1 files changed, 152 insertions, 0 deletions
diff --git a/netwerk/streamconv/converters/nsUnknownDecoder.h b/netwerk/streamconv/converters/nsUnknownDecoder.h
new file mode 100644
index 0000000000..0df9df93ad
--- /dev/null
+++ b/netwerk/streamconv/converters/nsUnknownDecoder.h
@@ -0,0 +1,152 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 "nsIThreadRetargetableStreamListener.h"
+#include "nsIContentSniffer.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/Atomics.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 nsIThreadRetargetableStreamListener {
+ 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
+
+  // nsIThreadRetargetableStreamListener methods
+  NS_DECL_NSITHREADRETARGETABLESTREAMLISTENER
+
+  explicit nsUnknownDecoder(nsIStreamListener* aListener = nullptr);
+
+ protected:
+  virtual ~nsUnknownDecoder();
+
+  virtual void DetermineContentType(nsIRequest* aRequest);
+  nsresult FireListenerNotifications(nsIRequest* request, nsISupports* aCtxt);
+
+  class ConvertedStreamListener : public nsIStreamListener {
+   public:
+    explicit ConvertedStreamListener(nsUnknownDecoder* aDecoder);
+
+    NS_DECL_ISUPPORTS
+    NS_DECL_NSIREQUESTOBSERVER
+    NS_DECL_NSISTREAMLISTENER
+
+   private:
+    virtual ~ConvertedStreamListener() = default;
+    static nsresult AppendDataToString(nsIInputStream* inputStream,
+                                       void* closure, const char* rawSegment,
+                                       uint32_t toOffset, uint32_t count,
+                                       uint32_t* writeCount);
+    nsUnknownDecoder* mDecoder;
+  };
+
+ protected:
+  nsCOMPtr<nsIStreamListener> mNextListener;
+
+  // Various sniffer functions.  Returning true means that a type
+  // was determined; false means no luck.
+  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 {
+    using TypeSniffFunc = bool (nsUnknownDecoder::*)(nsIRequest*);
+
+    const char* mBytes;
+    uint32_t 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, nullptr }
+
+#define SNIFFER_ENTRY_WITH_FUNC(_bytes, _func) \
+  { _bytes, sizeof(_bytes) - 1, nullptr, _func }
+
+  static nsSnifferEntry sSnifferEntries[];
+  static uint32_t sSnifferEntryNum;
+
+  // We guarantee in order delivery of OnStart, OnStop and OnData, therefore
+  // we do not need proper locking for mBuffer.
+  mozilla::Atomic<char*> mBuffer;
+  mozilla::Atomic<uint32_t> mBufferLen;
+
+  nsCString mContentType;
+
+  // This mutex syncs: mContentType, mDecodedData and mNextListener.
+  mutable mozilla::Mutex mMutex MOZ_UNANNOTATED;
+
+ protected:
+  nsresult ConvertEncodedData(nsIRequest* request, const char* data,
+                              uint32_t length);
+  nsCString mDecodedData;  // If data are encoded this will be uncompress data.
+};
+
+#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) override;
+};
+
+#endif /* nsUnknownDecoder_h__ */