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v0.4.34: purge() cancels in-flight download (per-URL cancellation)
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videoCache remove(=purge) 가 다운로드 중인 항목도 취소하도록 per-URL 세대
(DOWNLOAD_GEN) 채널 추가. 기존엔 READY/디스크 최종 파일만 지워서, 느린/큰
영상이 다운로드 중에 evict 되면 완료 후 다시 디스크+READY 에 되살아남.
이제 purge 가 세대를 제거 → download 의 cancelled() 검사(읽기 루프 + 모든
publish 지점)가 실패 → .part/승격 파일 self-clean. clearAll/wipe/clearIndex
도 DOWNLOAD_GEN 정리. 데이터팩 keep(FIFO) 메모리 관리 보장에 필요.

Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
This commit is contained in:
Claude (owner)
2026-06-04 22:40:20 +09:00
parent e31635ef24
commit b53f51a0b4
2 changed files with 58 additions and 18 deletions
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74
src/main/java/com/ejclaw/videoplayer/client/playback/VideoCache.java
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@@ -52,6 +52,18 @@ public final class VideoCache {
*/
private static final AtomicLong CACHE_EPOCH = new AtomicLong(0);
/**
* Per-URL cancellation channel for {@link #purge(String)}. The global {@link #CACHE_EPOCH}
* can only cancel <em>all</em> in-flight downloads at once; a targeted purge needs to stop
* exactly one. Each submitted download captures a unique generation here at submit time;
* {@link #purge(String)} removes the URL's entry, which makes the running download's
* {@link #cancelled(String, long, long)} checks (read loop + every publish point) fail and
* self-clean its {@code .part}/promoted file instead of re-publishing post-purge.
*/
private static final Map<String, Long> DOWNLOAD_GEN = new ConcurrentHashMap<>();
/** Monotonic source for per-download generations stored in {@link #DOWNLOAD_GEN}. */
private static final AtomicLong GEN_SEQ = new AtomicLong(0);
/**
* Single-thread executor that serializes all downloads. Cap enforcement (the total
* cache size check) needs an authoritative view of the cache directory at the moment a
@@ -103,6 +115,12 @@ public final class VideoCache {
/** Server-driven delete of a cached URL. Removes from READY and from disk. */
public static void purge(String url) {
if (url == null || url.isEmpty()) return;
// Cancel any in-flight download of this exact URL first. Dropping its generation
// makes the download thread's cancelled() checks fail, so it deletes its own .part
// (or rolls back a just-promoted file) instead of finishing and re-publishing after
// we've purged. Without this, a slow/large download evicted mid-flight would silently
// reappear on disk + in READY once it completed.
DOWNLOAD_GEN.remove(url);
Path p = READY.remove(url);
if (p == null) {
// Not in this session's index, but the file may still be on disk from a prior run.
@@ -158,6 +176,7 @@ public final class VideoCache {
// Phase 2: drop indexes.
READY.clear();
IN_FLIGHT.clear();
DOWNLOAD_GEN.clear();
// Phase 3: delete files on disk.
int deleted = 0;
@@ -209,7 +228,11 @@ public final class VideoCache {
// CACHE_EPOCH later — any mismatch means clearAll() ran in between and this
// download must abort without publishing.
long epoch = CACHE_EPOCH.get();
DOWNLOAD_POOL.submit(() -> download(url, epoch));
// Register a unique generation for this download so a targeted purge() can cancel
// exactly this URL (see DOWNLOAD_GEN / cancelled()).
long gen = GEN_SEQ.incrementAndGet();
DOWNLOAD_GEN.put(url, gen);
DOWNLOAD_POOL.submit(() -> download(url, epoch, gen));
}
/** Return the local cached file path for this URL, or {@code null} if not yet ready. */
@@ -224,6 +247,7 @@ public final class VideoCache {
public static void clearIndex() {
READY.clear();
IN_FLIGHT.clear();
DOWNLOAD_GEN.clear();
}
/**
@@ -237,6 +261,7 @@ public final class VideoCache {
CACHE_EPOCH.incrementAndGet();
READY.clear();
IN_FLIGHT.clear();
DOWNLOAD_GEN.clear();
int deleted = 0;
int failed = 0;
try {
@@ -283,16 +308,16 @@ public final class VideoCache {
* @return {@code true} if the entry is now published; {@code false} if the
* caller's work was cancelled and {@code path} has been cleaned up.
*/
private static boolean publishIfNotCancelled(String url, Path path, long startEpoch) {
// If the wipe ran between download's pre-move epoch check and Files.move, its
// directory scan won't have seen this just-promoted file. We must delete it here,
// not just bail — otherwise the freshly-moved final file leaks across shutdown.
if (CACHE_EPOCH.get() != startEpoch) {
private static boolean publishIfNotCancelled(String url, Path path, long startEpoch, long startGen) {
// If a wipe (clearAll) or a targeted purge ran between download's pre-move check and
// Files.move, its directory scan won't have seen this just-promoted file. We must
// delete it here, not just bail — otherwise the freshly-moved final file leaks.
if (cancelled(url, startEpoch, startGen)) {
try { Files.deleteIfExists(path); } catch (Throwable ignored) {}
return false;
}
READY.put(url, path);
if (CACHE_EPOCH.get() != startEpoch) {
if (cancelled(url, startEpoch, startGen)) {
READY.remove(url, path);
try { Files.deleteIfExists(path); } catch (Throwable ignored) {}
return false;
@@ -300,7 +325,19 @@ public final class VideoCache {
return true;
}
private static void download(String url, long startEpoch) {
/**
* True if the in-flight download for {@code url} should abort and self-clean. Two channels:
* a global wipe ({@link #clearAll()}/{@link #wipeOnShutdown()} bumped {@link #CACHE_EPOCH}),
* or a targeted {@link #purge(String)} that removed/replaced this URL's generation in
* {@link #DOWNLOAD_GEN}.
*/
private static boolean cancelled(String url, long startEpoch, long startGen) {
if (CACHE_EPOCH.get() != startEpoch) return true;
Long cur = DOWNLOAD_GEN.get(url);
return cur == null || cur.longValue() != startGen;
}
private static void download(String url, long startEpoch, long startGen) {
Path cacheDir = cacheDir();
Path partPath = null;
try {
@@ -311,8 +348,8 @@ public final class VideoCache {
}
// Pre-flight cancellation check — if clearAll already ran between submit and now,
// skip the whole thing. Avoids creating directories / .part files post-clear.
if (CACHE_EPOCH.get() != startEpoch) {
VideoPlayerMod.LOG.info("[{}] preload: cancelled before start (clearAll ran) — {}",
if (cancelled(url, startEpoch, startGen)) {
VideoPlayerMod.LOG.info("[{}] preload: cancelled before start (clearAll/purge ran) — {}",
VideoPlayerMod.MOD_ID, url);
return;
}
@@ -326,8 +363,8 @@ public final class VideoCache {
// Resume-friendly: if the file's already on disk from an earlier session, just
// index it without re-downloading.
if (Files.exists(finalPath) && Files.size(finalPath) > 0) {
if (!publishIfNotCancelled(url, finalPath, startEpoch)) {
VideoPlayerMod.LOG.info("[{}] preload: reindex cancelled (clearAll ran) — {}",
if (!publishIfNotCancelled(url, finalPath, startEpoch, startGen)) {
VideoPlayerMod.LOG.info("[{}] preload: reindex cancelled (clearAll/purge ran) — {}",
VideoPlayerMod.MOD_ID, url);
return;
}
@@ -378,7 +415,7 @@ public final class VideoCache {
// Cancellation check inside the loop. Break (not return) so the try-with
// closes the output stream first — on Windows, deleting an open .part can
// fail with AccessDeniedException, so we always close before deleting.
if (CACHE_EPOCH.get() != startEpoch) {
if (cancelled(url, startEpoch, startGen)) {
cancelled = true;
break;
}
@@ -416,8 +453,8 @@ public final class VideoCache {
// Pre-move cancellation check. If clearAll ran during the read loop, abort
// before promoting .part to final — saves a wasted move + delete.
if (CACHE_EPOCH.get() != startEpoch) {
VideoPlayerMod.LOG.info("[{}] preload: cancelled before move (clearAll ran) — {}",
if (cancelled(url, startEpoch, startGen)) {
VideoPlayerMod.LOG.info("[{}] preload: cancelled before move (clearAll/purge ran) — {}",
VideoPlayerMod.MOD_ID, url);
try { Files.deleteIfExists(partPath); } catch (Throwable ignored) {}
return;
@@ -431,8 +468,8 @@ public final class VideoCache {
// the window between READY.put and the "완료" notification (clearAll wipes
// READY then we re-publish + emit stale completion chat). publishIfNotCancelled
// rolls back both READY and the on-disk file if the epoch moved at any time.
if (!publishIfNotCancelled(url, finalPath, startEpoch)) {
VideoPlayerMod.LOG.info("[{}] preload: cancelled at publish (clearAll ran) — {}",
if (!publishIfNotCancelled(url, finalPath, startEpoch, startGen)) {
VideoPlayerMod.LOG.info("[{}] preload: cancelled at publish (clearAll/purge ran) — {}",
VideoPlayerMod.MOD_ID, url);
return;
}
@@ -451,6 +488,9 @@ public final class VideoCache {
}
} finally {
IN_FLIGHT.remove(url);
// Only clear our own generation — a re-preload after a purge may have installed a
// newer gen for this URL that must survive.
DOWNLOAD_GEN.remove(url, startGen);
}
}