Make use of QDecompressHelper for HTTP downloads

Changes are not too big for now. Just replaces use of the previous
calls to the zlib decompression function. And initialize
QDecompressHelper when we know the content-encoding.

Task-number: QTBUG-83269
Change-Id: I41358feaef2e7ac5f48f14e3f95ec094e0c110b7
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

1 files changed, 26 insertions, 121 deletions

diff --git a/src/network/access/qhttpnetworkreply.cpp b/src/network/access/qhttpnetworkreply.cpp
index 66a431c5f9..e11ea401d2 100644
--- a/src/network/access/qhttpnetworkreply.cpp
+++ b/src/network/access/qhttpnetworkreply.cpp
@@ -46,10 +46,6 @@
 #    include <QtNetwork/qsslconfiguration.h>
 #endif
 
-#ifndef QT_NO_COMPRESS
-#include <zlib.h>
-#endif
-
 QT_BEGIN_NAMESPACE
 
 QHttpNetworkReply::QHttpNetworkReply(const QUrl &url, QObject *parent)
@@ -63,11 +59,6 @@ QHttpNetworkReply::~QHttpNetworkReply()
     if (d->connection) {
         d->connection->d_func()->removeReply(this);
     }
-
-#ifndef QT_NO_COMPRESS
-    if (d->autoDecompress && d->isCompressed() && d->inflateStrm)
-        inflateEnd(d->inflateStrm);
-#endif
 }
 
 QUrl QHttpNetworkReply::url() const
@@ -335,9 +326,6 @@ QHttpNetworkReplyPrivate::QHttpNetworkReplyPrivate(const QUrl &newUrl)
       autoDecompress(false), responseData(), requestIsPrepared(false)
       ,pipeliningUsed(false), h2Used(false), downstreamLimited(false)
       ,userProvidedDownloadBuffer(nullptr)
-#ifndef QT_NO_COMPRESS
-      ,inflateStrm(nullptr)
-#endif
 
 {
     QString scheme = newUrl.scheme();
@@ -347,13 +335,7 @@ QHttpNetworkReplyPrivate::QHttpNetworkReplyPrivate(const QUrl &newUrl)
         connectionCloseEnabled = false;
 }
 
-QHttpNetworkReplyPrivate::~QHttpNetworkReplyPrivate()
-{
-#ifndef QT_NO_COMPRESS
-      if (inflateStrm)
-          delete inflateStrm;
-#endif
-}
+QHttpNetworkReplyPrivate::~QHttpNetworkReplyPrivate() = default;
 
 void QHttpNetworkReplyPrivate::clearHttpLayerInformation()
 {
@@ -366,10 +348,7 @@ void QHttpNetworkReplyPrivate::clearHttpLayerInformation()
     currentChunkRead = 0;
     lastChunkRead = false;
     connectionCloseEnabled = true;
-#ifndef QT_NO_COMPRESS
-    if (autoDecompress && inflateStrm)
-        inflateEnd(inflateStrm);
-#endif
+    decompressHelper.clear();
     fields.clear();
 }
 
@@ -388,11 +367,15 @@ qint64 QHttpNetworkReplyPrivate::bytesAvailable() const
     return (state != ReadingDataState ? 0 : fragment.size());
 }
 
-bool QHttpNetworkReplyPrivate::isCompressed()
+bool QHttpNetworkReplyPrivate::isCompressed() const
+{
+    return QDecompressHelper::isSupportedEncoding(headerField("content-encoding"));
+}
+
+bool QHttpNetworkReply::isCompressed() const
 {
-    QByteArray encoding = headerField("content-encoding");
-    return encoding.compare("gzip", Qt::CaseInsensitive) == 0 ||
-            encoding.compare("deflate", Qt::CaseInsensitive) == 0;
+    Q_D(const QHttpNetworkReply);
+    return d->isCompressed();
 }
 
 void QHttpNetworkReplyPrivate::removeAutoDecompressHeader()
@@ -596,18 +579,10 @@ qint64 QHttpNetworkReplyPrivate::readHeader(QAbstractSocket *socket)
             headerField("proxy-connection").toLower().contains("close")) ||
             (majorVersion == 1 && minorVersion == 0 &&
             (connectionHeaderField.isEmpty() && !headerField("proxy-connection").toLower().contains("keep-alive")));
-
-#ifndef QT_NO_COMPRESS
         if (autoDecompress && isCompressed()) {
-            // allocate inflate state
-            if (!inflateStrm)
-                inflateStrm = new z_stream;
-            int ret = initializeInflateStream();
-            if (ret != Z_OK)
-                return -1;
+            if (!decompressHelper.setEncoding(headerField("content-encoding")))
+                return -1; // Either the encoding was unsupported or the decoder could not be set up
         }
-#endif
-
     }
     return bytes;
 }
@@ -709,12 +684,8 @@ qint64 QHttpNetworkReplyPrivate::readBody(QAbstractSocket *socket, QByteDataBuff
 {
     qint64 bytes = 0;
 
-#ifndef QT_NO_COMPRESS
-    // for gzip we'll allocate a temporary one that we then decompress
+    // for compressed data we'll allocate a temporary one that we then decompress
     QByteDataBuffer *tempOutDataBuffer = (autoDecompress ? new QByteDataBuffer : out);
-#else
-    QByteDataBuffer *tempOutDataBuffer = out;
-#endif
 
 
     if (isChunked()) {
@@ -730,94 +701,28 @@ qint64 QHttpNetworkReplyPrivate::readBody(QAbstractSocket *socket, QByteDataBuff
         bytes += readReplyBodyRaw(socket, tempOutDataBuffer, socket->bytesAvailable());
     }
 
-#ifndef QT_NO_COMPRESS
     // This is true if there is compressed encoding and we're supposed to use it.
     if (autoDecompress) {
-        qint64 uncompressRet = uncompressBodyData(tempOutDataBuffer, out);
-        delete tempOutDataBuffer;
-        if (uncompressRet < 0)
+        QScopedPointer holder(tempOutDataBuffer);
+        if (!decompressHelper.isValid())
             return -1;
-    }
-#endif
 
-    contentRead += bytes;
-    return bytes;
-}
-
-#ifndef QT_NO_COMPRESS
-int QHttpNetworkReplyPrivate::initializeInflateStream()
-{
-    Q_ASSERT(inflateStrm);
-
-    inflateStrm->zalloc = Z_NULL;
-    inflateStrm->zfree = Z_NULL;
-    inflateStrm->opaque = Z_NULL;
-    inflateStrm->avail_in = 0;
-    inflateStrm->next_in = Z_NULL;
-    // "windowBits can also be greater than 15 for optional gzip decoding.
-    // Add 32 to windowBits to enable zlib and gzip decoding with automatic header detection"
-    // http://www.zlib.net/manual.html
-    int ret = inflateInit2(inflateStrm, MAX_WBITS+32);
-    Q_ASSERT(ret == Z_OK);
-    return ret;
-}
-
-qint64 QHttpNetworkReplyPrivate::uncompressBodyData(QByteDataBuffer *in, QByteDataBuffer *out)
-{
-    if (!inflateStrm) { // happens when called from the SPDY protocol handler
-        inflateStrm = new z_stream;
-        initializeInflateStream();
-    }
-
-    if (!inflateStrm)
-        return -1;
-
-    bool triedRawDeflate = false;
-    for (int i = 0; i < in->bufferCount(); i++) {
-        QByteArray &bIn = (*in)[i];
-
-        inflateStrm->avail_in = bIn.size();
-        inflateStrm->next_in = reinterpret_cast<Bytef*>(bIn.data());
-
-        do {
-            QByteArray bOut;
-            // make a wild guess about the uncompressed size.
-            bOut.reserve(inflateStrm->avail_in * 3 + 512);
-            inflateStrm->avail_out = bOut.capacity();
-            inflateStrm->next_out = reinterpret_cast<Bytef*>(bOut.data());
-
-            int ret = inflate(inflateStrm, Z_NO_FLUSH);
-            //All negative return codes are errors, in the context of HTTP compression, Z_NEED_DICT is also an error.
-            // in the case where we get Z_DATA_ERROR this could be because we received raw deflate compressed data.
-            if (ret == Z_DATA_ERROR && !triedRawDeflate) {
-                inflateEnd(inflateStrm);
-                triedRawDeflate = true;
-                inflateStrm->zalloc = Z_NULL;
-                inflateStrm->zfree = Z_NULL;
-                inflateStrm->opaque = Z_NULL;
-                inflateStrm->avail_in = 0;
-                inflateStrm->next_in = Z_NULL;
-                int ret = inflateInit2(inflateStrm, -MAX_WBITS);
-                if (ret != Z_OK) {
-                    return -1;
-                } else {
-                    inflateStrm->avail_in = bIn.size();
-                    inflateStrm->next_in = reinterpret_cast<Bytef*>(bIn.data());
-                    continue;
-                }
-            } else if (ret < 0 || ret == Z_NEED_DICT) {
+        decompressHelper.feed(std::move(*tempOutDataBuffer));
+        while (decompressHelper.hasData()) {
+            QByteArray output(4 * 1024, Qt::Uninitialized);
+            qint64 read = decompressHelper.read(output.data(), output.size());
+            if (read < 0) {
                 return -1;
+            } else if (read > 0) {
+                output.resize(read);
+                out->append(std::move(output));
             }
-            bOut.resize(bOut.capacity() - inflateStrm->avail_out);
-            out->append(bOut);
-            if (ret == Z_STREAM_END)
-                return out->byteAmount();
-        } while (inflateStrm->avail_in > 0);
+        }
     }
 
-    return out->byteAmount();
+    contentRead += bytes;
+    return bytes;
 }
-#endif
 
 qint64 QHttpNetworkReplyPrivate::readReplyBodyRaw(QAbstractSocket *socket, QByteDataBuffer *out, qint64 size)
 {