[source-map] Convert pasta scopes to 'scopes' proposal scopes

This CL converts pasta function ranges to 'OriginalScope' trees (on top
of the existing 'ScopeTreeEntry's). Follow-up changes will update
name resolving to use 'OriginalScope' and remove the 'ScopeTreeEntry'
type altogether.

The 'SourceMapScopesInfo' class currently has one 'OriginalScope' tree
per original source file. This CL also keeps the 'sourcesList'
consistent with the OriginalScope[] tree list for index maps. This
allows us to use the same index to access both the 'sourcesList' array
as well as retrieve the OriginalScope tree for that original source
file. We may change this in the future into a Map keyed on sourceURL
to be less brittle.

[email protected]

Bug: 389857436
Change-Id: I9ab3821cf6e1d4e0b629921e61fe87c43a9b6d2f
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6189116
Commit-Queue: Simon Zünd <[email protected]>
Reviewed-by: Kim-Anh Tran <[email protected]>

Author: szuend

front_end/core/sdk/SourceMap.ts

@@ -38,7 +38,8 @@ import * as Platform from '../platform/platform.js';
 import * as Root from '../root/root.js';
 
 import type {CallFrame, ScopeChainEntry} from './DebuggerModel.js';
-import {decodeScopes, type Position as GeneratedPosition} from './SourceMapScopes.js';
+import {buildOriginalScopes, type NamedFunctionRange} from './SourceMapFunctionRanges.js';
+import {decodeScopes, type OriginalScope, type Position as GeneratedPosition} from './SourceMapScopes.js';
 import {SourceMapScopesInfo} from './SourceMapScopesInfo.js';
 
 /**
@@ -568,20 +569,29 @@ export class SourceMap {
         const {originalScopes, generatedRanges} = decodeScopes(map, {line: baseLineNumber, column: baseColumnNumber});
         this.#scopesInfo.addOriginalScopes(originalScopes);
         this.#scopesInfo.addGeneratedRanges(generatedRanges);
+      } else if (map.x_com_bloomberg_sourcesFunctionMappings) {
+        const originalScopes = this.parseBloombergScopes(map, baseSourceIndex);
+        this.#scopesInfo.addOriginalScopes(originalScopes);
+      } else {
+        // Keep the OriginalScope[] tree array consistent with sources.
+        this.#scopesInfo.addOriginalScopes(new Array(map.sources.length));
       }
-      this.parseBloombergScopes(map, baseSourceIndex);
     }
   }
 
-  private parseBloombergScopes(map: SourceMapV3Object, baseSourceIndex: number): void {
-    if (!map.x_com_bloomberg_sourcesFunctionMappings) {
-      return;
+  private parseBloombergScopes(map: SourceMapV3Object, baseSourceIndex: number): (OriginalScope|undefined)[] {
+    const scopeList = map.x_com_bloomberg_sourcesFunctionMappings;
+    if (!scopeList) {
+      throw new Error('Cant decode pasta scopes without x_com_bloomberg_sourcesFunctionMappings field');
+    } else if (scopeList.length !== map.sources.length) {
+      throw new Error(`x_com_bloomberg_sourcesFunctionMappings must have ${map.sources.length} scope trees`);
     }
     const names = map.names ?? [];
-    const scopeList = map.x_com_bloomberg_sourcesFunctionMappings;
+    const result: (OriginalScope|undefined)[] = [];
 
     for (let i = 0; i < scopeList.length; i++) {
       if (!scopeList[i]) {
+        result.push(undefined);
         continue;
       }
       const sourceInfo = this.#sourceInfos[baseSourceIndex + i];
@@ -594,27 +604,38 @@ export class SourceMap {
       let endColumnNumber = 0;
 
       const tokenIter = new TokenIterator(scopes);
-      const entries: ScopeTreeEntry[] = [];
+      const entries: NamedFunctionRange[] = [];
       let atStart = true;
       while (tokenIter.hasNext()) {
         if (atStart) {
           atStart = false;
         } else if (tokenIter.peek() === ',') {
           tokenIter.next();
         } else {
-          // Unexpected character.
-          return;
+          // Unexpected character. Record what we have up until now.
+          break;
         }
         nameIndex += tokenIter.nextVLQ();
         startLineNumber += tokenIter.nextVLQ();
         startColumnNumber += tokenIter.nextVLQ();
         endLineNumber += tokenIter.nextVLQ();
         endColumnNumber += tokenIter.nextVLQ();
-        entries.push(new ScopeTreeEntry(
-            startLineNumber, startColumnNumber, endLineNumber, endColumnNumber, names[nameIndex] ?? '<invalid>'));
+        const name = names[nameIndex];
+        if (name === undefined) {
+          // If the range doesn't have a valid name, ignore it.
+          continue;
+        }
+        entries.push({
+          start: {line: startLineNumber, column: startColumnNumber},
+          end: {line: endLineNumber, column: endColumnNumber},
+          name,
+        });
       }
-      sourceInfo.scopeTree = this.buildScopeTree(entries);
+      result.push(buildOriginalScopes(entries));
+      sourceInfo.scopeTree = this.buildScopeTree(
+          entries.map(e => new ScopeTreeEntry(e.start.line, e.start.column, e.end.line, e.end.column, e.name)));
     }
+    return result;
   }
 
   private buildScopeTree(entries: ScopeTreeEntry[]): ScopeTreeEntry[] {

front_end/core/sdk/SourceMapScopesInfo.ts

@@ -22,7 +22,7 @@ export class SourceMapScopesInfo {
     this.#generatedRanges = generatedRanges;
   }
 
-  addOriginalScopes(scopes: OriginalScope[]): void {
+  addOriginalScopes(scopes: (OriginalScope|undefined)[]): void {
     for (const scope of scopes) {
       this.#originalScopes.push(scope);
     }