chore: sync fsRead with VSC branch. (#936)

* chore: sync fsRead tool with recent changes

* docs: add todo for likely next steps

* test: add a test for stream usage

* chore: update spec formatting to line up

Author: Hweinstock

server/aws-lsp-codewhisperer/src/language-server/agenticChat/tools/fsRead.test.ts

@@ -43,9 +43,24 @@ describe('FsRead Tool', () => {
         tempFolder.clear()
     })
 
-    it('throws if path is empty', async () => {
+    it('invalidates empty path', async () => {
         const fsRead = new FsRead(features)
-        await assert.rejects(() => fsRead.invoke({ path: '' }))
+        await assert.rejects(
+            fsRead.validate({ path: '' }),
+            /Path cannot be empty/i,
+            'Expected an error about empty path'
+        )
+    })
+
+    it('invalidates non-existent paths', async () => {
+        const filePath = path.join(tempFolder.path, 'no_such_file.txt')
+        const fsRead = new FsRead(features)
+
+        await assert.rejects(
+            fsRead.validate({ path: filePath }),
+            /does not exist or cannot be accessed/i,
+            'Expected an error indicating the path does not exist'
+        )
     })
 
     it('reads entire file', async () => {
@@ -70,27 +85,6 @@ describe('FsRead Tool', () => {
         assert.strictEqual(result.output.content, 'B\nC\nD')
     })
 
-    it('throws error if path does not exist', async () => {
-        const filePath = path.join(tempFolder.path, 'no_such_file.txt')
-        const fsRead = new FsRead(features)
-
-        await assert.rejects(fsRead.invoke({ path: filePath }))
-    })
-
-    it('throws error if content exceeds 30KB', async function () {
-        const bigContent = 'x'.repeat(35_000)
-
-        const filePath = await tempFolder.write('bigFile.txt', bigContent)
-
-        const fsRead = new FsRead(features)
-
-        await assert.rejects(
-            fsRead.invoke({ path: filePath }),
-            /This tool only supports reading \d+ bytes at a time/i,
-            'Expected a size-limit error'
-        )
-    })
-
     it('invalid line range', async () => {
         const filePath = await tempFolder.write('rangeTest.txt', '1\n2\n3')
         const fsRead = new FsRead(features)
@@ -100,4 +94,17 @@ describe('FsRead Tool', () => {
         assert.strictEqual(result.output.kind, 'text')
         assert.strictEqual(result.output.content, '')
     })
+
+    it('updates the stream', async () => {
+        const fsRead = new FsRead(features)
+        const chunks = []
+        const stream = new WritableStream({
+            write: c => {
+                chunks.push(c)
+            },
+        })
+        await fsRead.queueDescription({ path: 'this/is/my/path' }, stream)
+        assert.ok(chunks.length > 0)
+        assert.ok(!stream.locked)
+    })
 })

server/aws-lsp-codewhisperer/src/language-server/agenticChat/tools/fsRead.ts

@@ -1,12 +1,8 @@
-/*!
- * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
- * SPDX-License-Identifier: Apache-2.0
- */
 import { sanitize } from '@aws/lsp-core/out/util/path'
-import { InvokeOutput, maxToolResponseSize } from './toolShared'
+import { InvokeOutput } from './toolShared'
 import { Features } from '@aws/language-server-runtimes/server-interface/server'
 
-// Port of https://github.com/aws/aws-toolkit-vscode/blob/10bb1c7dc45f128df14d749d95905c0e9b808096/packages/core/src/codewhispererChat/tools/fsRead.ts#L17
+// Port of https://github.com/aws/aws-toolkit-vscode/blob/8e00eefa33f4eee99eed162582c32c270e9e798e/packages/core/src/codewhispererChat/tools/fsRead.ts#L17
 
 export interface FsReadParams {
     path: string
@@ -22,6 +18,41 @@ export class FsRead {
         this.workspace = features.workspace
     }
 
+    public async validate(params: FsReadParams): Promise<void> {
+        this.logging.debug(`Validating path: ${params.path}`)
+        if (!params.path || params.path.trim().length === 0) {
+            throw new Error('Path cannot be empty.')
+        }
+
+        const fileExists = await this.workspace.fs.exists(params.path)
+        if (!fileExists) {
+            throw new Error(`Path: "${params.path}" does not exist or cannot be accessed.`)
+        }
+
+        this.logging.debug(`Validation succeeded for path: ${params.path}`)
+    }
+
+    public async queueDescription(params: FsReadParams, updates: WritableStream) {
+        const updateWriter = updates.getWriter()
+        await updateWriter.write(`Reading file: ${params.path}]`)
+
+        const [start, end] = params.readRange ?? []
+
+        if (start && end) {
+            await updateWriter.write(`from line ${start} to ${end}`)
+        } else if (start) {
+            if (start > 0) {
+                await updateWriter.write(`from line ${start} to end of file`)
+            } else {
+                await updateWriter.write(`${start} line from the end of file to end of file`)
+            }
+        } else {
+            await updateWriter.write('all lines')
+        }
+        await updateWriter.close()
+        updateWriter.releaseLock()
+    }
+
     public async invoke(params: FsReadParams): Promise<InvokeOutput> {
         const path = sanitize(params.path)
         const fileContents = await this.readFile(path)
@@ -37,7 +68,7 @@ export class FsRead {
     private handleFileRange(params: FsReadParams, fullText: string): InvokeOutput {
         if (!params.readRange || params.readRange.length === 0) {
             this.logging.log('No range provided. returning entire file.')
-            return this.createOutput(this.enforceMaxSize(fullText))
+            return this.createOutput(fullText)
         }
 
         const lines = fullText.split('\n')
@@ -49,7 +80,7 @@ export class FsRead {
 
         this.logging.log(`Reading file: ${params.path}, lines ${start + 1}-${end + 1}`)
         const slice = lines.slice(start, end + 1).join('\n')
-        return this.createOutput(this.enforceMaxSize(slice))
+        return this.createOutput(slice)
     }
 
     private parseLineRange(lineCount: number, range: number[]): [number, number] {
@@ -69,17 +100,6 @@ export class FsRead {
         return [finalStart, finalEnd]
     }
 
-    private enforceMaxSize(content: string): string {
-        const byteCount = Buffer.byteLength(content, 'utf8')
-        if (byteCount > maxToolResponseSize) {
-            throw new Error(
-                `This tool only supports reading ${maxToolResponseSize} bytes at a time.
-                You tried to read ${byteCount} bytes. Try executing with fewer lines specified.`
-            )
-        }
-        return content
-    }
-
     private createOutput(content: string): InvokeOutput {
         return {
             output: {
@@ -93,7 +113,7 @@ export class FsRead {
         return {
             name: 'fsRead',
             description:
-                'A tool for reading a file. \n* This tool returns the contents of a file, and the optional `readRange` determines what range of lines will be read from the specified file.',
+                'A tool for reading a file.\n * This tool returns the contents of a file, and the optional `readRange` determines what range of lines will be read from the specified file',
             inputSchema: {
                 type: 'object',
                 properties: {
@@ -103,7 +123,7 @@ export class FsRead {
                     },
                     readRange: {
                         description:
-                            'Optional parameter when reading files.\n* If none is given, the full file is shown. If provided, the file will be shown in the indicated line number range, e.g. [11, 12] will show lines 11 and 12. Indexing at 1 to start. Setting `[startLine, -1]` shows all lines from `startLine` to the end of the file.',
+                            'Optional parameter when reading files.\n * If none is given, the full file is shown. If provided, the file will be shown in the indicated line number range, e.g. [11, 12] will show lines 11 and 12. Indexing at 1 to start. Setting `[startLine, -1]` shows all lines from `startLine` to the end of the file.',
                         type: 'array',
                         items: {
                             type: 'number',

server/aws-lsp-codewhisperer/src/language-server/agenticChat/tools/toolServer.ts

@@ -10,7 +10,12 @@ export const FsToolsServer: Server = ({ workspace, logging, agent }) => {
 
     const listDirectoryTool = new ListDirectory({ workspace, logging })
 
-    agent.addTool(fsReadTool.getSpec(), (input: FsReadParams) => fsReadTool.invoke(input))
+    agent.addTool(fsReadTool.getSpec(), async (input: FsReadParams) => {
+        // TODO: fill in logic for handling invalid tool invocations
+        // TODO: implement chat streaming via queueDescription.
+        await fsReadTool.validate(input)
+        await fsReadTool.invoke(input)
+    })
 
     agent.addTool(fsWriteTool.getSpec(), (input: FsWriteParams) => fsWriteTool.invoke(input))
 

server/aws-lsp-codewhisperer/src/language-server/agenticChat/tools/toolShared.ts

@@ -1,5 +1,3 @@
-export const maxToolResponseSize = 30720 // 30KB
-
 export interface InvokeOutput {
     output:
         | {