refactor(repl): factor out ReplEditor and ReplSession (#13131)

1 files changed, 382 insertions, 0 deletions

diff --git a/cli/tools/repl/editor.rs b/cli/tools/repl/editor.rs
new file mode 100644
index 000000000..f61e53d3f
--- /dev/null
+++ b/cli/tools/repl/editor.rs
@@ -0,0 +1,382 @@
+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+
+use crate::colors;
+use deno_ast::swc::parser::error::SyntaxError;
+use deno_ast::swc::parser::token::Token;
+use deno_ast::swc::parser::token::Word;
+use deno_core::error::AnyError;
+use deno_core::parking_lot::Mutex;
+use deno_core::serde_json::json;
+use deno_core::serde_json::Value;
+use rustyline::completion::Completer;
+use rustyline::error::ReadlineError;
+use rustyline::highlight::Highlighter;
+use rustyline::validate::ValidationContext;
+use rustyline::validate::ValidationResult;
+use rustyline::validate::Validator;
+use rustyline::CompletionType;
+use rustyline::Config;
+use rustyline::Context;
+use rustyline::Editor;
+use rustyline_derive::{Helper, Hinter};
+use std::borrow::Cow;
+use std::path::PathBuf;
+use std::sync::Arc;
+
+use super::channel::RustylineSyncMessageSender;
+
+// Provides helpers to the editor like validation for multi-line edits, completion candidates for
+// tab completion.
+#[derive(Helper, Hinter)]
+pub struct EditorHelper {
+  pub context_id: u64,
+  pub sync_sender: RustylineSyncMessageSender,
+}
+
+impl EditorHelper {
+  pub fn get_global_lexical_scope_names(&self) -> Vec<String> {
+    let evaluate_response = self
+      .sync_sender
+      .post_message(
+        "Runtime.globalLexicalScopeNames",
+        Some(json!({
+          "executionContextId": self.context_id,
+        })),
+      )
+      .unwrap();
+
+    evaluate_response
+      .get("names")
+      .unwrap()
+      .as_array()
+      .unwrap()
+      .iter()
+      .map(|n| n.as_str().unwrap().to_string())
+      .collect()
+  }
+
+  pub fn get_expression_property_names(&self, expr: &str) -> Vec<String> {
+    // try to get the properties from the expression
+    if let Some(properties) = self.get_object_expr_properties(expr) {
+      return properties;
+    }
+
+    // otherwise fall back to the prototype
+    let expr_type = self.get_expression_type(expr);
+    let object_expr = match expr_type.as_deref() {
+      // possibilities: https://chromedevtools.github.io/devtools-protocol/v8/Runtime/#type-RemoteObject
+      Some("object") => "Object.prototype",
+      Some("function") => "Function.prototype",
+      Some("string") => "String.prototype",
+      Some("boolean") => "Boolean.prototype",
+      Some("bigint") => "BigInt.prototype",
+      Some("number") => "Number.prototype",
+      _ => return Vec::new(), // undefined, symbol, and unhandled
+    };
+
+    self
+      .get_object_expr_properties(object_expr)
+      .unwrap_or_else(Vec::new)
+  }
+
+  fn get_expression_type(&self, expr: &str) -> Option<String> {
+    self
+      .evaluate_expression(expr)?
+      .get("result")?
+      .get("type")?
+      .as_str()
+      .map(|s| s.to_string())
+  }
+
+  fn get_object_expr_properties(
+    &self,
+    object_expr: &str,
+  ) -> Option<Vec<String>> {
+    let evaluate_result = self.evaluate_expression(object_expr)?;
+    let object_id = evaluate_result.get("result")?.get("objectId")?;
+
+    let get_properties_response = self
+      .sync_sender
+      .post_message(
+        "Runtime.getProperties",
+        Some(json!({
+          "objectId": object_id,
+        })),
+      )
+      .ok()?;
+
+    Some(
+      get_properties_response
+        .get("result")?
+        .as_array()
+        .unwrap()
+        .iter()
+        .map(|r| r.get("name").unwrap().as_str().unwrap().to_string())
+        .collect(),
+    )
+  }
+
+  fn evaluate_expression(&self, expr: &str) -> Option<Value> {
+    let evaluate_response = self
+      .sync_sender
+      .post_message(
+        "Runtime.evaluate",
+        Some(json!({
+          "contextId": self.context_id,
+          "expression": expr,
+          "throwOnSideEffect": true,
+          "timeout": 200,
+        })),
+      )
+      .ok()?;
+
+    if evaluate_response.get("exceptionDetails").is_some() {
+      None
+    } else {
+      Some(evaluate_response)
+    }
+  }
+}
+
+fn is_word_boundary(c: char) -> bool {
+  if c == '.' {
+    false
+  } else {
+    char::is_ascii_whitespace(&c) || char::is_ascii_punctuation(&c)
+  }
+}
+
+fn get_expr_from_line_at_pos(line: &str, cursor_pos: usize) -> &str {
+  let start = line[..cursor_pos]
+    .rfind(is_word_boundary)
+    .map_or_else(|| 0, |i| i);
+  let end = line[cursor_pos..]
+    .rfind(is_word_boundary)
+    .map_or_else(|| cursor_pos, |i| cursor_pos + i);
+
+  let word = &line[start..end];
+  let word = word.strip_prefix(is_word_boundary).unwrap_or(word);
+  let word = word.strip_suffix(is_word_boundary).unwrap_or(word);
+
+  word
+}
+
+impl Completer for EditorHelper {
+  type Candidate = String;
+
+  fn complete(
+    &self,
+    line: &str,
+    pos: usize,
+    _ctx: &Context<'_>,
+  ) -> Result<(usize, Vec<String>), ReadlineError> {
+    let lsp_completions = self.sync_sender.lsp_completions(line, pos);
+    if !lsp_completions.is_empty() {
+      // assumes all lsp completions have the same start position
+      return Ok((
+        lsp_completions[0].span.lo.0 as usize,
+        lsp_completions.into_iter().map(|c| c.new_text).collect(),
+      ));
+    }
+
+    let expr = get_expr_from_line_at_pos(line, pos);
+
+    // check if the expression is in the form `obj.prop`
+    if let Some(index) = expr.rfind('.') {
+      let sub_expr = &expr[..index];
+      let prop_name = &expr[index + 1..];
+      let candidates = self
+        .get_expression_property_names(sub_expr)
+        .into_iter()
+        .filter(|n| !n.starts_with("Symbol(") && n.starts_with(prop_name))
+        .collect();
+
+      Ok((pos - prop_name.len(), candidates))
+    } else {
+      // combine results of declarations and globalThis properties
+      let mut candidates = self
+        .get_expression_property_names("globalThis")
+        .into_iter()
+        .chain(self.get_global_lexical_scope_names())
+        .filter(|n| n.starts_with(expr))
+        .collect::<Vec<_>>();
+
+      // sort and remove duplicates
+      candidates.sort();
+      candidates.dedup(); // make sure to sort first
+
+      Ok((pos - expr.len(), candidates))
+    }
+  }
+}
+
+impl Validator for EditorHelper {
+  fn validate(
+    &self,
+    ctx: &mut ValidationContext,
+  ) -> Result<ValidationResult, ReadlineError> {
+    let mut stack: Vec<Token> = Vec::new();
+    let mut in_template = false;
+
+    for item in deno_ast::lex(ctx.input(), deno_ast::MediaType::TypeScript) {
+      if let deno_ast::TokenOrComment::Token(token) = item.inner {
+        match token {
+          Token::BackQuote => in_template = !in_template,
+          Token::LParen
+          | Token::LBracket
+          | Token::LBrace
+          | Token::DollarLBrace => stack.push(token),
+          Token::RParen | Token::RBracket | Token::RBrace => {
+            match (stack.pop(), token) {
+              (Some(Token::LParen), Token::RParen)
+              | (Some(Token::LBracket), Token::RBracket)
+              | (Some(Token::LBrace), Token::RBrace)
+              | (Some(Token::DollarLBrace), Token::RBrace) => {}
+              (Some(left), _) => {
+                return Ok(ValidationResult::Invalid(Some(format!(
+                  "Mismatched pairs: {:?} is not properly closed",
+                  left
+                ))))
+              }
+              (None, _) => {
+                // While technically invalid when unpaired, it should be V8's task to output error instead.
+                // Thus marked as valid with no info.
+                return Ok(ValidationResult::Valid(None));
+              }
+            }
+          }
+          Token::Error(error) => {
+            match error.kind() {
+              // If there is unterminated template, it continues to read input.
+              SyntaxError::UnterminatedTpl => {}
+              _ => {
+                // If it failed parsing, it should be V8's task to output error instead.
+                // Thus marked as valid with no info.
+                return Ok(ValidationResult::Valid(None));
+              }
+            }
+          }
+          _ => {}
+        }
+      }
+    }
+
+    if !stack.is_empty() || in_template {
+      return Ok(ValidationResult::Incomplete);
+    }
+
+    Ok(ValidationResult::Valid(None))
+  }
+}
+
+impl Highlighter for EditorHelper {
+  fn highlight_hint<'h>(&self, hint: &'h str) -> Cow<'h, str> {
+    hint.into()
+  }
+
+  fn highlight_candidate<'c>(
+    &self,
+    candidate: &'c str,
+    completion: rustyline::CompletionType,
+  ) -> Cow<'c, str> {
+    if completion == CompletionType::List {
+      candidate.into()
+    } else {
+      self.highlight(candidate, 0)
+    }
+  }
+
+  fn highlight_char(&self, line: &str, _: usize) -> bool {
+    !line.is_empty()
+  }
+
+  fn highlight<'l>(&self, line: &'l str, _: usize) -> Cow<'l, str> {
+    let mut out_line = String::from(line);
+
+    for item in deno_ast::lex(line, deno_ast::MediaType::TypeScript) {
+      // Adding color adds more bytes to the string,
+      // so an offset is needed to stop spans falling out of sync.
+      let offset = out_line.len() - line.len();
+      let span = std::ops::Range {
+        start: item.span.lo.0 as usize,
+        end: item.span.hi.0 as usize,
+      };
+
+      out_line.replace_range(
+        span.start + offset..span.end + offset,
+        &match item.inner {
+          deno_ast::TokenOrComment::Token(token) => match token {
+            Token::Str { .. } | Token::Template { .. } | Token::BackQuote => {
+              colors::green(&line[span]).to_string()
+            }
+            Token::Regex(_, _) => colors::red(&line[span]).to_string(),
+            Token::Num(_) | Token::BigInt(_) => {
+              colors::yellow(&line[span]).to_string()
+            }
+            Token::Word(word) => match word {
+              Word::True | Word::False | Word::Null => {
+                colors::yellow(&line[span]).to_string()
+              }
+              Word::Keyword(_) => colors::cyan(&line[span]).to_string(),
+              Word::Ident(ident) => {
+                if ident == *"undefined" {
+                  colors::gray(&line[span]).to_string()
+                } else if ident == *"Infinity" || ident == *"NaN" {
+                  colors::yellow(&line[span]).to_string()
+                } else if ident == *"async" || ident == *"of" {
+                  colors::cyan(&line[span]).to_string()
+                } else {
+                  line[span].to_string()
+                }
+              }
+            },
+            _ => line[span].to_string(),
+          },
+          deno_ast::TokenOrComment::Comment { .. } => {
+            colors::gray(&line[span]).to_string()
+          }
+        },
+      );
+    }
+
+    out_line.into()
+  }
+}
+
+#[derive(Clone)]
+pub struct ReplEditor {
+  inner: Arc<Mutex<Editor<EditorHelper>>>,
+  history_file_path: PathBuf,
+}
+
+impl ReplEditor {
+  pub fn new(helper: EditorHelper, history_file_path: PathBuf) -> Self {
+    let editor_config = Config::builder()
+      .completion_type(CompletionType::List)
+      .build();
+
+    let mut editor = Editor::with_config(editor_config);
+    editor.set_helper(Some(helper));
+    editor.load_history(&history_file_path).unwrap_or(());
+
+    ReplEditor {
+      inner: Arc::new(Mutex::new(editor)),
+      history_file_path,
+    }
+  }
+
+  pub fn readline(&self) -> Result<String, ReadlineError> {
+    self.inner.lock().readline("> ")
+  }
+
+  pub fn add_history_entry(&self, entry: String) {
+    self.inner.lock().add_history_entry(entry);
+  }
+
+  pub fn save_history(&self) -> Result<(), AnyError> {
+    std::fs::create_dir_all(self.history_file_path.parent().unwrap())?;
+
+    self.inner.lock().save_history(&self.history_file_path)?;
+    Ok(())
+  }
+}