On Mon, 12 Oct 2020 13:50:30 GMT, Daniel Fuchs <dfu...@openjdk.org> wrote:
>> Hi, >> >> This is a fix that upgrades the old HTTP and HTTPS legacy stack to use >> virtual-thread friendly locking instead of >> synchronized monitors. >> Most of the changes are mechanical - but there are still a numbers of subtle >> non-mechanical differences that are >> outlined below: >> 1. src/java.base/share/classes/sun/net/www/MessageHeader.java: >> `MessageHeader::print(PrintStream)` => synchronization modified to not >> synchronize on this while printing >> ( a snapshot of the data is taken before printing instead) >> >> 2. src/java.base/share/classes/sun/net/www/MeteredStream.java: >> `MeteredStream::close` was missing synchronization: it is now protected >> by the lock >> >> 3. src/java.base/share/classes/sun/net/www/http/ChunkedOutputStream.java: >> `ChunkedOutputStream` no longer extends `PrintStream` but extends >> `OutputStream` directly. >> Extending `PrintStream` is problematic for virtual thread. After careful >> analysis, it appeared that >> `ChunkedOutputStream` didn't really need to extend `PrintStream`. >> `ChunkedOutputStream` >> is already wrapping a `PrintStream`. `ChunkedOutputStream` is never >> returned directly to user >> code but is wrapped in another stream. `ChunkedOutputStream` completely >> reimplement and >> reverse the flush logic implemented by its old super class`PrintStream` >> which leads me to believe >> there was no real reason for it to extend `PrintStream` - except for >> being able to call its `checkError` >> method - which can be done by using `instanceof ChunkedOutputStream` in >> the caller instead of >> casting to PrintStream. >> >> 4. src/java.base/share/classes/sun/net/www/http/HttpClient.java: >> Synchronization removed from `HttpClient::privilegedOpenServer` and >> replaced by an `assert`. >> There is no need for a synchronized here as the method is only called >> from a method that already >> holds the lock. >> >> 5. src/java.base/share/classes/sun/net/www/http/KeepAliveCache.java: >> Synchronization removed from `KeepAliveCache::removeVector` and replaced >> by an `assert`. >> This method is only called from methods already protected by the lock. >> Also the method has been made private. >> >> 6. src/java.base/share/classes/sun/net/www/http/KeepAliveStream.java >> `queuedForCleanup` is made volatile as it is read and written directly >> from outside the class >> and without protection by the `KeepAliveCleanerEntry`. >> Lock protection is also added to `close()`, which was missing it. >> Some methods that have no lock protection and did not need it because >> only called from >> within code blocks protected by the lock have aquired an `assert >> isLockHeldByCurrentThread();` >> >> 7. Concrete subclasses of `AuthenticationInfo` that provide an >> implementation for >> `AuthenticationInfo::setHeaders(HttpURLConnection conn, HeaderParser p, >> String raw)` have >> acquired an `assert conn.isLockheldByCurrentThread();` as the method >> should only be called >> from within a lock-protected block in `s.n.w.p.h.HttpURLConnection` >> >> 8. >> src/java.base/share/classes/sun/net/www/protocol/http/HttpURLConnection.java >> Several methods in this class have a acquired an `assert >> isLockheldByCurrentThread();` >> to help track the fact that AuthenticationInfo::setHeaders is only >> called while >> holding the lock. >> Synchronization was also removed from some method that didn't need it >> because only >> called from within code blocks protected by the lock: >> `getOutputStream0()`: synchronization removed and replaced by an `assert >> isLockheldByCurrentThread();` >> `setCookieHeader()`: synchronization removed and replaced by an `assert >> isLockheldByCurrentThread();` >> `getInputStream0()`: synchronization removed and replaced by an `assert >> isLockheldByCurrentThread();` >> `StreamingOutputStream`: small change to accomodate point 3. above >> (changes in ChunkedOutputStream). >> >> 9. >> src/java.base/share/classes/sun/net/www/protocol/http/NegotiateAuthentication.java.: >> synchronization removed from `setHeaders` and replace by an assert. See >> point 7. above. >> >> 10. >> src/java.base/unix/classes/sun/net/www/protocol/http/ntlm/NTLMAuthentication.java: >> synchronization removed from `setHeaders` and replace by an assert. See >> point 7. above. >> >> 11. >> src/java.base/windows/classes/sun/net/www/protocol/http/ntlm/NTLMAuthentication.java: >> synchronization removed from `setHeaders` and replace by an assert. See >> point 7. above. > > Daniel Fuchs has updated the pull request with a new target base due to a > merge or a rebase. The incremental webrev > excludes the unrelated changes brought in by the merge/rebase. The pull > request contains four additional commits since > the last revision: > - 8229867: Re-examine synchronization usages in http and https protocol > handlers > > Incorporated review feedback > - Merge > - 8229867: Re-examine synchronization usages in http and https protocol > handlers > > Incorporated review feedback > - 8229867: Re-examine synchronization usages in http and https protocol > handlers LGTM. ------------- Marked as reviewed by chegar (Reviewer). PR: https://git.openjdk.java.net/jdk/pull/558
