QNAM: Direct transfer of HTTP buffer to the QNetworkReply buffer

Directly put a QRingBuffer from one QRingBuffer to
another QRingBuffer.

Reviewed-by: Thiago Macieira

5 files changed, 62 insertions, 13 deletions

diff --git a/src/corelib/tools/qringbuffer_p.h b/src/corelib/tools/qringbuffer_p.h
index b8e08ac..f3daca7 100644
--- a/src/corelib/tools/qringbuffer_p.h
+++ b/src/corelib/tools/qringbuffer_p.h
@@ -301,6 +301,51 @@ public:
         return read(size());
     }
 
+    // read an unspecified amount (will read the first buffer)
+    inline QByteArray read() {
+        // multiple buffers, just take the first one
+        if (head == 0 && tailBuffer != 0) {
+            QByteArray qba = buffers.takeFirst();
+            --tailBuffer;
+            bufferSize -= qba.length();
+            return qba;
+        }
+
+        // one buffer with good value for head. Just take it.
+        if (head == 0 && tailBuffer == 0) {
+            QByteArray qba = buffers.takeFirst();
+            qba.resize(tail);
+            buffers << QByteArray();
+            bufferSize = 0;
+            tail = 0;
+            return qba;
+        }
+
+        // Bad case: We have to memcpy.
+        // We can avoid by initializing the QRingBuffer with basicBlockSize of 0
+        // and only using this read() function.
+        QByteArray qba(readPointer(), nextDataBlockSize());
+        buffers.takeFirst();
+        head = 0;
+        if (tailBuffer == 0) {
+            buffers << QByteArray();
+            tail = 0;
+        } else {
+            --tailBuffer;
+        }
+        bufferSize -= qba.length();
+        return qba;        
+    }
+
+    // append a new buffer to the end
+    inline void append(const QByteArray &qba) {
+        buffers[tailBuffer].resize(tail);
+        buffers << qba;
+        ++tailBuffer;
+        tail = qba.length();
+        bufferSize += qba.length();
+    }
+
     inline QByteArray peek(int maxLength) const {
         int bytesToRead = qMin(size(), maxLength);
         if(maxLength <= 0)
@@ -355,7 +400,7 @@ public:
 private:
     QList<QByteArray> buffers;
     int head, tail;
-    int tailBuffer;
+    int tailBuffer; // always buffers.size() - 1
     int basicBlockSize;
     int bufferSize;
 };
diff --git a/src/network/access/qhttpnetworkreply.cpp b/src/network/access/qhttpnetworkreply.cpp
index 72aec99..483589b 100644
--- a/src/network/access/qhttpnetworkreply.cpp
+++ b/src/network/access/qhttpnetworkreply.cpp
@@ -185,6 +185,12 @@ QByteArray QHttpNetworkReply::read(qint64 maxSize)
     return data;
 }
 
+QByteArray QHttpNetworkReply::readAny()
+{
+    Q_D(QHttpNetworkReply);
+    return d->responseData.read();
+}
+
 bool QHttpNetworkReply::isFinished() const
 {
     return d_func()->state == QHttpNetworkReplyPrivate::AllDoneState;
@@ -196,7 +202,7 @@ QHttpNetworkReplyPrivate::QHttpNetworkReplyPrivate(const QUrl &newUrl)
     : QHttpNetworkHeaderPrivate(newUrl), state(NothingDoneState), statusCode(100),
       majorVersion(0), minorVersion(0), bodyLength(0), contentRead(0), totalProgress(0),
       currentChunkSize(0), currentChunkRead(0), connection(0), initInflate(false),
-      autoDecompress(false), requestIsPrepared(false)
+      autoDecompress(false), responseData(0), requestIsPrepared(false)
 {
 }
 
diff --git a/src/network/access/qhttpnetworkreply_p.h b/src/network/access/qhttpnetworkreply_p.h
index 26e1047..b86cfaa 100644
--- a/src/network/access/qhttpnetworkreply_p.h
+++ b/src/network/access/qhttpnetworkreply_p.h
@@ -123,6 +123,7 @@ public:
     qint64 bytesAvailable() const;
     qint64 bytesAvailableNextBlock() const;
     QByteArray read(qint64 maxSize = -1);
+    QByteArray readAny();
 
     bool isFinished() const;
 
diff --git a/src/network/access/qnetworkaccesshttpbackend.cpp b/src/network/access/qnetworkaccesshttpbackend.cpp
index 71808d4..db84e58 100644
--- a/src/network/access/qnetworkaccesshttpbackend.cpp
+++ b/src/network/access/qnetworkaccesshttpbackend.cpp
@@ -649,16 +649,14 @@ void QNetworkAccessHttpBackend::readFromHttp()
     if (!httpReply)
         return;
 
-    // We implement the download rate control
-    // Don't read from QHttpNetworkAccess more than QNetworkAccessBackend wants
-    // One of the two functions above will be called when we can read again
+    // We read possibly more than nextDownstreamBlockSize(), but
+    // this is not a critical thing since it is already in the
+    // memory anyway
 
-    qint64 bytesToRead = qBound<qint64>(0, httpReply->bytesAvailable(), nextDownstreamBlockSize());
-    if (!bytesToRead)
-        return;
-
-    QByteArray data = httpReply->read(bytesToRead);
-    writeDownstreamData(data);
+    while (httpReply->bytesAvailable() != 0 && nextDownstreamBlockSize() != 0) {
+        const QByteArray data = httpReply->readAny();
+        writeDownstreamData(data);
+    }
 }
 
 void QNetworkAccessHttpBackend::replyFinished()
diff --git a/src/network/access/qnetworkreplyimpl.cpp b/src/network/access/qnetworkreplyimpl.cpp
index 6eacdf1..de39970 100644
--- a/src/network/access/qnetworkreplyimpl.cpp
+++ b/src/network/access/qnetworkreplyimpl.cpp
@@ -393,8 +393,7 @@ void QNetworkReplyImplPrivate::appendDownstreamData(const QByteArray &data)
     if (!q->isOpen())
         return;
 
-    char *ptr = readBuffer.reserve(data.size());
-    memcpy(ptr, data.constData(), data.size());
+    readBuffer.append(data);
 
     if (cacheEnabled && !cacheSaveDevice) {
         // save the meta data