gecko/netwerk/streamconv/converters/nsUnknownDecoder.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2012-05-21 04:12:37 -07:00
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef nsUnknownDecoder_h__
#define nsUnknownDecoder_h__
#include "nsIStreamConverter.h"
#include "nsIChannel.h"
#include "nsIContentSniffer.h"
#include "nsCOMPtr.h"
#include "nsString.h"
#define NS_UNKNOWNDECODER_CID \
{ /* 7d7008a0-c49a-11d3-9b22-0080c7cb1080 */ \
0x7d7008a0, \
0xc49a, \
0x11d3, \
{0x9b, 0x22, 0x00, 0x80, 0xc7, 0xcb, 0x10, 0x80} \
}
class nsUnknownDecoder : public nsIStreamConverter, public nsIContentSniffer
{
public:
// nsISupports methods
NS_DECL_ISUPPORTS
// nsIStreamConverter methods
NS_DECL_NSISTREAMCONVERTER
// nsIStreamListener methods
NS_DECL_NSISTREAMLISTENER
// nsIRequestObserver methods
NS_DECL_NSIREQUESTOBSERVER
// nsIContentSniffer methods
NS_DECL_NSICONTENTSNIFFER
nsUnknownDecoder();
protected:
virtual ~nsUnknownDecoder();
virtual void DetermineContentType(nsIRequest* aRequest);
nsresult FireListenerNotifications(nsIRequest* request, nsISupports *aCtxt);
protected:
nsCOMPtr<nsIStreamListener> mNextListener;
// Function to use to check whether sniffing some potentially
// dangerous types (eg HTML) is ok for this request. We can disable
// sniffing for local files if needed using this. Just a security
// precation thingy... who knows when we suddenly need to flip this
// pref?
bool AllowSniffing(nsIRequest* aRequest);
// Various sniffer functions. Returning true means that a type
// was determined; false means no luck.
bool TryContentSniffers(nsIRequest* aRequest);
bool SniffForHTML(nsIRequest* aRequest);
bool SniffForXML(nsIRequest* aRequest);
// SniffURI guesses at the content type based on the URI (typically
// using the extentsion)
bool SniffURI(nsIRequest* aRequest);
// LastDitchSniff guesses at text/plain vs. application/octet-stream
// by just looking at whether the data contains null bytes, and
// maybe at the fraction of chars with high bit set. Use this only
// as a last-ditch attempt to decide a content type!
bool LastDitchSniff(nsIRequest* aRequest);
/**
* An entry struct for our array of sniffers. Each entry has either
* a type associated with it (set these with the SNIFFER_ENTRY macro)
* or a function to be executed (set these with the
* SNIFFER_ENTRY_WITH_FUNC macro). The function should take a single
* nsIRequest* and returns bool -- true if it sets mContentType,
* false otherwise
*/
struct nsSnifferEntry {
typedef bool (nsUnknownDecoder::*TypeSniffFunc)(nsIRequest* aRequest);
const char* mBytes;
PRUint32 mByteLen;
// Exactly one of mMimeType and mContentTypeSniffer should be set non-null
const char* mMimeType;
TypeSniffFunc mContentTypeSniffer;
};
#define SNIFFER_ENTRY(_bytes, _type) \
{ _bytes, sizeof(_bytes) - 1, _type, nsnull }
#define SNIFFER_ENTRY_WITH_FUNC(_bytes, _func) \
{ _bytes, sizeof(_bytes) - 1, nsnull, _func }
static nsSnifferEntry sSnifferEntries[];
static PRUint32 sSnifferEntryNum;
char *mBuffer;
PRUint32 mBufferLen;
bool mRequireHTMLsuffix;
nsCString mContentType;
};
#define NS_BINARYDETECTOR_CID \
{ /* a2027ec6-ba0d-4c72-805d-148233f5f33c */ \
0xa2027ec6, \
0xba0d, \
0x4c72, \
{0x80, 0x5d, 0x14, 0x82, 0x33, 0xf5, 0xf3, 0x3c} \
}
/**
* Class that detects whether a data stream is text or binary. This reuses
* most of nsUnknownDecoder except the actual content-type determination logic
* -- our overridden DetermineContentType simply calls LastDitchSniff and sets
* the type to APPLICATION_GUESS_FROM_EXT if the data is detected as binary.
*/
class nsBinaryDetector : public nsUnknownDecoder
{
protected:
virtual void DetermineContentType(nsIRequest* aRequest);
};
#define NS_BINARYDETECTOR_CATEGORYENTRY \
{ NS_CONTENT_SNIFFER_CATEGORY, "Binary Detector", NS_BINARYDETECTOR_CONTRACTID }
#endif /* nsUnknownDecoder_h__ */