1 files changed, 138 insertions, 0 deletions
diff --git a/scripts/cache/files.ts b/scripts/cache/files.ts
new file mode 100644
index 0000000..e2bdf8b
--- /dev/null
+++ b/scripts/cache/files.ts
@@ -0,0 +1,138 @@
+import { $ } from 'bun';
+import { mkdir, readdir, rm, exists } from 'fs/promises';
+import { join, relative, sep } from 'path';
+import type { CacheMetadata, FileMetadata } from './utils';
+
+export async function calculateFileChecksum(filePath: string): Promise<string> {
+    const fileBlob = Bun.file(filePath);
+    const size = fileBlob.size;
+
+    const hasher = new Bun.CryptoHasher('sha256');
+    if (size <= 10 * 1024 * 1024 /** 10MB */)
+        return hasher.update(await fileBlob.arrayBuffer()).digest('hex');
+
+    const reader = fileBlob.stream().getReader();
+    while (true) {
+        const { done, value } = await reader.read();
+        if (done) break;
+        if (value) hasher.update(value);
+    }
+
+    return hasher.digest('hex');
+}
+
+export async function calculateDirectoryChecksums(
+    paths: string[]
+): Promise<Record<string, FileMetadata>> {
+    const files: Record<string, FileMetadata> = {};
+
+    for (const path of paths) {
+        const entries = await readdir(path, {
+            recursive: true,
+            withFileTypes: true
+        });
+
+        await Promise.all(
+            entries
+                .filter((entry) => entry.isFile())
+                .map(async (entry) => {
+                    const fullPath = join(entry.parentPath, entry.name);
+                    const relativePath = relative('.', fullPath).split(sep).join('/');
+
+                    const size = Bun.file(fullPath).size;
+                    const checksum = await calculateFileChecksum(fullPath);
+
+                    files[relativePath] = { checksum, size };
+                })
+        );
+    }
+
+    return files;
+}
+
+export async function validateCache(metadata: CacheMetadata): Promise<boolean> {
+    console.log('Validating cache...');
+    let valid = 0;
+    let invalid = 0;
+    let missing = 0;
+
+    const totalFiles = Object.keys(metadata.files).length;
+
+    for (const [filePath, fileInfo] of Object.entries(metadata.files)) {
+        const fullPath = join('.', filePath);
+
+        if (!(await exists(fullPath))) {
+            missing++;
+            continue;
+        }
+
+        try {
+            const actualChecksum = await calculateFileChecksum(fullPath);
+            if (actualChecksum === fileInfo.checksum) valid++;
+            else invalid++;
+        } catch (e) {
+            invalid++;
+        }
+    }
+
+    const isValid = invalid === 0 && missing === 0;
+
+    if (isValid) {
+        console.log(`Cache is valid: ${valid} files matched`);
+    } else {
+        console.log(
+            `Cache validation failed: ${valid} valid, ${invalid} invalid, ${missing} missing (total: ${totalFiles})`
+        );
+    }
+
+    return isValid;
+}
+
+export async function extractTar(tarPath: string): Promise<void> {
+    const compressedData = await Bun.file(tarPath).arrayBuffer();
+    const decompressed = Bun.zstdDecompressSync(new Uint8Array(compressedData));
+
+    // Write decompressed tar to temp file
+    const tempTarPath = tarPath + '.tmp';
+    await Bun.write(tempTarPath, decompressed);
+
+    await $`tar -xf ${tempTarPath}`.quiet().finally(async () => {
+        await rm(tempTarPath).catch(() => {});
+    });
+}
+
+export async function compressToTar(
+    paths: string[],
+    outputPath: string
+): Promise<Record<string, FileMetadata>> {
+    const checksums = await calculateDirectoryChecksums(paths);
+
+    const tempTarPath = outputPath + '.tmp';
+    await $`tar -cf ${tempTarPath} ${paths}`.quiet();
+
+    try {
+        const tarData = await Bun.file(tempTarPath).arrayBuffer();
+        const compressed = Bun.zstdCompressSync(new Uint8Array(tarData));
+        await Bun.write(outputPath, compressed);
+    } finally {
+        await rm(tempTarPath).catch(() => {});
+    }
+
+    return checksums;
+}
+
+export async function ensureDir(dir: string): Promise<void> {
+    if (!(await exists(dir))) {
+        await mkdir(dir, { recursive: true });
+    }
+}
+
+export async function cleanupDir(dir: string): Promise<void> {
+    try {
+        await rm(dir, { recursive: true, force: true });
+    } catch (e: any) {
+        if (e.code !== 'EBUSY' && e.code !== 'ENOTEMPTY') {
+            throw e;
+        }
+    }
+}