* This method should be invoked before the file is accessed. * - * @param path + * @param file * the path to remember meta data for. The path's current status * information is saved. */ - protected FileSnapshot(File path) { - this(path, true); + protected FileSnapshot(File file) { + this(file, true); } /** @@ -206,30 +213,35 @@ protected FileSnapshot(File path) { *
* This method should be invoked before the file is accessed. * - * @param path + * @param file * the path to remember meta data for. The path's current status * information is saved. * @param useConfig * if {@code true} read filesystem time resolution from * configuration file otherwise use fallback resolution */ - protected FileSnapshot(File path, boolean useConfig) { + protected FileSnapshot(File file, boolean useConfig) { + this.file = file; this.lastRead = System.currentTimeMillis(); this.fsTimestampResolution = useConfig - ? FS.getFsTimerResolution(path.toPath().getParent()) + ? FS.getFsTimerResolution(file.toPath().getParent()) : FALLBACK_TIMESTAMP_RESOLUTION; BasicFileAttributes fileAttributes = null; try { - fileAttributes = FS.DETECTED.fileAttributes(path); + fileAttributes = FS.DETECTED.fileAttributes(file); } catch (IOException e) { - this.lastModified = path.lastModified(); - this.size = path.length(); + this.lastModified = file.lastModified(); + this.size = file.length(); this.fileKey = MISSING_FILEKEY; return; } this.lastModified = fileAttributes.lastModifiedTime().toMillis(); this.size = fileAttributes.size(); this.fileKey = getFileKey(fileAttributes); + LOG.debug("file={}, create new FileSnapshot: lastRead={} ms" //$NON-NLS-1$ + + ", lastModified={} ms, size={}, fileKey={}", //$NON-NLS-1$ + file, Long.valueOf(lastRead), Long.valueOf(lastModified), + Long.valueOf(size), fileKey); } private boolean sizeChanged; @@ -242,6 +254,7 @@ protected FileSnapshot(File path, boolean useConfig) { private FileSnapshot(long read, long modified, long size, @NonNull Duration fsTimestampResolution, @NonNull Object fileKey) { + this.file = null; this.lastRead = read; this.lastModified = modified; this.fsTimestampResolution = fsTimestampResolution; @@ -432,7 +445,14 @@ public String toString() { private boolean isRacyClean(long read) { // add a 10% safety margin long racyNanos = (fsTimestampResolution.toNanos() + 1) * 11 / 10; - return wasRacyClean = (read - lastModified) * 1_000_000 <= racyNanos; + long delta = (read - lastModified) * 1_000_000; + wasRacyClean = delta <= racyNanos; + LOG.debug("file={}, isRacyClean={}, read={} ms, lastModified={} ms," //$NON-NLS-1$ + + " delta={} ns, racy<={} ns", //$NON-NLS-1$ + file, Boolean.valueOf(wasRacyClean), Long.valueOf(read), + Long.valueOf(lastModified), Long.valueOf(delta), + Long.valueOf(racyNanos)); + return wasRacyClean; } private boolean isModified(long currLastModified) { @@ -440,6 +460,9 @@ private boolean isModified(long currLastModified) { lastModifiedChanged = lastModified != currLastModified; if (lastModifiedChanged) { + LOG.debug("file={}, lastModified changed from {} to {}", //$NON-NLS-1$ + file, Long.valueOf(lastModified), + Long.valueOf(currLastModified)); return true; } @@ -447,26 +470,40 @@ private boolean isModified(long currLastModified) { // after the last modification that any new modifications // are certain to change the last modified time. if (cannotBeRacilyClean) { + LOG.debug("file={}, cannot be racily clean", file); //$NON-NLS-1$ return false; } if (!isRacyClean(lastRead)) { // Our last read should have marked cannotBeRacilyClean, // but this thread may not have seen the change. The read // of the volatile field lastRead should have fixed that. + LOG.debug("file={}, is unmodified", file); //$NON-NLS-1$ return false; } // We last read this path too close to its last observed // modification time. We may have missed a modification. // Scan again, to ensure we still see the same state. + LOG.debug("file={}, is racily clean", file); //$NON-NLS-1$ return true; } private boolean isFileKeyChanged(Object currFileKey) { - return currFileKey != MISSING_FILEKEY && !currFileKey.equals(fileKey); + boolean changed = currFileKey != MISSING_FILEKEY + && !currFileKey.equals(fileKey); + if (changed) { + LOG.debug("file={}, FileKey changed from {} to {}", //$NON-NLS-1$ + file, fileKey, currFileKey); + } + return changed; } private boolean isSizeChanged(long currSize) { - return currSize != UNKNOWN_SIZE && currSize != size; + boolean changed = (currSize != UNKNOWN_SIZE) && (currSize != size); + if (changed) { + LOG.debug("file={}, size changed from {} to {} bytes", //$NON-NLS-1$ + file, Long.valueOf(size), Long.valueOf(currSize)); + } + return changed; } }