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Systems 6: the Project tree's folders and external edits register with the one watcher #117

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Merged
Pelotrio merged 4 commits into from
Oct 1, 2026
Merged

Systems 6: the Project tree's folders and external edits register with the one watcher #117

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b24d03c
The Project tree's folders and external edits register with the one F…
Pelotrio Sep 30, 2026
330db57
Guard junction tests and discard superseded external saves
Pelotrio Sep 30, 2026
e5d2534
Keep watcher callbacks paused through nested file operations
Pelotrio Sep 30, 2026
30cee53
Limit watcher recovery and revalidate external save adoption
Pelotrio Sep 30, 2026
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104 changes: 34 additions & 70 deletions companion/src/main/java/com/github/minecraft_ta/totalDebugCompanion/pack/ExternalEdits.java
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Original file line number Diff line number Diff line change
@@ -1,18 +1,15 @@
package com.github.minecraft_ta.totalDebugCompanion.pack;

import com.github.minecraft_ta.totalDebugCompanion.resource.ResourceLoader;
import com.github.minecraft_ta.totalDebugCompanion.util.FileWatch;
import com.github.minecraft_ta.totalDebugCompanion.util.Strand;
import com.github.minecraft_ta.totalDebugCompanion.util.Workers;

import java.awt.Desktop;
import java.io.IOException;
import java.lang.ProcessBuilder.Redirect;
import java.nio.file.ClosedWatchServiceException;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.StandardWatchEventKinds;
import java.nio.file.WatchEvent;
import java.nio.file.WatchKey;
import java.nio.file.WatchService;
import java.util.Arrays;
import java.util.List;
import java.util.Locale;
Expand All @@ -22,10 +19,7 @@
import java.util.concurrent.CompletionException;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.function.BiConsumer;

/**
Expand All @@ -43,10 +37,8 @@ public final class ExternalEdits implements AutoCloseable {
private final ResourceEdits edits;
/** The files followed, by absolute file. */
private final Map<Path, Followed> followed = new ConcurrentHashMap<>();
/** The folders watched, by folder. */
private final Map<Path, WatchKey> folders = new ConcurrentHashMap<>();
private WatchService watcher;
private ScheduledExecutorService settle;
/** Where a save is taken, one at a time, as it is adopted in order. */
private final Strand strand = Workers.strand();
private boolean closed;

/** A followed file, what it held when a program first opened it, and who hears about its saves. */
Expand All @@ -55,7 +47,10 @@ private static final class Followed {
final Path pack;
final byte[] before;
final List<BiConsumer<ResourceEdits.Saved, Throwable>> listeners = new CopyOnWriteArrayList<>();
Runnable unwatch = () -> { };
ScheduledFuture<?> pending;
/** Counts the writes seen, so a take handed on before a later write takes nothing. Under the edits' lock. */
long writes;

Followed(String path, Path pack, byte[] before) {
this.path = path;
Expand All @@ -79,7 +74,7 @@ public void open(String path, Path pack, String program) throws IOException {
launch(program, file);
} catch (IOException | RuntimeException failed) {
// Nothing was opened, so nothing else's saves are taken: only a file followed before stays followed.
if (!followedBefore) this.followed.remove(file);
if (!followedBefore) stopFollowing(file);
throw failed;
}
}
Expand All @@ -93,14 +88,12 @@ Path follow(String path, Path pack) throws IOException {
if (!Files.isRegularFile(file)) throw new IOException(file + " does not exist");
synchronized (this) {
if (this.closed) throw new IOException("The project is closing");
if (this.watcher == null) start();
// A folder deleted and made again since lost its watch, which is registered anew.
Path folder = file.getParent();
if (!this.folders.containsKey(folder)) {
this.folders.put(folder, folder.register(this.watcher, StandardWatchEventKinds.ENTRY_CREATE,
StandardWatchEventKinds.ENTRY_MODIFY));
if (!this.followed.containsKey(file)) {
Followed followed = new Followed(path, pack, Files.readAllBytes(file));
Path name = file.getFileName();
followed.unwatch = FileWatch.shared().watch(file.getParent(), name::equals, () -> settle(followed));
this.followed.put(file, followed);
}
if (!this.followed.containsKey(file)) this.followed.put(file, new Followed(path, pack, Files.readAllBytes(file)));
}
return file;
}
Expand All @@ -121,51 +114,26 @@ public boolean follows(String path, Path pack) {
return this.followed.containsKey(pack.resolve(path).toAbsolutePath().normalize());
}

private void start() throws IOException {
this.watcher = FileSystems.getDefault().newWatchService();
this.settle = Executors.newSingleThreadScheduledExecutor(runnable -> {
Thread thread = new Thread(runnable, "TotalDebug external edits");
thread.setDaemon(true);
return thread;
});
WatchService watching = this.watcher;
Thread thread = new Thread(() -> watch(watching), "TotalDebug external edit watcher");
thread.setDaemon(true);
thread.start();
}

private void watch(WatchService watching) {
while (true) {
WatchKey key;
try {
key = watching.take();
} catch (InterruptedException | ClosedWatchServiceException stopped) {
return;
}
Path folder = (Path) key.watchable();
for (WatchEvent<?> event : key.pollEvents()) {
if (event.kind() == StandardWatchEventKinds.OVERFLOW) {
// Which files changed is lost: every followed file of the folder is looked at.
this.followed.forEach((file, followedFile) -> {
if (file.getParent().equals(folder)) settle(followedFile);
});
} else if (event.context() instanceof Path name) {
Followed file = this.followed.get(folder.resolve(name));
if (file != null) settle(file);
}
}
if (!key.reset()) this.folders.remove(folder);
}
private synchronized void stopFollowing(Path file) {
Followed followed = this.followed.remove(file);
if (followed == null) return;
followed.unwatch.run();
if (followed.pending != null) followed.pending.cancel(false);
}

/** Takes the file once it stayed unchanged for a moment. */
private synchronized void settle(Followed file) {
if (this.closed) return;
if (file.pending != null) file.pending.cancel(false);
file.pending = this.settle.schedule(() -> take(file), SETTLE_MILLIS, TimeUnit.MILLISECONDS);
long write = ++file.writes;
file.pending = Workers.later(SETTLE_MILLIS, this.strand, () -> take(file, write));
}

private void take(Followed file) {
private void take(Followed file, long write) {
synchronized (this) {
// Another write came since, whose own settle takes the file.
if (this.closed || write != file.writes) return;
Comment on lines +133 to +135

@chatgpt-codex-connector chatgpt-codex-connector Bot Sep 30, 2026

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P2 Badge Revalidate the take after reading the file

If a later write event or project close occurs after this check but while Files.readAllBytes is in progress, as can happen with a large or slow resource, the task still calls adopt with content its generation no longer owns; non-PNG partial bytes can consequently be recorded and reloaded, and an in-flight take can survive close(). The fresh race remains after the queued-task fix because validation occurs only before the blocking read; recheck closed and write == file.writes after reading, as FileReading.readHere does before publishing.

AGENTS.md reference: AGENTS.md:L19-L19

Useful? React with 👍 / 👎.

}
Path location = file.pack.resolve(file.path);
byte[] seen;
try {
Expand All @@ -177,7 +145,12 @@ private void take(Followed file) {
// Still being written; the program's next write comes as another event.
return;
}
this.edits.adopt(file.path, file.pack, file.before, seen).whenComplete((saved, failure) -> {
CompletableFuture<ResourceEdits.Saved> adopted;
synchronized (this) {
if (this.closed || write != file.writes) return;
adopted = this.edits.adopt(file.path, file.pack, file.before, seen);
}
adopted.whenComplete((saved, failure) -> {
if (saved == null && failure == null) return;
Throwable cause = failure instanceof CompletionException && failure.getCause() != null ? failure.getCause() : failure;
file.listeners.forEach(listener -> listener.accept(saved, cause));
Expand Down Expand Up @@ -234,21 +207,12 @@ public CompletableFuture<Void> openLater(String path, Path pack, String program)
} catch (IOException exception) {
throw new CompletionException(exception);
}
});
}, Workers.files());
}

@Override
public synchronized void close() {
this.closed = true;
this.followed.clear();
this.folders.clear();
if (this.settle != null) this.settle.shutdownNow();
if (this.watcher != null) {
try {
this.watcher.close();
} catch (IOException ignored) {
// Closing only stops the watch.
}
}
List.copyOf(this.followed.keySet()).forEach(this::stopFollowing);
}
}
4 changes: 2 additions & 2 deletions ...ub/minecraft_ta/totalDebugCompanion/ui/components/treeView/DecompiledSourcesTreeItem.java
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Original file line number Diff line number Diff line change
@@ -1,10 +1,10 @@
package com.github.minecraft_ta.totalDebugCompanion.ui.components.treeView;

import com.github.minecraft_ta.totalDebugCompanion.util.FileWatch;
import com.github.minecraft_ta.totalDebugCompanion.Icons;
import com.github.minecraft_ta.totalDebugCompanion.decompile.CompanionDecompilationService;
import com.github.minecraft_ta.totalDebugCompanion.ui.components.treeView.lazyFileTree.*;
import com.github.minecraft_ta.totalDebugCompanion.ui.presentation.PrimarySecondaryText;
import com.github.minecraft_ta.totalDebugCompanion.util.FileUtils;

import java.io.IOException;
import java.io.UncheckedIOException;
Expand All @@ -19,7 +19,7 @@ final class DecompiledSourcesTreeItem extends DirectoryTreeItem {
super("decompiled-files");
this.service = service;
setIcon(Icons.FOLDER);
this.stopWatching = FileUtils.startNewDirectoryWatcher(service.cacheDirectory(),
this.stopWatching = FileWatch.shared().watchEntries(service.cacheDirectory(),
() -> tree.loadItemsForTopLevelItem(this));
}

Expand Down
4 changes: 2 additions & 2 deletions ...com/github/minecraft_ta/totalDebugCompanion/ui/components/treeView/ScriptFileActions.java
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
package com.github.minecraft_ta.totalDebugCompanion.ui.components.treeView;

import com.github.minecraft_ta.totalDebugCompanion.util.FileWatch;
import com.github.minecraft_ta.totalDebugCompanion.notification.NotificationCenter.Source;
import com.github.minecraft_ta.totalDebugCompanion.notification.NotificationCenter.Severity;
import com.formdev.flatlaf.util.SystemFileChooser;
Expand All @@ -19,7 +20,6 @@
import com.github.minecraft_ta.totalDebugCompanion.ui.components.treeView.lazyFileTree.FileSystemFileItem;
import com.github.minecraft_ta.totalDebugCompanion.ui.components.treeView.lazyFileTree.LazyTreeNode;
import com.github.minecraft_ta.totalDebugCompanion.ui.views.FileNamePopup;
import com.github.minecraft_ta.totalDebugCompanion.util.FileUtils;

import javax.swing.*;
import javax.swing.tree.TreePath;
Expand Down Expand Up @@ -373,7 +373,7 @@ private CompletableFuture<Void> execute(List<Path> roots, boolean deleting, Work
ctx.project().requireActive();
for (Path root : roots) ctx.project().scriptFiles().mutable(root);
for (var entry : drafts.entrySet()) { entry.getKey().pendingSave().join(); entry.getKey().persist(entry.getValue()); saved.add(entry.getKey()); }
FileUtils.withPausedDirectoryWatchers(roots, () -> work.run(ctx.project().scriptFiles(), changes));
FileWatch.shared().pausing(roots, () -> work.run(ctx.project().scriptFiles(), changes));
} catch (IOException failure) { throw new CompletionException(failure); }
finally {
if (deleting) {
Expand Down
4 changes: 2 additions & 2 deletions ...t_ta/totalDebugCompanion/ui/components/treeView/lazyFileTree/FileSystemDirectoryItem.java
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Original file line number Diff line number Diff line change
@@ -1,8 +1,8 @@
package com.github.minecraft_ta.totalDebugCompanion.ui.components.treeView.lazyFileTree;

import com.github.minecraft_ta.totalDebugCompanion.util.FileWatch;
import com.github.minecraft_ta.totalDebugCompanion.ui.Tooltip;
import com.github.minecraft_ta.totalDebugCompanion.Icons;
import com.github.minecraft_ta.totalDebugCompanion.util.FileUtils;

import javax.swing.*;
import java.io.IOException;
Expand Down Expand Up @@ -34,7 +34,7 @@ public class FileSystemDirectoryItem extends DirectoryTreeItem {
setIcon(Icons.FOLDER);

this.stopWatching = watch
? FileUtils.startNewDirectoryWatcher(path, () -> {
? FileWatch.shared().watchEntries(path, () -> {

@chatgpt-codex-connector chatgpt-codex-connector Bot Sep 30, 2026

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P2 Badge Preserve recovery for linked tree directories

When a displayed directory is a symlink or Windows junction and its target is deleted and later recreated, this migration leaves the tree stale. After the target's watch key becomes invalid, FileWatch.place tests the logical link path, finds it is no longer a directory, and watches the link's parent; recreating the target changes only the target's parent, so no event reattaches the watch or clears the tree's error state. The former FileUtils registration resolved and retried the real target path, while createChildIfPresent deliberately admits linked directories, so FileWatch needs to preserve recovery through the real target before this consumer moves to it.

AGENTS.md reference: AGENTS.md:L19-L19

Useful? React with 👍 / 👎.

changed = true;
SwingUtilities.invokeLater(() -> lazyFileJTree.refreshDirectory(path));
})
Expand Down
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