/// ```ignore
/// include_js_files!(
///   prefix "deno:extensions/hello",
///   "01_hello.js",
///   "02_goodbye.js",
/// )
/// ```
#[macro_export]
macro_rules! include_js_files {
  (prefix $prefix:literal, $($file:literal,)+) => {
    vec![
      $((
        concat!($prefix, "/", $file),
        Box::new(|| {
          let c = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"));
          let path = c.join($file);
          println!("cargo:rerun-if-changed={}", path.display());
          let src = std::fs::read_to_string(path)?;
          Ok(src)
        }),
      ),)+
    ]
  };
}