tidy up deno_core modules (#5923)

1 files changed, 412 insertions, 0 deletions

diff --git a/core/errors.rs b/core/errors.rs
new file mode 100644
index 000000000..bc821b266
--- /dev/null
+++ b/core/errors.rs
@@ -0,0 +1,412 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+use rusty_v8 as v8;
+use std::any::Any;
+use std::any::TypeId;
+use std::convert::TryFrom;
+use std::convert::TryInto;
+use std::error::Error;
+use std::fmt;
+use std::ops::Deref;
+
+// The Send and Sync traits are required because deno is multithreaded and we
+// need to be able to handle errors across threads.
+pub trait AnyError: Any + Error + Send + Sync + 'static {}
+impl<T> AnyError for T where T: Any + Error + Send + Sync + Sized + 'static {}
+
+#[derive(Debug)]
+pub struct ErrBox(Box<dyn AnyError>);
+
+impl dyn AnyError {
+  pub fn downcast_ref<T: AnyError>(&self) -> Option<&T> {
+    if Any::type_id(self) == TypeId::of::<T>() {
+      let target = self as *const Self as *const T;
+      let target = unsafe { &*target };
+      Some(target)
+    } else {
+      None
+    }
+  }
+}
+
+impl ErrBox {
+  pub fn downcast<T: AnyError>(self) -> Result<T, Self> {
+    if Any::type_id(&*self.0) == TypeId::of::<T>() {
+      let target = Box::into_raw(self.0) as *mut T;
+      let target = unsafe { Box::from_raw(target) };
+      Ok(*target)
+    } else {
+      Err(self)
+    }
+  }
+}
+
+impl AsRef<dyn AnyError> for ErrBox {
+  fn as_ref(&self) -> &dyn AnyError {
+    self.0.as_ref()
+  }
+}
+
+impl Deref for ErrBox {
+  type Target = Box<dyn AnyError>;
+  fn deref(&self) -> &Self::Target {
+    &self.0
+  }
+}
+
+impl<T: AnyError> From<T> for ErrBox {
+  fn from(error: T) -> Self {
+    Self(Box::new(error))
+  }
+}
+
+impl From<Box<dyn AnyError>> for ErrBox {
+  fn from(boxed: Box<dyn AnyError>) -> Self {
+    Self(boxed)
+  }
+}
+
+impl fmt::Display for ErrBox {
+  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    self.0.fmt(f)
+  }
+}
+
+/// A `JSError` represents an exception coming from V8, with stack frames and
+/// line numbers. The deno_cli crate defines another `JSError` type, which wraps
+/// the one defined here, that adds source map support and colorful formatting.
+#[derive(Debug, PartialEq, Clone)]
+pub struct JSError {
+  pub message: String,
+  pub source_line: Option<String>,
+  pub script_resource_name: Option<String>,
+  pub line_number: Option<i64>,
+  pub start_column: Option<i64>, // 0-based
+  pub end_column: Option<i64>,   // 0-based
+  pub frames: Vec<JSStackFrame>,
+  pub formatted_frames: Vec<String>,
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub struct JSStackFrame {
+  pub type_name: Option<String>,
+  pub function_name: Option<String>,
+  pub method_name: Option<String>,
+  pub file_name: Option<String>,
+  pub line_number: Option<i64>,
+  pub column_number: Option<i64>,
+  pub eval_origin: Option<String>,
+  pub is_top_level: Option<bool>,
+  pub is_eval: bool,
+  pub is_native: bool,
+  pub is_constructor: bool,
+  pub is_async: bool,
+  pub is_promise_all: bool,
+  pub promise_index: Option<i64>,
+}
+
+fn get_property<'a>(
+  scope: &mut impl v8::ToLocal<'a>,
+  context: v8::Local<v8::Context>,
+  object: v8::Local<v8::Object>,
+  key: &str,
+) -> Option<v8::Local<'a, v8::Value>> {
+  let key = v8::String::new(scope, key).unwrap();
+  object.get(scope, context, key.into())
+}
+
+impl JSError {
+  pub(crate) fn create(js_error: Self) -> ErrBox {
+    ErrBox::from(js_error)
+  }
+
+  pub fn from_v8_exception(
+    scope: &mut impl v8::InIsolate,
+    exception: v8::Local<v8::Value>,
+  ) -> Self {
+    // Create a new HandleScope because we're creating a lot of new local
+    // handles below.
+    let mut hs = v8::HandleScope::new(scope);
+    let scope = hs.enter();
+    let context = { scope.get_current_context().unwrap() };
+
+    let msg = v8::Exception::create_message(scope, exception);
+
+    let (message, frames, formatted_frames) = if exception.is_native_error() {
+      // The exception is a JS Error object.
+      let exception: v8::Local<v8::Object> =
+        exception.clone().try_into().unwrap();
+
+      // Get the message by formatting error.name and error.message.
+      let name = get_property(scope, context, exception, "name")
+        .and_then(|m| m.to_string(scope))
+        .map(|s| s.to_rust_string_lossy(scope))
+        .unwrap_or_else(|| "undefined".to_string());
+      let message_prop = get_property(scope, context, exception, "message")
+        .and_then(|m| m.to_string(scope))
+        .map(|s| s.to_rust_string_lossy(scope))
+        .unwrap_or_else(|| "undefined".to_string());
+      let message = format!("Uncaught {}: {}", name, message_prop);
+
+      // Access error.stack to ensure that prepareStackTrace() has been called.
+      // This should populate error.__callSiteEvals and error.__formattedFrames.
+      let _ = get_property(scope, context, exception, "stack");
+
+      // Read an array of structured frames from error.__callSiteEvals.
+      let frames_v8 =
+        get_property(scope, context, exception, "__callSiteEvals");
+      let frames_v8: Option<v8::Local<v8::Array>> =
+        frames_v8.and_then(|a| a.try_into().ok());
+
+      // Read an array of pre-formatted frames from error.__formattedFrames.
+      let formatted_frames_v8 =
+        get_property(scope, context, exception, "__formattedFrames");
+      let formatted_frames_v8: Option<v8::Local<v8::Array>> =
+        formatted_frames_v8.and_then(|a| a.try_into().ok());
+
+      // Convert them into Vec<JSStack> and Vec<String> respectively.
+      let mut frames: Vec<JSStackFrame> = vec![];
+      let mut formatted_frames: Vec<String> = vec![];
+      if let (Some(frames_v8), Some(formatted_frames_v8)) =
+        (frames_v8, formatted_frames_v8)
+      {
+        for i in 0..frames_v8.length() {
+          let call_site: v8::Local<v8::Object> = frames_v8
+            .get_index(scope, context, i)
+            .unwrap()
+            .try_into()
+            .unwrap();
+          let type_name: Option<v8::Local<v8::String>> =
+            get_property(scope, context, call_site, "typeName")
+              .unwrap()
+              .try_into()
+              .ok();
+          let type_name = type_name.map(|s| s.to_rust_string_lossy(scope));
+          let function_name: Option<v8::Local<v8::String>> =
+            get_property(scope, context, call_site, "functionName")
+              .unwrap()
+              .try_into()
+              .ok();
+          let function_name =
+            function_name.map(|s| s.to_rust_string_lossy(scope));
+          let method_name: Option<v8::Local<v8::String>> =
+            get_property(scope, context, call_site, "methodName")
+              .unwrap()
+              .try_into()
+              .ok();
+          let method_name = method_name.map(|s| s.to_rust_string_lossy(scope));
+          let file_name: Option<v8::Local<v8::String>> =
+            get_property(scope, context, call_site, "fileName")
+              .unwrap()
+              .try_into()
+              .ok();
+          let file_name = file_name.map(|s| s.to_rust_string_lossy(scope));
+          let line_number: Option<v8::Local<v8::Integer>> =
+            get_property(scope, context, call_site, "lineNumber")
+              .unwrap()
+              .try_into()
+              .ok();
+          let line_number = line_number.map(|n| n.value());
+          let column_number: Option<v8::Local<v8::Integer>> =
+            get_property(scope, context, call_site, "columnNumber")
+              .unwrap()
+              .try_into()
+              .ok();
+          let column_number = column_number.map(|n| n.value());
+          let eval_origin: Option<v8::Local<v8::String>> =
+            get_property(scope, context, call_site, "evalOrigin")
+              .unwrap()
+              .try_into()
+              .ok();
+          let eval_origin = eval_origin.map(|s| s.to_rust_string_lossy(scope));
+          let is_top_level: Option<v8::Local<v8::Boolean>> =
+            get_property(scope, context, call_site, "isTopLevel")
+              .unwrap()
+              .try_into()
+              .ok();
+          let is_top_level = is_top_level.map(|b| b.is_true());
+          let is_eval: v8::Local<v8::Boolean> =
+            get_property(scope, context, call_site, "isEval")
+              .unwrap()
+              .try_into()
+              .unwrap();
+          let is_eval = is_eval.is_true();
+          let is_native: v8::Local<v8::Boolean> =
+            get_property(scope, context, call_site, "isNative")
+              .unwrap()
+              .try_into()
+              .unwrap();
+          let is_native = is_native.is_true();
+          let is_constructor: v8::Local<v8::Boolean> =
+            get_property(scope, context, call_site, "isConstructor")
+              .unwrap()
+              .try_into()
+              .unwrap();
+          let is_constructor = is_constructor.is_true();
+          let is_async: v8::Local<v8::Boolean> =
+            get_property(scope, context, call_site, "isAsync")
+              .unwrap()
+              .try_into()
+              .unwrap();
+          let is_async = is_async.is_true();
+          let is_promise_all: v8::Local<v8::Boolean> =
+            get_property(scope, context, call_site, "isPromiseAll")
+              .unwrap()
+              .try_into()
+              .unwrap();
+          let is_promise_all = is_promise_all.is_true();
+          let promise_index: Option<v8::Local<v8::Integer>> =
+            get_property(scope, context, call_site, "columnNumber")
+              .unwrap()
+              .try_into()
+              .ok();
+          let promise_index = promise_index.map(|n| n.value());
+          frames.push(JSStackFrame {
+            type_name,
+            function_name,
+            method_name,
+            file_name,
+            line_number,
+            column_number,
+            eval_origin,
+            is_top_level,
+            is_eval,
+            is_native,
+            is_constructor,
+            is_async,
+            is_promise_all,
+            promise_index,
+          });
+          let formatted_frame: v8::Local<v8::String> = formatted_frames_v8
+            .get_index(scope, context, i)
+            .unwrap()
+            .try_into()
+            .unwrap();
+          let formatted_frame = formatted_frame.to_rust_string_lossy(scope);
+          formatted_frames.push(formatted_frame)
+        }
+      }
+      (message, frames, formatted_frames)
+    } else {
+      // The exception is not a JS Error object.
+      // Get the message given by V8::Exception::create_message(), and provide
+      // empty frames.
+      (msg.get(scope).to_rust_string_lossy(scope), vec![], vec![])
+    };
+
+    Self {
+      message,
+      script_resource_name: msg
+        .get_script_resource_name(scope)
+        .and_then(|v| v8::Local::<v8::String>::try_from(v).ok())
+        .map(|v| v.to_rust_string_lossy(scope)),
+      source_line: msg
+        .get_source_line(scope, context)
+        .map(|v| v.to_rust_string_lossy(scope)),
+      line_number: msg.get_line_number(context).and_then(|v| v.try_into().ok()),
+      start_column: msg.get_start_column().try_into().ok(),
+      end_column: msg.get_end_column().try_into().ok(),
+      frames,
+      formatted_frames,
+    }
+  }
+}
+
+impl Error for JSError {}
+
+fn format_source_loc(
+  file_name: &str,
+  line_number: i64,
+  column_number: i64,
+) -> String {
+  let line_number = line_number;
+  let column_number = column_number;
+  format!("{}:{}:{}", file_name, line_number, column_number)
+}
+
+impl fmt::Display for JSError {
+  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    if let Some(script_resource_name) = &self.script_resource_name {
+      if self.line_number.is_some() && self.start_column.is_some() {
+        assert!(self.line_number.is_some());
+        assert!(self.start_column.is_some());
+        let source_loc = format_source_loc(
+          script_resource_name,
+          self.line_number.unwrap(),
+          self.start_column.unwrap(),
+        );
+        write!(f, "{}", source_loc)?;
+      }
+      if self.source_line.is_some() {
+        let source_line = self.source_line.as_ref().unwrap();
+        write!(f, "\n{}\n", source_line)?;
+        let mut s = String::new();
+        for i in 0..self.end_column.unwrap() {
+          if i >= self.start_column.unwrap() {
+            s.push('^');
+          } else if source_line.chars().nth(i as usize).unwrap() == '\t' {
+            s.push('\t');
+          } else {
+            s.push(' ');
+          }
+        }
+        writeln!(f, "{}", s)?;
+      }
+    }
+
+    write!(f, "{}", self.message)?;
+
+    for formatted_frame in &self.formatted_frames {
+      // TODO: Strip ANSI color from formatted_frame.
+      write!(f, "\n    at {}", formatted_frame)?;
+    }
+    Ok(())
+  }
+}
+
+pub(crate) fn attach_handle_to_error(
+  scope: &mut impl v8::InIsolate,
+  err: ErrBox,
+  handle: v8::Local<v8::Value>,
+) -> ErrBox {
+  ErrWithV8Handle::new(scope, err, handle).into()
+}
+
+// TODO(piscisaureus): rusty_v8 should implement the Error trait on
+// values of type v8::Global<T>.
+pub struct ErrWithV8Handle {
+  err: ErrBox,
+  handle: v8::Global<v8::Value>,
+}
+
+impl ErrWithV8Handle {
+  pub fn new(
+    scope: &mut impl v8::InIsolate,
+    err: ErrBox,
+    handle: v8::Local<v8::Value>,
+  ) -> Self {
+    let handle = v8::Global::new_from(scope, handle);
+    Self { err, handle }
+  }
+
+  pub fn get_handle(&self) -> &v8::Global<v8::Value> {
+    &self.handle
+  }
+}
+
+unsafe impl Send for ErrWithV8Handle {}
+unsafe impl Sync for ErrWithV8Handle {}
+
+impl Error for ErrWithV8Handle {}
+
+impl fmt::Display for ErrWithV8Handle {
+  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    self.err.fmt(f)
+  }
+}
+
+impl fmt::Debug for ErrWithV8Handle {
+  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    self.err.fmt(f)
+  }
+}