Change Runnable.bin -> Runnable.kind

As per matklad, we now pass the responsibility for finding the binary to the frontend.
Also, added caching for finding the binary path to reduce
the amount of filesystem interactions.

1 files changed, 174 insertions, 0 deletions

diff --git a/editors/code/src/toolchain.ts b/editors/code/src/toolchain.ts
new file mode 100644
index 000000000..80a7915e9
--- /dev/null
+++ b/editors/code/src/toolchain.ts
@@ -0,0 +1,174 @@
+import * as cp from 'child_process';
+import * as os from 'os';
+import * as path from 'path';
+import * as fs from 'fs';
+import * as readline from 'readline';
+import { OutputChannel } from 'vscode';
+import { log, memoize } from './util';
+
+interface CompilationArtifact {
+    fileName: string;
+    name: string;
+    kind: string;
+    isTest: boolean;
+}
+
+export interface ArtifactSpec {
+    cargoArgs: string[];
+    filter?: (artifacts: CompilationArtifact[]) => CompilationArtifact[];
+}
+
+export class Cargo {
+    constructor(readonly rootFolder: string, readonly output: OutputChannel) { }
+
+    // Made public for testing purposes
+    static artifactSpec(args: readonly string[]): ArtifactSpec {
+        const cargoArgs = [...args, "--message-format=json"];
+
+        // arguments for a runnable from the quick pick should be updated.
+        // see crates\rust-analyzer\src\main_loop\handlers.rs, handle_code_lens
+        switch (cargoArgs[0]) {
+            case "run": cargoArgs[0] = "build"; break;
+            case "test": {
+                if (!cargoArgs.includes("--no-run")) {
+                    cargoArgs.push("--no-run");
+                }
+                break;
+            }
+        }
+
+        const result: ArtifactSpec = { cargoArgs: cargoArgs };
+        if (cargoArgs[0] === "test") {
+            // for instance, `crates\rust-analyzer\tests\heavy_tests\main.rs` tests
+            // produce 2 artifacts: {"kind": "bin"} and {"kind": "test"}
+            result.filter = (artifacts) => artifacts.filter(it => it.isTest);
+        }
+
+        return result;
+    }
+
+    private async getArtifacts(spec: ArtifactSpec): Promise<CompilationArtifact[]> {
+        const artifacts: CompilationArtifact[] = [];
+
+        try {
+            await this.runCargo(spec.cargoArgs,
+                message => {
+                    if (message.reason === 'compiler-artifact' && message.executable) {
+                        const isBinary = message.target.crate_types.includes('bin');
+                        const isBuildScript = message.target.kind.includes('custom-build');
+                        if ((isBinary && !isBuildScript) || message.profile.test) {
+                            artifacts.push({
+                                fileName: message.executable,
+                                name: message.target.name,
+                                kind: message.target.kind[0],
+                                isTest: message.profile.test
+                            });
+                        }
+                    } else if (message.reason === 'compiler-message') {
+                        this.output.append(message.message.rendered);
+                    }
+                },
+                stderr => this.output.append(stderr),
+            );
+        } catch (err) {
+            this.output.show(true);
+            throw new Error(`Cargo invocation has failed: ${err}`);
+        }
+
+        return spec.filter?.(artifacts) ?? artifacts;
+    }
+
+    async executableFromArgs(args: readonly string[]): Promise<string> {
+        const artifacts = await this.getArtifacts(Cargo.artifactSpec(args));
+
+        if (artifacts.length === 0) {
+            throw new Error('No compilation artifacts');
+        } else if (artifacts.length > 1) {
+            throw new Error('Multiple compilation artifacts are not supported.');
+        }
+
+        return artifacts[0].fileName;
+    }
+
+    private runCargo(
+        cargoArgs: string[],
+        onStdoutJson: (obj: any) => void,
+        onStderrString: (data: string) => void
+    ): Promise<number> {
+        return new Promise((resolve, reject) => {
+            const cargo = cp.spawn(cargoPath(), cargoArgs, {
+                stdio: ['ignore', 'pipe', 'pipe'],
+                cwd: this.rootFolder
+            });
+
+            cargo.on('error', err => reject(new Error(`could not launch cargo: ${err}`)));
+
+            cargo.stderr.on('data', chunk => onStderrString(chunk.toString()));
+
+            const rl = readline.createInterface({ input: cargo.stdout });
+            rl.on('line', line => {
+                const message = JSON.parse(line);
+                onStdoutJson(message);
+            });
+
+            cargo.on('exit', (exitCode, _) => {
+                if (exitCode === 0)
+                    resolve(exitCode);
+                else
+                    reject(new Error(`exit code: ${exitCode}.`));
+            });
+        });
+    }
+}
+
+/** Mirrors `ra_toolchain::cargo()` implementation */
+export function cargoPath(): string {
+    return getPathForExecutable("cargo");
+}
+
+/** Mirrors `ra_toolchain::get_path_for_executable()` implementation */
+export const getPathForExecutable = memoize(
+    // We apply caching to decrease file-system interactions
+    (executableName: "cargo" | "rustc" | "rustup"): string => {
+        {
+            const envVar = process.env[executableName.toUpperCase()];
+            if (envVar) return envVar;
+        }
+
+        if (lookupInPath(executableName)) return executableName;
+
+        try {
+            // hmm, `os.homedir()` seems to be infallible
+            // it is not mentioned in docs and cannot be infered by the type signature...
+            const standardPath = path.join(os.homedir(), ".cargo", "bin", executableName);
+
+            if (isFile(standardPath)) return standardPath;
+        } catch (err) {
+            log.error("Failed to read the fs info", err);
+        }
+        return executableName;
+    }
+);
+
+function lookupInPath(exec: string): boolean {
+    const paths = process.env.PATH ?? "";;
+
+    const candidates = paths.split(path.delimiter).flatMap(dirInPath => {
+        const candidate = path.join(dirInPath, exec);
+        return os.type() === "Windows_NT"
+            ? [candidate, `${candidate}.exe`]
+            : [candidate];
+    });
+
+    return candidates.some(isFile);
+}
+
+function isFile(suspectPath: string): boolean {
+    // It is not mentionned in docs, but `statSync()` throws an error when
+    // the path doesn't exist
+    try {
+        return fs.statSync(suspectPath).isFile();
+    } catch {
+        return false;
+    }
+}