1 files changed, 131 insertions, 13 deletions

diff --git a/web/index.php b/web/index.php
index 361fdcf..fd0a396 100644
--- a/web/index.php
+++ b/web/index.php
@@ -19,9 +19,10 @@ declare(strict_types=1);
  *   bin/client/zagan-bet-client-3.1.1-linux-x86_64
  *   bin/server/zagan-bet-server-3.1.1-linux-x86_64
  *
- * The hashes are computed per request with hash_file(). That is a few tens of
- * milliseconds for a handful of builds; add a cache keyed on mtime if the
- * directory ever grows.
+ * SHA-256 values are cached in a JSON file keyed on size and mtime, so a file
+ * is only re-read when it changes. The cache lives in the system temp
+ * directory by default (the web root is often not writable by the PHP user);
+ * set ZAGAN_HASH_CACHE to put it somewhere else.
  */
 
 const KINDS = [
@@ -68,10 +69,99 @@ function human_size(int $bytes): string
 }
 
 /**
- * @return array{version:string,platform:string,arch:string,file:string,size:int,mtime:int,sha256:string}|null
+ * Hash to use for a published file, reusing the cached value when the file has
+ * not changed since it was hashed.
+ *
+ * A cached hash is valid only when the size and mtime still match and the hash
+ * was taken at or after the file's mtime, so a restored or touched file is
+ * re-read.
+ *
+ * @param array{files:array<string,array{size:int,mtime:int,sha256:string,hashed_at:int}>} $cache
+ */
+function cached_hash(
+    string $key,
+    string $path,
+    int $size,
+    int $mtime,
+    array &$cache,
+    bool &$dirty
+): ?string {
+    $entry = $cache['files'][$key] ?? null;
+    if (
+        is_array($entry)
+        && ($entry['size'] ?? null) === $size
+        && ($entry['mtime'] ?? null) === $mtime
+        && (int) ($entry['hashed_at'] ?? 0) >= $mtime
+        && isset($entry['sha256'])
+        && is_string($entry['sha256'])
+        && preg_match('/\A[0-9a-f]{64}\z/', $entry['sha256']) === 1
+    ) {
+        return $entry['sha256'];
+    }
+
+    $hash = hash_file('sha256', $path);
+    if ($hash === false) {
+        return null;
+    }
+
+    $cache['files'][$key] = [
+        'size' => $size,
+        'mtime' => $mtime,
+        'sha256' => $hash,
+        'hashed_at' => time(),
+    ];
+    $dirty = true;
+
+    return $hash;
+}
+
+/** @return array{files:array<string,array{size:int,mtime:int,sha256:string,hashed_at:int}>} */
+function load_hash_cache(string $path): array
+{
+    $raw = @file_get_contents($path);
+    if ($raw === false || $raw === '') {
+        return ['files' => []];
+    }
+    $decoded = json_decode($raw, true);
+    if (!is_array($decoded) || !isset($decoded['files']) || !is_array($decoded['files'])) {
+        return ['files' => []];
+    }
+
+    return ['files' => $decoded['files']];
+}
+
+/**
+ * Best effort: a read-only web root, a full disk or a racing writer must never
+ * break the page, so failures are ignored and the next request recomputes.
+ *
+ * @param array{files:array<string,array{size:int,mtime:int,sha256:string,hashed_at:int}>} $cache
  */
-function read_release(string $kind, string $directory, string $entry): ?array
+function save_hash_cache(string $path, array $cache): void
 {
+    $json = json_encode($cache, JSON_UNESCAPED_SLASHES);
+    if ($json === false) {
+        return;
+    }
+    $directory = dirname($path);
+    $temporary = @tempnam($directory, '.zagan-hashes-');
+    if ($temporary === false) {
+        return;
+    }
+    if (@file_put_contents($temporary, $json, LOCK_EX) === false || !@rename($temporary, $path)) {
+        @unlink($temporary);
+    }
+}
+
+/**
+ * @return array{version:string,platform:string,arch:string,file:string,size:int,mtime:int,sha256:string}|null
+ */
+function read_release(
+    string $kind,
+    string $directory,
+    string $entry,
+    array &$cache,
+    bool &$dirty
+): ?array {
     $pattern = '/^zagan-bet-' . preg_quote($kind, '/')
         . '-v?(\d+\.\d+\.\d+)-([a-z]+)-([a-z0-9_]+)(\.exe)?$/i';
     if (preg_match($pattern, $entry, $matches) !== 1) {
@@ -92,8 +182,13 @@ function read_release(string $kind, string $directory, string $entry): ?array
     }
 
     $size = filesize($real);
-    $hash = hash_file('sha256', $real);
-    if ($size === false || $hash === false) {
+    $mtime = filemtime($real);
+    if ($size === false || $mtime === false) {
+        return null;
+    }
+
+    $hash = cached_hash($kind . '/' . $entry, $real, $size, $mtime, $cache, $dirty);
+    if ($hash === null) {
         return null;
     }
 
@@ -103,7 +198,7 @@ function read_release(string $kind, string $directory, string $entry): ?array
         'arch' => strtolower($matches[3]),
         'file' => $entry,
         'size' => $size,
-        'mtime' => filemtime($real) ?: 0,
+        'mtime' => $mtime,
         'sha256' => $hash,
     ];
 }
@@ -113,6 +208,16 @@ if ($base === '.' || $base === '/') {
     $base = '';
 }
 
+$cachePath = getenv('ZAGAN_HASH_CACHE');
+if (!is_string($cachePath) || $cachePath === '') {
+    $cachePath = rtrim(sys_get_temp_dir(), DIRECTORY_SEPARATOR)
+        . DIRECTORY_SEPARATOR . 'zagan-bet-hashes-'
+        . substr(hash('sha256', __DIR__), 0, 16) . '.json';
+}
+$cache = load_hash_cache($cachePath);
+$cacheDirty = false;
+$seen = [];
+
 $releases = [];
 $newest = 0;
 
@@ -127,10 +232,11 @@ foreach (KINDS as $kind => $meta) {
                 if ($entry === '.' || $entry === '..') {
                     continue;
                 }
-                $release = read_release($kind, $directory, $entry);
+                $release = read_release($kind, $directory, $entry, $cache, $cacheDirty);
                 if ($release === null) {
                     continue;
                 }
+                $seen[$kind . '/' . $entry] = true;
                 $release['href'] = $base . '/bin/' . $kind . '/' . rawurlencode($release['file']);
                 $found[] = $release;
                 $newest = max($newest, $release['mtime']);
@@ -156,19 +262,30 @@ foreach (KINDS as $kind => $meta) {
 
     $releases[$kind] = $found;
 }
+
+// Drop cache entries for files that are no longer published.
+foreach (array_keys($cache['files']) as $key) {
+    if (!isset($seen[$key])) {
+        unset($cache['files'][$key]);
+        $cacheDirty = true;
+    }
+}
+if ($cacheDirty) {
+    save_hash_cache($cachePath, $cache);
+}
 ?>
 <!doctype html>
 <html lang="en">
 <head>
 <meta charset="utf-8">
 <meta name="viewport" content="width=device-width, initial-scale=1">
-<title>Download · zagan.bet</title>
+<title>żagań.bet</title>
 <meta name="description" content="Official zagan.bet client and server downloads.">
 <meta http-equiv="Content-Security-Policy" content="default-src 'none'">
 </head>
 <body>
 
-<h1>zagan.bet</h1>
+<h1>żagań.bet</h1>
 <p>Official client and server builds.</p>
 <?php if ($newest > 0): ?>
 <p>Builds published <?= e(gmdate('j M Y H:i', $newest)) ?> UTC.</p>
@@ -181,7 +298,7 @@ foreach (KINDS as $kind => $meta) {
 <?php else: ?>
 <ul>
 <?php foreach ($releases['client'] as $release): ?>
-<li><a href="<?= e($release['href']) ?>" download><?= e(PLATFORMS[$release['platform']] ?? ucfirst($release['platform'])) ?> <?= e($release['arch']) ?><?php if (isset(ARCHES[$release['arch']])): ?> (<?= e(ARCHES[$release['arch']]) ?>)<?php endif; ?> — version <?= e($release['version']) ?> — <?= e(human_size($release['size'])) ?></a></li>
+<li><a href="<?= e($release['href']) ?>" download><?= e(PLATFORMS[$release['platform']] ?? ucfirst($release['platform'])) ?> <?= e($release['arch']) ?><?php if (isset(ARCHES[$release['arch']])): ?> (<?= e(ARCHES[$release['arch']]) ?>)<?php endif; ?> v<?= e($release['version']) ?> — <?= e(human_size($release['size'])) ?></a></li>
 <?php endforeach; ?>
 </ul>
 <?php endif; ?>
@@ -193,7 +310,7 @@ foreach (KINDS as $kind => $meta) {
 <?php else: ?>
 <ul>
 <?php foreach ($releases['server'] as $release): ?>
-<li><a href="<?= e($release['href']) ?>" download><?= e(PLATFORMS[$release['platform']] ?? ucfirst($release['platform'])) ?> <?= e($release['arch']) ?><?php if (isset(ARCHES[$release['arch']])): ?> (<?= e(ARCHES[$release['arch']]) ?>)<?php endif; ?> — version <?= e($release['version']) ?> — <?= e(human_size($release['size'])) ?></a></li>
+<li><a href="<?= e($release['href']) ?>" download><?= e(PLATFORMS[$release['platform']] ?? ucfirst($release['platform'])) ?> <?= e($release['arch']) ?><?php if (isset(ARCHES[$release['arch']])): ?> (<?= e(ARCHES[$release['arch']]) ?>)<?php endif; ?> v<?= e($release['version']) ?> — <?= e(human_size($release['size'])) ?></a></li>
 <?php endforeach; ?>
 </ul>
 <?php endif; ?>
@@ -222,5 +339,6 @@ echo e($sums);
 
 <p>Windows: run the <code>.exe</code> from Windows Terminal or another real terminal.</p>
 
+<p>When lost, execute <code>help</code> command inside zagan.bet client. Server binary supports <code>--help</code> flag</p>
 </body>
 </html>