Feat: Add definition on hover for variables defined by BitBake

client/README.md

@@ -35,3 +35,8 @@ The go to definition feature currently behaves as follows:
 | class or inc-file | file |
 | recipe | recipe definition and all bbappends |
 | symbol | all symbols within the include hierarchy |
+
+### Show definitions of BitBake's defined variables on hover
+*This functionnality requires to [provide the BitBake's folder](#set-bitbakes-path)*
+
+Place your cursor over a variable. If it is a BitBake defined variable, then its definition from the documentation will be displayed.

server/src/BitBakeDocScanner.ts

@@ -0,0 +1,79 @@
+import path from 'path'
+import fs from 'fs'
+
+type SuffixType = 'layer' | 'providedItem' | undefined
+
+export interface VariableInfos {
+  name: string
+  definition: string
+  validFiles?: RegExp[] // Files on which the variable is defined. If undefined, the variable is defined in all files.
+  suffixType?: SuffixType
+}
+
+type VariableInfosOverride = Partial<VariableInfos>
+
+// Infos that can't be parsed properly from the doc
+const variableInfosOverrides: Record<string, VariableInfosOverride> = {
+  BBFILE_PATTERN: {
+    suffixType: 'layer'
+  },
+  LAYERDEPENDS: {
+    suffixType: 'layer'
+  },
+  LAYERDIR: {
+    validFiles: [/^.*\/conf\/layer.conf$/]
+  },
+  LAYERDIR_RE: {
+    validFiles: [/^.*\/conf\/layer.conf$/]
+  },
+  LAYERVERSION: {
+    suffixType: 'layer'
+  },
+  PREFERRED_PROVIDER: {
+    suffixType: 'providedItem'
+  }
+}
+
+const variablesFolder = 'doc/bitbake-user-manual/bitbake-user-manual-ref-variables.rst'
+const variablesRegexForDoc = /^ {3}:term:`(?<name>[A-Z_]*?)`\n(?<definition>.*?)(?=^ {3}:term:|$(?!\n))/gsm
+
+export class BitBakeDocScanner {
+  private _variablesInfos: Record<string, VariableInfos> = {}
+  private _variablesRegex = /(?!)/g // Initialize with dummy regex that won't match anything so we don't have to check for undefined
+
+  get variablesInfos (): Record<string, VariableInfos> {
+    return this._variablesInfos
+  }
+
+  get variablesRegex (): RegExp {
+    return this._variablesRegex
+  }
+
+  parse (pathToBitbakeFolder: string): void {
+    const file = fs.readFileSync(path.join(pathToBitbakeFolder, variablesFolder), 'utf8')
+    for (const match of file.matchAll(variablesRegexForDoc)) {
+      const name = match.groups?.name
+      // Naive silly inneficient incomplete conversion to markdown
+      const definition = match.groups?.definition
+        .replace(/^ {3}/gm, '')
+        .replace(/:term:|:ref:/g, '')
+        .replace(/\.\. (note|important)::/g, (_match, p1) => { return `**${p1}**` })
+        .replace(/::/g, ':')
+        .replace(/``/g, '`')
+      if (name === undefined || definition === undefined) {
+        return
+      }
+      this._variablesInfos[name] = {
+        name,
+        definition,
+        ...variableInfosOverrides[name]
+      }
+    }
+    const variablesNames = Object.keys(this._variablesInfos)
+    // Sort from longuest to shortest in order to make the regex greedy
+    // Otherwise it would match B before BB_PRESERVE_ENV
+    variablesNames.sort((a, b) => b.length - a.length)
+    const variablesRegExpString = `(${variablesNames.join('|')})`
+    this._variablesRegex = new RegExp(variablesRegExpString, 'gi')
+  }
+}

server/src/server.ts

@@ -12,8 +12,10 @@ import {
   type CompletionItem,
   type Definition,
   ProposedFeatures,
-  TextDocumentSyncKind
+  TextDocumentSyncKind,
+  type Hover
 } from 'vscode-languageserver/node'
+import { BitBakeDocScanner } from './BitBakeDocScanner'
 import { BitBakeProjectScanner } from './BitBakeProjectScanner'
 import { ContextHandler } from './ContextHandler'
 import { SymbolScanner } from './SymbolScanner'
@@ -27,6 +29,7 @@ const documents = new TextDocuments<TextDocument>(TextDocument)
 // Until we manage to fix this, we use this documentMap to store the content of the files
 // Does it have any other purpose?
 const documentMap = new Map< string, string[] >()
+const bitBakeDocScanner = new BitBakeDocScanner()
 const bitBakeProjectScanner: BitBakeProjectScanner = new BitBakeProjectScanner(connection)
 const contextHandler: ContextHandler = new ContextHandler(bitBakeProjectScanner)
 
@@ -53,7 +56,8 @@ connection.onInitialize((params): InitializeResult => {
         commands: [
           'bitbake.rescan-project'
         ]
-      }
+      },
+      hoverProvider: true
     }
   }
 })
@@ -78,6 +82,7 @@ interface BitbakeSettings {
   pathToBashScriptInterpreter: string
   machine: string
   generateWorkingFolder: boolean
+  pathToBitbakeFolder: string
 }
 
 function setSymbolScanner (newSymbolScanner: SymbolScanner | null): void {
@@ -93,6 +98,8 @@ connection.onDidChangeConfiguration((change) => {
   bitBakeProjectScanner.generateWorkingPath = settings.bitbake.generateWorkingFolder
   bitBakeProjectScanner.scriptInterpreter = settings.bitbake.pathToBashScriptInterpreter
   bitBakeProjectScanner.machineName = settings.bitbake.machine
+  const bitBakeFolder = settings.bitbake.pathToBitbakeFolder
+  bitBakeDocScanner.parse(bitBakeFolder)
 })
 
 connection.onDidChangeWatchedFiles((change) => {
@@ -163,5 +170,42 @@ connection.onDefinition((textDocumentPositionParams: TextDocumentPositionParams)
   return contextHandler.getDefinition(textDocumentPositionParams, documentAsText)
 })
 
+connection.onHover(async (params): Promise<Hover | undefined> => {
+  const { position, textDocument } = params
+  const documentAsText = documentMap.get(textDocument.uri)
+  const textLine = documentAsText?.[position.line]
+  if (textLine === undefined) {
+    return undefined
+  }
+  const matches = textLine.matchAll(bitBakeDocScanner.variablesRegex)
+  for (const match of matches) {
+    const name = match[1].toUpperCase()
+    if (name === undefined || match.index === undefined) {
+      continue
+    }
+    const start = match.index
+    const end = start + name.length
+    if ((start > position.character) || (end <= position.character)) {
+      continue
+    }
+
+    const definition = bitBakeDocScanner.variablesInfos[name]?.definition
+    const hover: Hover = {
+      contents: {
+        kind: 'markdown',
+        value: `**${name}**\n___\n${definition}`
+      },
+      range: {
+        start: position,
+        end: {
+          ...position,
+          character: end
+        }
+      }
+    }
+    return hover
+  }
+})
+
 // Listen on the connection
 connection.listen()