/**
* Send files in response to request messages. The request sequence looks like the following:
*
* <p>[FileReq | StatReq]+ Done
*
* <p>The response sequence to a FileReq looks like:
*
* <p>FileStart <file byte stream> FileEnd
*
* <p>and that for a StatReq, is simply a StatResp
*/
private void sendRequestedFiles(Protocol protocol)
throws IOException, ProtocolException, DatabaseException {
try {
while (true) {
FileReq fileReq = protocol.read(namedChannel.getChannel(), FileReq.class);
final String fileName = fileReq.getFileName();
/*
* Calculate the full path for a specified log file name,
* especially when this Feeder is configured to run with sub
* directories.
*/
FileManager fMgr = feederManager.getEnvImpl().getFileManager();
File file = new File(fMgr.getFullFileName(fileName));
if (!file.exists()) {
throw EnvironmentFailureException.unexpectedState("Log file not found: " + fileName);
}
/* Freeze the length and last modified date. */
final long length = file.length();
final long lastModified = file.lastModified();
byte digest[] = null;
FileInfoResp resp = null;
Protocol.FileInfoResp cachedResp = feederManager.statResponses.get(fileName);
byte cachedDigest[] =
((cachedResp != null)
&& (cachedResp.getFileLength() == length)
&& (cachedResp.getLastModifiedTime() == lastModified))
? cachedResp.getDigestSHA1()
: null;
if (fileReq instanceof FileInfoReq) {
if (cachedDigest != null) {
digest = cachedDigest;
} else if (((FileInfoReq) fileReq).getNeedSHA1()) {
digest = getSHA1Digest(file, length).digest();
} else {
// Digest not requested
digest = new byte[0];
}
resp = protocol.new FileInfoResp(fileName, length, lastModified, digest);
} else {
protocol.write(protocol.new FileStart(fileName, length, lastModified), namedChannel);
digest = sendFileContents(file, length);
if ((cachedDigest != null) && !Arrays.equals(cachedDigest, digest)) {
throw EnvironmentFailureException.unexpectedState(
"Inconsistent cached and computed digests");
}
resp = protocol.new FileEnd(fileName, length, lastModified, digest);
}
/* Cache for subsequent requests, if it was computed. */
if (digest.length > 0) {
feederManager.statResponses.put(fileName, resp);
}
protocol.write(resp, namedChannel);
}
} catch (ProtocolException pe) {
if (pe.getUnexpectedMessage() instanceof Protocol.Done) {
return;
}
throw pe;
}
}
