Files
niro-gen5w/weather/java/com/chaegeon/niro/WeatherRefreshCounters.java
T

65 lines
2.3 KiB
Java

package com.chaegeon.niro;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
/** Root-only, per-run E2E evidence. No request, location or secret is stored. */
final class WeatherRefreshCounters {
private final File directory;
private long signal;
private long callback;
WeatherRefreshCounters(File directory) throws IOException {
if (!directory.isDirectory()
|| !directory.getCanonicalPath().equals(directory.getAbsolutePath())) {
throw new IOException("invalid counter directory");
}
this.directory = directory;
writeAtomic("signal.counter", 0L);
writeAtomic("callback.counter", 0L);
}
synchronized void signalAccepted() throws IOException {
if (signal == Long.MAX_VALUE) {
throw new IOException("signal counter overflow");
}
writeAtomic("signal.counter", signal + 1L);
++signal;
}
synchronized void freshCallbackCompleted() throws IOException {
if (callback == Long.MAX_VALUE) {
throw new IOException("callback counter overflow");
}
writeAtomic("callback.counter", callback + 1L);
++callback;
}
private void writeAtomic(String name, long value) throws IOException {
File target = new File(directory, name);
File pending = new File(directory, name + ".new");
if (pending.exists() || !pending.getCanonicalPath().equals(pending.getAbsolutePath())
|| !target.getCanonicalPath().equals(target.getAbsolutePath())) {
throw new IOException("counter path not safe");
}
FileOutputStream output = new FileOutputStream(pending);
try {
if (!pending.setReadable(false, false)
|| !pending.setWritable(false, false)
|| !pending.setExecutable(false, false)
|| !pending.setReadable(true, true)
|| !pending.setWritable(true, true)) {
throw new IOException("counter permission failure");
}
output.write((Long.toString(value) + "\n").getBytes("US-ASCII"));
output.getFD().sync();
} finally {
output.close();
}
if (!pending.renameTo(target)) {
throw new IOException("counter replacement failed");
}
}
}