1 files changed, 458 insertions, 0 deletions
diff --git a/cli/source_maps.rs b/cli/source_maps.rs
new file mode 100644
index 000000000..95df48a31
--- /dev/null
+++ b/cli/source_maps.rs
@@ -0,0 +1,458 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+//! This mod provides functions to remap a deno::V8Exception based on a source map
+use deno::StackFrame;
+use deno::V8Exception;
+use serde_json;
+use source_map_mappings::parse_mappings;
+use source_map_mappings::Bias;
+use source_map_mappings::Mappings;
+use std::collections::HashMap;
+use std::str;
+
+pub trait SourceMapGetter {
+  /// Returns the raw source map file.
+  fn get_source_map(&self, script_name: &str) -> Option<Vec<u8>>;
+  fn get_source_line(&self, script_name: &str, line: usize) -> Option<String>;
+}
+
+/// Cached filename lookups. The key can be None if a previous lookup failed to
+/// find a SourceMap.
+pub type CachedMaps = HashMap<String, Option<SourceMap>>;
+
+pub struct SourceMap {
+  mappings: Mappings,
+  sources: Vec<String>,
+}
+
+impl SourceMap {
+  /// Take a JSON string and attempt to decode it, returning an optional
+  /// instance of `SourceMap`.
+  fn from_json(json_str: &str) -> Option<Self> {
+    // Ugly. Maybe use serde_derive.
+    match serde_json::from_str::<serde_json::Value>(json_str) {
+      Ok(serde_json::Value::Object(map)) => match map["mappings"].as_str() {
+        None => None,
+        Some(mappings_str) => {
+          match parse_mappings::<()>(mappings_str.as_bytes()) {
+            Err(_) => None,
+            Ok(mappings) => {
+              if !map["sources"].is_array() {
+                return None;
+              }
+              let sources_val = map["sources"].as_array().unwrap();
+              let mut sources = Vec::<String>::new();
+
+              for source_val in sources_val {
+                match source_val.as_str() {
+                  None => return None,
+                  Some(source) => {
+                    sources.push(source.to_string());
+                  }
+                }
+              }
+
+              Some(SourceMap { sources, mappings })
+            }
+          }
+        }
+      },
+      _ => None,
+    }
+  }
+}
+
+// The bundle does not get built for 'cargo check', so we don't embed the
+// bundle source map.  The built in source map is the source map for the main
+// JavaScript bundle which is then used to create the snapshot.  Runtime stack
+// traces can contain positions within the bundle which we will map to the
+// original Deno TypeScript code.
+#[cfg(feature = "check-only")]
+fn builtin_source_map(_: &str) -> Option<Vec<u8>> {
+  None
+}
+
+#[cfg(not(feature = "check-only"))]
+fn builtin_source_map(script_name: &str) -> Option<Vec<u8>> {
+  if script_name.ends_with("CLI_SNAPSHOT.js") {
+    Some(crate::js::CLI_SNAPSHOT_MAP.to_vec())
+  } else if script_name.ends_with("COMPILER_SNAPSHOT.js") {
+    Some(crate::js::COMPILER_SNAPSHOT_MAP.to_vec())
+  } else {
+    None
+  }
+}
+
+/// Apply a source map to a V8Exception, returning a V8Exception where the filenames,
+/// the lines and the columns point to their original source location, not their
+/// transpiled location if applicable.
+pub fn apply_source_map<G: SourceMapGetter>(
+  v8_exception: &V8Exception,
+  getter: &G,
+) -> V8Exception {
+  let mut mappings_map: CachedMaps = HashMap::new();
+
+  let mut frames = Vec::<StackFrame>::new();
+  for frame in &v8_exception.frames {
+    let f = frame_apply_source_map(&frame, &mut mappings_map, getter);
+    frames.push(f);
+  }
+
+  let (script_resource_name, line_number, start_column) =
+    get_maybe_orig_position(
+      v8_exception.script_resource_name.clone(),
+      v8_exception.line_number,
+      v8_exception.start_column,
+      &mut mappings_map,
+      getter,
+    );
+  // It is better to just move end_column to be the same distance away from
+  // start column because sometimes the code point is not available in the
+  // source file map.
+  let end_column = match v8_exception.end_column {
+    Some(ec) => {
+      if let Some(sc) = start_column {
+        Some(ec - (v8_exception.start_column.unwrap() - sc))
+      } else {
+        None
+      }
+    }
+    _ => None,
+  };
+  // if there is a source line that we might be different in the source file, we
+  // will go fetch it from the getter
+  let source_line = match line_number {
+    Some(ln)
+      if v8_exception.source_line.is_some()
+        && script_resource_name.is_some() =>
+    {
+      getter.get_source_line(
+        &v8_exception.script_resource_name.clone().unwrap(),
+        ln as usize,
+      )
+    }
+    _ => v8_exception.source_line.clone(),
+  };
+
+  V8Exception {
+    message: v8_exception.message.clone(),
+    frames,
+    error_level: v8_exception.error_level,
+    source_line,
+    script_resource_name,
+    line_number,
+    start_column,
+    end_column,
+    // These are difficult to map to their original position and they are not
+    // currently used in any output, so we don't remap them.
+    start_position: v8_exception.start_position,
+    end_position: v8_exception.end_position,
+  }
+}
+
+fn frame_apply_source_map<G: SourceMapGetter>(
+  frame: &StackFrame,
+  mappings_map: &mut CachedMaps,
+  getter: &G,
+) -> StackFrame {
+  let (script_name, line, column) = get_orig_position(
+    frame.script_name.to_string(),
+    frame.line,
+    frame.column,
+    mappings_map,
+    getter,
+  );
+
+  StackFrame {
+    script_name,
+    function_name: frame.function_name.clone(),
+    line,
+    column,
+    is_eval: frame.is_eval,
+    is_constructor: frame.is_constructor,
+    is_wasm: frame.is_wasm,
+  }
+}
+
+fn get_maybe_orig_position<G: SourceMapGetter>(
+  script_name: Option<String>,
+  line: Option<i64>,
+  column: Option<i64>,
+  mappings_map: &mut CachedMaps,
+  getter: &G,
+) -> (Option<String>, Option<i64>, Option<i64>) {
+  match (script_name, line, column) {
+    (Some(script_name_v), Some(line_v), Some(column_v)) => {
+      let (script_name, line, column) = get_orig_position(
+        script_name_v,
+        line_v - 1,
+        column_v,
+        mappings_map,
+        getter,
+      );
+      (Some(script_name), Some(line), Some(column))
+    }
+    _ => (None, None, None),
+  }
+}
+
+pub fn get_orig_position<G: SourceMapGetter>(
+  script_name: String,
+  line: i64,
+  column: i64,
+  mappings_map: &mut CachedMaps,
+  getter: &G,
+) -> (String, i64, i64) {
+  let maybe_sm = get_mappings(&script_name, mappings_map, getter);
+  let default_pos = (script_name, line, column);
+
+  match maybe_sm {
+    None => default_pos,
+    Some(sm) => match sm.mappings.original_location_for(
+      line as u32,
+      column as u32,
+      Bias::default(),
+    ) {
+      None => default_pos,
+      Some(mapping) => match &mapping.original {
+        None => default_pos,
+        Some(original) => {
+          let orig_source = sm.sources[original.source as usize].clone();
+          (
+            orig_source,
+            i64::from(original.original_line),
+            i64::from(original.original_column),
+          )
+        }
+      },
+    },
+  }
+}
+
+fn get_mappings<'a, G: SourceMapGetter>(
+  script_name: &str,
+  mappings_map: &'a mut CachedMaps,
+  getter: &G,
+) -> &'a Option<SourceMap> {
+  mappings_map
+    .entry(script_name.to_string())
+    .or_insert_with(|| parse_map_string(script_name, getter))
+}
+
+// TODO(kitsonk) parsed source maps should probably be cached in state in
+// the module meta data.
+fn parse_map_string<G: SourceMapGetter>(
+  script_name: &str,
+  getter: &G,
+) -> Option<SourceMap> {
+  builtin_source_map(script_name)
+    .or_else(|| getter.get_source_map(script_name))
+    .and_then(|raw_source_map| {
+      SourceMap::from_json(str::from_utf8(&raw_source_map).unwrap())
+    })
+}
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+
+  struct MockSourceMapGetter {}
+
+  impl SourceMapGetter for MockSourceMapGetter {
+    fn get_source_map(&self, script_name: &str) -> Option<Vec<u8>> {
+      let s = match script_name {
+        "foo_bar.ts" => r#"{"sources": ["foo_bar.ts"], "mappings":";;;IAIA,OAAO,CAAC,GAAG,CAAC,qBAAqB,EAAE,EAAE,CAAC,OAAO,CAAC,CAAC;IAC/C,OAAO,CAAC,GAAG,CAAC,eAAe,EAAE,IAAI,CAAC,QAAQ,CAAC,IAAI,CAAC,CAAC;IACjD,OAAO,CAAC,GAAG,CAAC,WAAW,EAAE,IAAI,CAAC,QAAQ,CAAC,EAAE,CAAC,CAAC;IAE3C,OAAO,CAAC,GAAG,CAAC,GAAG,CAAC,CAAC"}"#,
+        "bar_baz.ts" => r#"{"sources": ["bar_baz.ts"], "mappings":";;;IAEA,CAAC,KAAK,IAAI,EAAE;QACV,MAAM,GAAG,GAAG,sDAAa,OAAO,2BAAC,CAAC;QAClC,OAAO,CAAC,GAAG,CAAC,GAAG,CAAC,CAAC;IACnB,CAAC,CAAC,EAAE,CAAC;IAEQ,QAAA,GAAG,GAAG,KAAK,CAAC;IAEzB,OAAO,CAAC,GAAG,CAAC,GAAG,CAAC,CAAC"}"#,
+        _ => return None,
+      };
+      Some(s.as_bytes().to_owned())
+    }
+
+    fn get_source_line(
+      &self,
+      script_name: &str,
+      line: usize,
+    ) -> Option<String> {
+      let s = match script_name {
+        "foo_bar.ts" => vec![
+          "console.log('foo');",
+          "console.log('foo');",
+          "console.log('foo');",
+          "console.log('foo');",
+          "console.log('foo');",
+        ],
+        _ => return None,
+      };
+      if s.len() > line {
+        Some(s[line].to_string())
+      } else {
+        None
+      }
+    }
+  }
+
+  fn error1() -> V8Exception {
+    V8Exception {
+      message: "Error: foo bar".to_string(),
+      source_line: None,
+      script_resource_name: None,
+      line_number: None,
+      start_position: None,
+      end_position: None,
+      error_level: None,
+      start_column: None,
+      end_column: None,
+      frames: vec![
+        StackFrame {
+          line: 4,
+          column: 16,
+          script_name: "foo_bar.ts".to_string(),
+          function_name: "foo".to_string(),
+          is_eval: false,
+          is_constructor: false,
+          is_wasm: false,
+        },
+        StackFrame {
+          line: 5,
+          column: 20,
+          script_name: "bar_baz.ts".to_string(),
+          function_name: "qat".to_string(),
+          is_eval: false,
+          is_constructor: false,
+          is_wasm: false,
+        },
+        StackFrame {
+          line: 1,
+          column: 1,
+          script_name: "deno_main.js".to_string(),
+          function_name: "".to_string(),
+          is_eval: false,
+          is_constructor: false,
+          is_wasm: false,
+        },
+      ],
+    }
+  }
+
+  #[test]
+  fn v8_exception_apply_source_map_1() {
+    let e = error1();
+    let getter = MockSourceMapGetter {};
+    let actual = apply_source_map(&e, &getter);
+    let expected = V8Exception {
+      message: "Error: foo bar".to_string(),
+      source_line: None,
+      script_resource_name: None,
+      line_number: None,
+      start_position: None,
+      end_position: None,
+      error_level: None,
+      start_column: None,
+      end_column: None,
+      frames: vec![
+        StackFrame {
+          line: 5,
+          column: 12,
+          script_name: "foo_bar.ts".to_string(),
+          function_name: "foo".to_string(),
+          is_eval: false,
+          is_constructor: false,
+          is_wasm: false,
+        },
+        StackFrame {
+          line: 4,
+          column: 14,
+          script_name: "bar_baz.ts".to_string(),
+          function_name: "qat".to_string(),
+          is_eval: false,
+          is_constructor: false,
+          is_wasm: false,
+        },
+        StackFrame {
+          line: 1,
+          column: 1,
+          script_name: "deno_main.js".to_string(),
+          function_name: "".to_string(),
+          is_eval: false,
+          is_constructor: false,
+          is_wasm: false,
+        },
+      ],
+    };
+    assert_eq!(actual, expected);
+  }
+
+  #[test]
+  fn v8_exception_apply_source_map_2() {
+    let e = V8Exception {
+      message: "TypeError: baz".to_string(),
+      source_line: None,
+      script_resource_name: None,
+      line_number: None,
+      start_position: None,
+      end_position: None,
+      error_level: None,
+      start_column: None,
+      end_column: None,
+      frames: vec![StackFrame {
+        line: 11,
+        column: 12,
+        script_name: "CLI_SNAPSHOT.js".to_string(),
+        function_name: "setLogDebug".to_string(),
+        is_eval: false,
+        is_constructor: false,
+        is_wasm: false,
+      }],
+    };
+    let getter = MockSourceMapGetter {};
+    let actual = apply_source_map(&e, &getter);
+    assert_eq!(actual.message, "TypeError: baz");
+    // Because this is accessing the live bundle, this test might be more fragile
+    assert_eq!(actual.frames.len(), 1);
+    assert!(actual.frames[0].script_name.ends_with("/window.ts"));
+  }
+
+  #[test]
+  fn v8_exception_apply_source_map_line() {
+    let e = V8Exception {
+      message: "TypeError: baz".to_string(),
+      source_line: Some("foo".to_string()),
+      script_resource_name: Some("foo_bar.ts".to_string()),
+      line_number: Some(4),
+      start_position: None,
+      end_position: None,
+      error_level: None,
+      start_column: Some(16),
+      end_column: None,
+      frames: vec![],
+    };
+    let getter = MockSourceMapGetter {};
+    let actual = apply_source_map(&e, &getter);
+    assert_eq!(actual.source_line, Some("console.log('foo');".to_string()));
+  }
+
+  #[test]
+  fn source_map_from_json() {
+    let json = r#"{"version":3,"file":"error_001.js","sourceRoot":"","sources":["file:///Users/rld/src/deno/tests/error_001.ts"],"names":[],"mappings":"AAAA,SAAS,GAAG;IACV,MAAM,KAAK,CAAC,KAAK,CAAC,CAAC;AACrB,CAAC;AAED,SAAS,GAAG;IACV,GAAG,EAAE,CAAC;AACR,CAAC;AAED,GAAG,EAAE,CAAC"}"#;
+    let sm = SourceMap::from_json(json).unwrap();
+    assert_eq!(sm.sources.len(), 1);
+    assert_eq!(
+      sm.sources[0],
+      "file:///Users/rld/src/deno/tests/error_001.ts"
+    );
+    let mapping = sm
+      .mappings
+      .original_location_for(1, 10, Bias::default())
+      .unwrap();
+    assert_eq!(mapping.generated_line, 1);
+    assert_eq!(mapping.generated_column, 10);
+    assert_eq!(
+      mapping.original,
+      Some(source_map_mappings::OriginalLocation {
+        source: 0,
+        original_line: 1,
+        original_column: 8,
+        name: None
+      })
+    );
+  }
+}