v-common-v8 0.1.30

// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.

use rusty_v8 as v8;
use std::borrow::Cow;
use std::convert::TryFrom;
use std::convert::TryInto;
use std::error::Error;
use std::fmt;
use std::fmt::Debug;
use std::fmt::Display;
use std::fmt::Formatter;
use std::io;

/// A generic wrapper that can encapsulate any concrete error type.
pub type AnyError = anyhow::Error;

/// Creates a new error with a caller-specified error class name and message.
pub fn custom_error(class: &'static str, message: impl Into<Cow<'static, str>>) -> AnyError {
    CustomError {
        class,
        message: message.into(),
    }
    .into()
}

pub fn generic_error(message: impl Into<Cow<'static, str>>) -> AnyError {
    custom_error("Error", message)
}

pub fn type_error(message: impl Into<Cow<'static, str>>) -> AnyError {
    custom_error("TypeError", message)
}

pub fn uri_error(message: impl Into<Cow<'static, str>>) -> AnyError {
    custom_error("URIError", message)
}

pub fn last_os_error() -> AnyError {
    io::Error::last_os_error().into()
}

pub fn bad_resource(message: impl Into<Cow<'static, str>>) -> AnyError {
    custom_error("BadResource", message)
}

pub fn bad_resource_id() -> AnyError {
    custom_error("BadResource", "Bad resource ID")
}

pub fn not_supported() -> AnyError {
    custom_error("NotSupported", "The operation is not supported")
}

pub fn resource_unavailable() -> AnyError {
    custom_error("Busy", "Resource is unavailable because it is in use by a promise")
}

/// A simple error type that lets the creator specify both the error message and
/// the error class name. This type is private; externally it only ever appears
/// wrapped in an `AnyError`. To retrieve the error class name from a wrapped
/// `CustomError`, use the function `get_custom_error_class()`.
#[derive(Debug)]
struct CustomError {
    class: &'static str,
    message: Cow<'static, str>,
}

impl Display for CustomError {
    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
        f.write_str(&self.message)
    }
}

impl Error for CustomError {}

/// If this error was crated with `custom_error()`, return the specified error
/// class name. In all other cases this function returns `None`.
pub fn get_custom_error_class(error: &AnyError) -> Option<&'static str> {
    error.downcast_ref::<CustomError>().map(|e| e.class)
}

/// 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 stack: Option<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>,
}

impl JsStackFrame {
    pub fn from_location(file_name: Option<String>, line_number: Option<i64>, column_number: Option<i64>) -> Self {
        Self {
            type_name: None,
            function_name: None,
            method_name: None,
            file_name,
            line_number,
            column_number,
            eval_origin: None,
            is_top_level: None,
            is_eval: false,
            is_native: false,
            is_constructor: false,
            is_async: false,
            is_promise_all: false,
            promise_index: None,
        }
    }
}

fn get_property<'a>(scope: &mut v8::HandleScope<'a>, object: v8::Local<v8::Object>, key: &str) -> Option<v8::Local<'a, v8::Value>> {
    let key = v8::String::new(scope, key).unwrap();
    object.get(scope, key.into())
}

impl JsError {
    pub fn create(js_error: Self) -> AnyError {
        js_error.into()
    }

    pub fn from_v8_exception(scope: &mut v8::HandleScope, exception: v8::Local<v8::Value>) -> Self {
        // Create a new HandleScope because we're creating a lot of new local
        // handles below.
        let scope = &mut v8::HandleScope::new(scope);

        let msg = v8::Exception::create_message(scope, exception);

        let (message, frames, stack) = 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, exception, "name")
                .filter(|v| !v.is_undefined())
                .and_then(|m| m.to_string(scope))
                .map(|s| s.to_rust_string_lossy(scope))
                .unwrap_or_else(|| "Error".to_string());
            let message_prop = get_property(scope, exception, "message")
                .filter(|v| !v.is_undefined())
                .and_then(|m| m.to_string(scope))
                .map(|s| s.to_rust_string_lossy(scope))
                .unwrap_or_else(|| "".to_string());
            let message = if name != "" && message_prop != "" {
                format!("Uncaught {}: {}", name, message_prop)
            } else if name != "" {
                format!("Uncaught {}", name)
            } else if message_prop != "" {
                format!("Uncaught {}", message_prop)
            } else {
                "Uncaught".to_string()
            };

            // Access error.stack to ensure that prepareStackTrace() has been called.
            // This should populate error.__callSiteEvals.
            let stack: Option<v8::Local<v8::String>> = get_property(scope, exception, "stack").unwrap().try_into().ok();
            let stack = stack.map(|s| s.to_rust_string_lossy(scope));

            // FIXME(bartlmieju): the rest of this function is CLI only

            // Read an array of structured frames from error.__callSiteEvals.
            let frames_v8 = get_property(scope, exception, "__callSiteEvals");
            let frames_v8: Option<v8::Local<v8::Array>> = frames_v8.and_then(|a| a.try_into().ok());

            // Convert them into Vec<JSStack> and Vec<String> respectively.
            let mut frames: Vec<JsStackFrame> = vec![];
            if let Some(frames_v8) = frames_v8 {
                for i in 0..frames_v8.length() {
                    let call_site: v8::Local<v8::Object> = frames_v8.get_index(scope, i).unwrap().try_into().unwrap();
                    let type_name: Option<v8::Local<v8::String>> = get_property(scope, 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, 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, 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, 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, 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, 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, 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, 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, call_site, "isEval").unwrap().try_into().unwrap();
                    let is_eval = is_eval.is_true();
                    let is_native: v8::Local<v8::Boolean> = get_property(scope, call_site, "isNative").unwrap().try_into().unwrap();
                    let is_native = is_native.is_true();
                    let is_constructor: v8::Local<v8::Boolean> = get_property(scope, call_site, "isConstructor").unwrap().try_into().unwrap();
                    let is_constructor = is_constructor.is_true();
                    let is_async: v8::Local<v8::Boolean> = get_property(scope, 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, 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, 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,
                    });
                }
            }
            (message, frames, stack)
        } 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![], None)
        };

        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).map(|v| v.to_rust_string_lossy(scope)),
            line_number: msg.get_line_number(scope).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,
            stack,
        }
    }
}

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 Display for JsError {
    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
        if let Some(stack) = &self.stack {
            let stack_lines = stack.lines();
            if stack_lines.count() > 1 {
                return writeln!(f, "{}", stack);
            }
        }

        writeln!(f, "{}", self.message)?;
        if let Some(script_resource_name) = &self.script_resource_name {
            if self.line_number.is_some() && self.start_column.is_some() {
                let source_loc = format_source_loc(script_resource_name, self.line_number.unwrap(), self.start_column.unwrap());
                writeln!(f, "    at {}", source_loc)?;
            }
        }
        Ok(())
    }
}

pub fn attach_handle_to_error(scope: &mut v8::Isolate, err: AnyError, handle: v8::Local<v8::Value>) -> AnyError {
    // TODO(bartomieju): this is a special case...
    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: AnyError,
    handle: v8::Global<v8::Value>,
}

impl ErrWithV8Handle {
    pub fn new(scope: &mut v8::Isolate, err: AnyError, handle: v8::Local<v8::Value>) -> Self {
        let handle = v8::Global::new(scope, handle);
        Self {
            err,
            handle,
        }
    }

    pub fn get_handle<'s>(&self, scope: &mut v8::HandleScope<'s>) -> v8::Local<'s, v8::Value> {
        v8::Local::new(scope, &self.handle)
    }
}

unsafe impl Send for ErrWithV8Handle {}
unsafe impl Sync for ErrWithV8Handle {}

impl Error for ErrWithV8Handle {}

impl Display for ErrWithV8Handle {
    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
        <AnyError as Display>::fmt(&self.err, f)
    }
}

impl Debug for ErrWithV8Handle {
    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
        <Self as Display>::fmt(self, f)
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_bad_resource() {
        let err = bad_resource("Resource has been closed");
        assert_eq!(err.to_string(), "Resource has been closed");
    }

    #[test]
    fn test_bad_resource_id() {
        let err = bad_resource_id();
        assert_eq!(err.to_string(), "Bad resource ID");
    }
}