Another attempt at solving the compression level change problems. We were still
not detecting the correct approach properly, and hence still getting crashes.
git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@4731 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/common/rdr/ZlibOutStream.cxx b/common/rdr/ZlibOutStream.cxx
index f04536f..260bd1a 100644
--- a/common/rdr/ZlibOutStream.cxx
+++ b/common/rdr/ZlibOutStream.cxx
@@ -23,27 +23,28 @@
#include <zlib.h>
+#undef ZLIBOUT_DEBUG
+
using namespace rdr;
enum { DEFAULT_BUF_SIZE = 16384 };
ZlibOutStream::ZlibOutStream(OutStream* os, int bufSize_, int compressLevel)
: underlying(os), compressionLevel(compressLevel), newLevel(compressLevel),
- bufSize(bufSize_ ? bufSize_ : DEFAULT_BUF_SIZE), offset(0),
- newBehavior(false)
+ bufSize(bufSize_ ? bufSize_ : DEFAULT_BUF_SIZE), offset(0)
{
zs = new z_stream;
zs->zalloc = Z_NULL;
zs->zfree = Z_NULL;
zs->opaque = Z_NULL;
+ zs->next_in = Z_NULL;
+ zs->avail_in = 0;
if (deflateInit(zs, compressLevel) != Z_OK) {
delete zs;
throw Exception("ZlibOutStream: deflateInit failed");
}
ptr = start = new U8[bufSize];
end = start + bufSize;
- const char *version = zlibVersion();
- if (strcmp(version, "1.2.3") > 0) newBehavior = true;
}
ZlibOutStream::~ZlibOutStream()
@@ -77,35 +78,17 @@
void ZlibOutStream::flush()
{
+ checkCompressionLevel();
+
zs->next_in = start;
zs->avail_in = ptr - start;
-// fprintf(stderr,"zos flush: avail_in %d\n",zs->avail_in);
+#ifdef ZLIBOUT_DEBUG
+ fprintf(stderr,"zos flush: avail_in %d\n",zs->avail_in);
+#endif
- if (!underlying)
- throw Exception("ZlibOutStream: underlying OutStream has not been set");
-
- while (zs->avail_in != 0) {
-
- do {
- underlying->check(1);
- zs->next_out = underlying->getptr();
- zs->avail_out = underlying->getend() - underlying->getptr();
-
-// fprintf(stderr,"zos flush: calling deflate, avail_in %d, avail_out %d\n",
-// zs->avail_in,zs->avail_out);
- checkCompressionLevel();
- if (zs->avail_in != 0) {
- int rc = deflate(zs, Z_SYNC_FLUSH);
- if (rc != Z_OK) throw Exception("ZlibOutStream: deflate failed");
- }
-
-// fprintf(stderr,"zos flush: after deflate: %d bytes\n",
-// zs->next_out-underlying->getptr());
-
- underlying->setptr(zs->next_out);
- } while (zs->avail_out == 0);
- }
+ // Force out everything from the zlib encoder
+ deflate(Z_SYNC_FLUSH);
offset += ptr - start;
ptr = start;
@@ -113,37 +96,20 @@
int ZlibOutStream::overrun(int itemSize, int nItems)
{
-// fprintf(stderr,"ZlibOutStream overrun\n");
+#ifdef ZLIBOUT_DEBUG
+ fprintf(stderr,"zos overrun\n");
+#endif
if (itemSize > bufSize)
throw Exception("ZlibOutStream overrun: max itemSize exceeded");
- if (!underlying)
- throw Exception("ZlibOutStream: underlying OutStream has not been set");
+ checkCompressionLevel();
while (end - ptr < itemSize) {
zs->next_in = start;
zs->avail_in = ptr - start;
- do {
- underlying->check(1);
- zs->next_out = underlying->getptr();
- zs->avail_out = underlying->getend() - underlying->getptr();
-
-// fprintf(stderr,"zos overrun: calling deflate, avail_in %d, avail_out %d\n",
-// zs->avail_in,zs->avail_out);
-
- checkCompressionLevel();
- if (zs->avail_in != 0) {
- int rc = deflate(zs, 0);
- if (rc != Z_OK) throw Exception("ZlibOutStream: deflate failed");
- }
-
-// fprintf(stderr,"zos overrun: after deflate: %d bytes\n",
-// zs->next_out-underlying->getptr());
-
- underlying->setptr(zs->next_out);
- } while (zs->avail_out == 0);
+ deflate(Z_NO_FLUSH);
// output buffer not full
@@ -166,23 +132,69 @@
return nItems;
}
+void ZlibOutStream::deflate(int flush)
+{
+ int rc;
+
+ if (!underlying)
+ throw Exception("ZlibOutStream: underlying OutStream has not been set");
+
+ if ((flush == Z_NO_FLUSH) && (zs->avail_in == 0))
+ return;
+
+ do {
+ underlying->check(1);
+ zs->next_out = underlying->getptr();
+ zs->avail_out = underlying->getend() - underlying->getptr();
+
+#ifdef ZLIBOUT_DEBUG
+ fprintf(stderr,"zos: calling deflate, avail_in %d, avail_out %d\n",
+ zs->avail_in,zs->avail_out);
+#endif
+
+ rc = ::deflate(zs, flush);
+ if (rc != Z_OK) {
+ // Silly zlib returns an error if you try to flush something twice
+ if ((rc == Z_BUF_ERROR) && (flush != Z_NO_FLUSH))
+ break;
+
+ throw Exception("ZlibOutStream: deflate failed");
+ }
+
+#ifdef ZLIBOUT_DEBUG
+ fprintf(stderr,"zos: after deflate: %d bytes\n",
+ zs->next_out-underlying->getptr());
+#endif
+
+ underlying->setptr(zs->next_out);
+ } while (zs->avail_out == 0);
+}
+
void ZlibOutStream::checkCompressionLevel()
{
+ int rc;
+
if (newLevel != compressionLevel) {
+#ifdef ZLIBOUT_DEBUG
+ fprintf(stderr,"zos change: avail_in %d\n",zs->avail_in);
+#endif
- // This is a horrible hack, but after many hours of trying, I couldn't find
- // a better way to make this class work properly with both Zlib 1.2.3 and
- // 1.2.5. 1.2.3 does a Z_PARTIAL_FLUSH in the body of deflateParams() if
- // the compression level has changed, and 1.2.5 does a Z_BLOCK flush.
+ // zlib is just horribly stupid. It does an implicit flush on
+ // parameter changes, but the flush it does is not one that forces
+ // out all the data. And since you cannot flush things again, we
+ // cannot force out our data after the parameter change. Hence we
+ // need to do a more proper flush here first.
+ deflate(Z_SYNC_FLUSH);
- if (newBehavior) {
- int rc = deflate(zs, Z_SYNC_FLUSH);
- if (rc != Z_OK) throw Exception("ZlibOutStream: deflate failed");
+ rc = deflateParams (zs, newLevel, Z_DEFAULT_STRATEGY);
+ if (rc != Z_OK) {
+ // The implicit flush can result in this error, caused by the
+ // explicit flush we did above. It should be safe to ignore though
+ // as the first flush should have left things in a stable state...
+ if (rc != Z_BUF_ERROR)
+ throw Exception("ZlibOutStream: deflateParams failed");
}
- if (deflateParams (zs, newLevel, Z_DEFAULT_STRATEGY) != Z_OK) {
- throw Exception("ZlibOutStream: deflateParams failed");
- }
compressionLevel = newLevel;
}
}
diff --git a/common/rdr/ZlibOutStream.h b/common/rdr/ZlibOutStream.h
index 250bb03..2d82a13 100644
--- a/common/rdr/ZlibOutStream.h
+++ b/common/rdr/ZlibOutStream.h
@@ -46,6 +46,7 @@
private:
int overrun(int itemSize, int nItems);
+ void deflate(int flush);
void checkCompressionLevel();
OutStream* underlying;
@@ -55,7 +56,6 @@
int offset;
z_stream_s* zs;
U8* start;
- bool newBehavior;
};
} // end of namespace rdr