/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=4 sw=2 sts=2 et cin: */
/* 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 nsHttp_h__
#define nsHttp_h__

#include <stdint.h>
#include "prtime.h"
#include "nsString.h"
#include "nsError.h"
#include "nsTArray.h"
#include "mozilla/TimeStamp.h"
#include "mozilla/Tuple.h"
#include "mozilla/UniquePtr.h"

class nsICacheEntry;

namespace mozilla {

class Mutex;

namespace net {
class nsHttpResponseHead;
class nsHttpRequestHead;
class CacheControlParser;

enum class HttpVersion {
  UNKNOWN = 0,
  v0_9 = 9,
  v1_0 = 10,
  v1_1 = 11,
  v2_0 = 20,
  v3_0 = 30
};

enum class SpdyVersion { NONE = 0, HTTP_2 = 5 };

extern const uint32_t kHttp3VersionCount;
extern const nsCString kHttp3Versions[];

//-----------------------------------------------------------------------------
// http connection capabilities
//-----------------------------------------------------------------------------

#define NS_HTTP_ALLOW_KEEPALIVE (1 << 0)
#define NS_HTTP_LARGE_KEEPALIVE (1 << 1)

// a transaction with this caps flag will continue to own the connection,
// preventing it from being reclaimed, even after the transaction completes.
#define NS_HTTP_STICKY_CONNECTION (1 << 2)

// a transaction with this caps flag will, upon opening a new connection,
// bypass the local DNS cache
#define NS_HTTP_REFRESH_DNS (1 << 3)

// a transaction with this caps flag will not pass SSL client-certificates
// to the server (see bug #466080), but is may also be used for other things
#define NS_HTTP_LOAD_ANONYMOUS (1 << 4)

// a transaction with this caps flag keeps timing information
#define NS_HTTP_TIMING_ENABLED (1 << 5)

// a transaction with this flag blocks the initiation of other transactons
// in the same load group until it is complete
#define NS_HTTP_LOAD_AS_BLOCKING (1 << 6)

// Disallow the use of the SPDY protocol. This is meant for the contexts
// such as HTTP upgrade which are nonsensical for SPDY, it is not the
// SPDY configuration variable.
#define NS_HTTP_DISALLOW_SPDY (1 << 7)

// a transaction with this flag loads without respect to whether the load
// group is currently blocking on some resources
#define NS_HTTP_LOAD_UNBLOCKED (1 << 8)

// This flag indicates the transaction should accept associated pushes
#define NS_HTTP_ONPUSH_LISTENER (1 << 9)

// Transactions with this flag should react to errors without side effects
// First user is to prevent clearing of alt-svc cache on failed probe
#define NS_HTTP_ERROR_SOFTLY (1 << 10)

// This corresponds to nsIHttpChannelInternal.beConservative
// it disables any cutting edge features that we are worried might result in
// interop problems with critical infrastructure
#define NS_HTTP_BE_CONSERVATIVE (1 << 11)

// Transactions with this flag should be processed first.
#define NS_HTTP_URGENT_START (1 << 12)

// A sticky connection of the transaction is explicitly allowed to be restarted
// on ERROR_NET_RESET.
#define NS_HTTP_CONNECTION_RESTARTABLE (1 << 13)

// Allow re-using a spdy/http2 connection with NS_HTTP_ALLOW_KEEPALIVE not set.
// This is primarily used to allow connection sharing for websockets over http/2
// without accidentally allowing it for websockets not over http/2
#define NS_HTTP_ALLOW_SPDY_WITHOUT_KEEPALIVE (1 << 15)

// Only permit CONNECTing to a proxy. A channel with this flag will not send an
// http request after CONNECT or setup tls. An http upgrade handler MUST be
// set. An ALPN header is set using the upgrade protocol.
#define NS_HTTP_CONNECT_ONLY (1 << 16)

// The connection should not use IPv4.
#define NS_HTTP_DISABLE_IPV4 (1 << 17)

// The connection should not use IPv6
#define NS_HTTP_DISABLE_IPV6 (1 << 18)

// Encodes the TRR mode.
#define NS_HTTP_TRR_MODE_MASK ((1 << 19) | (1 << 20))

// The connection could bring the peeked data for sniffing
#define NS_HTTP_CALL_CONTENT_SNIFFER (1 << 21)

// Disallow the use of the HTTP3 protocol. This is meant for the contexts
// such as HTTP upgrade which are not supported by HTTP3.
#define NS_HTTP_DISALLOW_HTTP3 (1 << 22)

// Force a transaction to stay in pending queue until the HTTPSSVC record is
// available.
#define NS_HTTP_WAIT_HTTPSSVC_RESULT (1 << 23)

#define NS_HTTP_TRR_FLAGS_FROM_MODE(x) ((static_cast<uint32_t>(x) & 3) << 19)

#define NS_HTTP_TRR_MODE_FROM_FLAGS(x) \
  (static_cast<nsIRequest::TRRMode>((((x)&NS_HTTP_TRR_MODE_MASK) >> 19) & 3))

//-----------------------------------------------------------------------------
// some default values
//-----------------------------------------------------------------------------

#define NS_HTTP_DEFAULT_PORT 80
#define NS_HTTPS_DEFAULT_PORT 443

#define NS_HTTP_HEADER_SEP ','

//-----------------------------------------------------------------------------
// http atoms...
//-----------------------------------------------------------------------------

struct nsHttpAtom {
  nsHttpAtom() : _val(nullptr){};
  explicit nsHttpAtom(const char* val) : _val(val) {}
  nsHttpAtom(const nsHttpAtom& other) = default;

  operator const char*() const { return _val; }
  const char* get() const { return _val; }

  void operator=(const char* v) { _val = v; }
  void operator=(const nsHttpAtom& a) { _val = a._val; }

  // private
  const char* _val;
};

namespace nsHttp {
[[nodiscard]] nsresult CreateAtomTable();
void DestroyAtomTable();

// The mutex is valid any time the Atom Table is valid
// This mutex is used in the unusual case that the network thread and
// main thread might access the same data
Mutex* GetLock();

// will dynamically add atoms to the table if they don't already exist
nsHttpAtom ResolveAtom(const char*);
inline nsHttpAtom ResolveAtom(const nsACString& s) {
  return ResolveAtom(PromiseFlatCString(s).get());
}

// returns true if the specified token [start,end) is valid per RFC 2616
// section 2.2
bool IsValidToken(const char* start, const char* end);

inline bool IsValidToken(const nsACString& s) {
  return IsValidToken(s.BeginReading(), s.EndReading());
}

// Strip the leading or trailing HTTP whitespace per fetch spec section 2.2.
void TrimHTTPWhitespace(const nsACString& aSource, nsACString& aDest);

// Returns true if the specified value is reasonable given the defintion
// in RFC 2616 section 4.2.  Full strict validation is not performed
// currently as it would require full parsing of the value.
bool IsReasonableHeaderValue(const nsACString& s);

// find the first instance (case-insensitive comparison) of the given
// |token| in the |input| string.  the |token| is bounded by elements of
// |separators| and may appear at the beginning or end of the |input|
// string.  null is returned if the |token| is not found.  |input| may be
// null, in which case null is returned.
const char* FindToken(const char* input, const char* token,
                      const char* separators);

// This function parses a string containing a decimal-valued, non-negative
// 64-bit integer.  If the value would exceed INT64_MAX, then false is
// returned.  Otherwise, this function returns true and stores the
// parsed value in |result|.  The next unparsed character in |input| is
// optionally returned via |next| if |next| is non-null.
//
// TODO(darin): Replace this with something generic.
//
[[nodiscard]] bool ParseInt64(const char* input, const char** next,
                              int64_t* result);

// Variant on ParseInt64 that expects the input string to contain nothing
// more than the value being parsed.
[[nodiscard]] inline bool ParseInt64(const char* input, int64_t* result) {
  const char* next;
  return ParseInt64(input, &next, result) && *next == '\0';
}

// Return whether the HTTP status code represents a permanent redirect
bool IsPermanentRedirect(uint32_t httpStatus);

// Returns the APLN token which represents the used protocol version.
const char* GetProtocolVersion(HttpVersion pv);

bool ValidationRequired(bool isForcedValid,
                        nsHttpResponseHead* cachedResponseHead,
                        uint32_t loadFlags, bool allowStaleCacheContent,
                        bool isImmutable, bool customConditionalRequest,
                        nsHttpRequestHead& requestHead, nsICacheEntry* entry,
                        CacheControlParser& cacheControlRequest,
                        bool fromPreviousSession,
                        bool* performBackgroundRevalidation = nullptr);

nsresult GetHttpResponseHeadFromCacheEntry(
    nsICacheEntry* entry, nsHttpResponseHead* cachedResponseHead);

nsresult CheckPartial(nsICacheEntry* aEntry, int64_t* aSize,
                      int64_t* aContentLength,
                      nsHttpResponseHead* responseHead);

void DetermineFramingAndImmutability(nsICacheEntry* entry,
                                     nsHttpResponseHead* cachedResponseHead,
                                     bool isHttps, bool* weaklyFramed,
                                     bool* isImmutable);

// Called when an optimization feature affecting active vs background tab load
// took place.  Called only on the parent process and only updates
// mLastActiveTabLoadOptimizationHit timestamp to now.
void NotifyActiveTabLoadOptimization();
TimeStamp const GetLastActiveTabLoadOptimizationHit();
void SetLastActiveTabLoadOptimizationHit(TimeStamp const& when);
bool IsBeforeLastActiveTabLoadOptimization(TimeStamp const& when);

// Declare all atoms
//
// The atom names and values are stored in nsHttpAtomList.h and are brought
// to you by the magic of C preprocessing.  Add new atoms to nsHttpAtomList
// and all support logic will be auto-generated.
//
#define HTTP_ATOM(_name, _value) extern nsHttpAtom _name;
#include "nsHttpAtomList.h"
#undef HTTP_ATOM

nsCString ConvertRequestHeadToString(nsHttpRequestHead& aRequestHead,
                                     bool aHasRequestBody,
                                     bool aRequestBodyHasHeaders,
                                     bool aUsingConnect);

template <typename T>
using SendFunc = std::function<bool(const T&, uint64_t, uint32_t)>;

template <typename T>
bool SendDataInChunks(const nsCString& aData, uint64_t aOffset, uint32_t aCount,
                      const SendFunc<T>& aSendFunc) {
  static uint32_t const kCopyChunkSize = 128 * 1024;
  uint32_t toRead = std::min<uint32_t>(aCount, kCopyChunkSize);

  uint32_t start = 0;
  while (aCount) {
    T data(Substring(aData, start, toRead));

    if (!aSendFunc(data, aOffset, toRead)) {
      return false;
    }

    aOffset += toRead;
    start += toRead;
    aCount -= toRead;
    toRead = std::min<uint32_t>(aCount, kCopyChunkSize);
  }

  return true;
}

}  // namespace nsHttp

//-----------------------------------------------------------------------------
// utilities...
//-----------------------------------------------------------------------------

static inline uint32_t PRTimeToSeconds(PRTime t_usec) {
  return uint32_t(t_usec / PR_USEC_PER_SEC);
}

#define NowInSeconds() PRTimeToSeconds(PR_Now())

// Round q-value to 2 decimal places; return 2 most significant digits as uint.
#define QVAL_TO_UINT(q) ((unsigned int)((q + 0.005) * 100.0))

#define HTTP_LWS " \t"
#define HTTP_HEADER_VALUE_SEPS HTTP_LWS ","

void EnsureBuffer(UniquePtr<char[]>& buf, uint32_t newSize, uint32_t preserve,
                  uint32_t& objSize);
void EnsureBuffer(UniquePtr<uint8_t[]>& buf, uint32_t newSize,
                  uint32_t preserve, uint32_t& objSize);

// h2=":443"; ma=60; single
// results in 3 mValues = {{h2, :443}, {ma, 60}, {single}}

class ParsedHeaderPair {
 public:
  ParsedHeaderPair(const char* name, int32_t nameLen, const char* val,
                   int32_t valLen, bool isQuotedValue);

  ParsedHeaderPair(ParsedHeaderPair const& copy)
      : mName(copy.mName),
        mValue(copy.mValue),
        mUnquotedValue(copy.mUnquotedValue),
        mIsQuotedValue(copy.mIsQuotedValue) {
    if (mIsQuotedValue) {
      mValue.Rebind(mUnquotedValue.BeginReading(), mUnquotedValue.Length());
    }
  }

  nsDependentCSubstring mName;
  nsDependentCSubstring mValue;

 private:
  nsCString mUnquotedValue;
  bool mIsQuotedValue;

  void RemoveQuotedStringEscapes(const char* val, int32_t valLen);
};

class ParsedHeaderValueList {
 public:
  ParsedHeaderValueList(const char* t, uint32_t len, bool allowInvalidValue);
  nsTArray<ParsedHeaderPair> mValues;

 private:
  void ParseNameAndValue(const char* input, bool allowInvalidValue);
};

class ParsedHeaderValueListList {
 public:
  // RFC 7231 section 3.2.6 defines the syntax of the header field values.
  // |allowInvalidValue| indicates whether the rule will be used to check
  // the input text.
  // Note that ParsedHeaderValueListList is currently used to parse
  // Alt-Svc and Server-Timing header. |allowInvalidValue| is set to true
  // when parsing Alt-Svc for historical reasons.
  explicit ParsedHeaderValueListList(const nsCString& txt,
                                     bool allowInvalidValue = true);
  nsTArray<ParsedHeaderValueList> mValues;

 private:
  nsCString mFull;
};

void LogHeaders(const char* lineStart);

// Convert HTTP response codes returned by a proxy to nsresult.
// This function should be only used when we get a failed response to the
// CONNECT method.
nsresult HttpProxyResponseToErrorCode(uint32_t aStatusCode);

// Given a list of alpn-id, this function returns a supported alpn-id. If both
// h3 and h2 are enabled, h3 alpn is preferred. This function returns a
// Tuple<alpn-id, isHttp3>. The first element is the alpn-id and the second one
// is a boolean to indicate if this alpn-id is for http3. If no supported
// alpn-id is found, the first element would be a n empty string.
Tuple<nsCString, bool> SelectAlpnFromAlpnList(
    const nsTArray<nsCString>& aAlpnList, bool aNoHttp2, bool aNoHttp3);

}  // namespace net
}  // namespace mozilla

#endif  // nsHttp_h__