+#define OPAQUETHREADBYTES 8
+
+/* a 64 bit opaque identifier */
+typedef unsigned char threadref[OPAQUETHREADBYTES];
+
+struct gdb_ext_thread_info;
+struct threads_listing_context;
+typedef int (*rmt_thread_action) (threadref *ref, void *context);
+struct protocol_feature;
+struct packet_reg;
+
+struct stop_reply;
+typedef std::unique_ptr<stop_reply> stop_reply_up;
+
+/* Generic configuration support for packets the stub optionally
+ supports. Allows the user to specify the use of the packet as well
+ as allowing GDB to auto-detect support in the remote stub. */
+
+enum packet_support
+ {
+ PACKET_SUPPORT_UNKNOWN = 0,
+ PACKET_ENABLE,
+ PACKET_DISABLE
+ };
+
+/* Analyze a packet's return value and update the packet config
+ accordingly. */
+
+enum packet_result
+{
+ PACKET_ERROR,
+ PACKET_OK,
+ PACKET_UNKNOWN
+};
+
+struct threads_listing_context;
+
+/* Stub vCont actions support.
+
+ Each field is a boolean flag indicating whether the stub reports
+ support for the corresponding action. */
+
+struct vCont_action_support
+{
+ /* vCont;t */
+ bool t = false;
+
+ /* vCont;r */
+ bool r = false;
+
+ /* vCont;s */
+ bool s = false;
+
+ /* vCont;S */
+ bool S = false;
+};
+
+/* About this many threadids fit in a packet. */
+
+#define MAXTHREADLISTRESULTS 32
+
+/* Data for the vFile:pread readahead cache. */
+
+struct readahead_cache
+{
+ /* Invalidate the readahead cache. */
+ void invalidate ();
+
+ /* Invalidate the readahead cache if it is holding data for FD. */
+ void invalidate_fd (int fd);
+
+ /* Serve pread from the readahead cache. Returns number of bytes
+ read, or 0 if the request can't be served from the cache. */
+ int pread (int fd, gdb_byte *read_buf, size_t len, ULONGEST offset);
+
+ /* The file descriptor for the file that is being cached. -1 if the
+ cache is invalid. */
+ int fd = -1;
+
+ /* The offset into the file that the cache buffer corresponds
+ to. */
+ ULONGEST offset = 0;
+
+ /* The buffer holding the cache contents. */
+ gdb_byte *buf = nullptr;
+ /* The buffer's size. We try to read as much as fits into a packet
+ at a time. */
+ size_t bufsize = 0;
+
+ /* Cache hit and miss counters. */
+ ULONGEST hit_count = 0;
+ ULONGEST miss_count = 0;
+};
+
+/* Description of the remote protocol for a given architecture. */
+
+struct packet_reg
+{
+ long offset; /* Offset into G packet. */
+ long regnum; /* GDB's internal register number. */
+ LONGEST pnum; /* Remote protocol register number. */
+ int in_g_packet; /* Always part of G packet. */
+ /* long size in bytes; == register_size (target_gdbarch (), regnum);
+ at present. */
+ /* char *name; == gdbarch_register_name (target_gdbarch (), regnum);
+ at present. */
+};
+
+struct remote_arch_state
+{
+ explicit remote_arch_state (struct gdbarch *gdbarch);
+
+ /* Description of the remote protocol registers. */
+ long sizeof_g_packet;
+
+ /* Description of the remote protocol registers indexed by REGNUM
+ (making an array gdbarch_num_regs in size). */
+ std::unique_ptr<packet_reg[]> regs;
+
+ /* This is the size (in chars) of the first response to the ``g''
+ packet. It is used as a heuristic when determining the maximum
+ size of memory-read and memory-write packets. A target will
+ typically only reserve a buffer large enough to hold the ``g''
+ packet. The size does not include packet overhead (headers and
+ trailers). */
+ long actual_register_packet_size;
+
+ /* This is the maximum size (in chars) of a non read/write packet.
+ It is also used as a cap on the size of read/write packets. */
+ long remote_packet_size;
+};
+
+/* Description of the remote protocol state for the currently
+ connected target. This is per-target state, and independent of the
+ selected architecture. */
+
+class remote_state
+{
+public:
+
+ remote_state ();
+ ~remote_state ();
+
+ /* Get the remote arch state for GDBARCH. */
+ struct remote_arch_state *get_remote_arch_state (struct gdbarch *gdbarch);
+
+public: /* data */
+
+ /* A buffer to use for incoming packets, and its current size. The
+ buffer is grown dynamically for larger incoming packets.
+ Outgoing packets may also be constructed in this buffer.
+ The size of the buffer is always at least REMOTE_PACKET_SIZE;
+ REMOTE_PACKET_SIZE should be used to limit the length of outgoing
+ packets. */
+ gdb::char_vector buf;
+
+ /* True if we're going through initial connection setup (finding out
+ about the remote side's threads, relocating symbols, etc.). */
+ bool starting_up = false;
+
+ /* If we negotiated packet size explicitly (and thus can bypass
+ heuristics for the largest packet size that will not overflow
+ a buffer in the stub), this will be set to that packet size.
+ Otherwise zero, meaning to use the guessed size. */
+ long explicit_packet_size = 0;
+
+ /* remote_wait is normally called when the target is running and
+ waits for a stop reply packet. But sometimes we need to call it
+ when the target is already stopped. We can send a "?" packet
+ and have remote_wait read the response. Or, if we already have
+ the response, we can stash it in BUF and tell remote_wait to
+ skip calling getpkt. This flag is set when BUF contains a
+ stop reply packet and the target is not waiting. */
+ int cached_wait_status = 0;
+
+ /* True, if in no ack mode. That is, neither GDB nor the stub will
+ expect acks from each other. The connection is assumed to be
+ reliable. */
+ bool noack_mode = false;
+
+ /* True if we're connected in extended remote mode. */
+ bool extended = false;
+
+ /* True if we resumed the target and we're waiting for the target to
+ stop. In the mean time, we can't start another command/query.
+ The remote server wouldn't be ready to process it, so we'd
+ timeout waiting for a reply that would never come and eventually
+ we'd close the connection. This can happen in asynchronous mode
+ because we allow GDB commands while the target is running. */
+ bool waiting_for_stop_reply = false;
+
+ /* The status of the stub support for the various vCont actions. */
+ vCont_action_support supports_vCont;
+ /* Whether vCont support was probed already. This is a workaround
+ until packet_support is per-connection. */
+ bool supports_vCont_probed;
+
+ /* True if the user has pressed Ctrl-C, but the target hasn't
+ responded to that. */
+ bool ctrlc_pending_p = false;
+
+ /* True if we saw a Ctrl-C while reading or writing from/to the
+ remote descriptor. At that point it is not safe to send a remote
+ interrupt packet, so we instead remember we saw the Ctrl-C and
+ process it once we're done with sending/receiving the current
+ packet, which should be shortly. If however that takes too long,
+ and the user presses Ctrl-C again, we offer to disconnect. */
+ bool got_ctrlc_during_io = false;
+
+ /* Descriptor for I/O to remote machine. Initialize it to NULL so that
+ remote_open knows that we don't have a file open when the program
+ starts. */
+ struct serial *remote_desc = nullptr;
+
+ /* These are the threads which we last sent to the remote system. The
+ TID member will be -1 for all or -2 for not sent yet. */
+ ptid_t general_thread = null_ptid;
+ ptid_t continue_thread = null_ptid;
+
+ /* This is the traceframe which we last selected on the remote system.
+ It will be -1 if no traceframe is selected. */
+ int remote_traceframe_number = -1;
+
+ char *last_pass_packet = nullptr;
+
+ /* The last QProgramSignals packet sent to the target. We bypass
+ sending a new program signals list down to the target if the new
+ packet is exactly the same as the last we sent. IOW, we only let
+ the target know about program signals list changes. */
+ char *last_program_signals_packet = nullptr;
+
+ gdb_signal last_sent_signal = GDB_SIGNAL_0;
+
+ bool last_sent_step = false;
+
+ /* The execution direction of the last resume we got. */
+ exec_direction_kind last_resume_exec_dir = EXEC_FORWARD;
+
+ char *finished_object = nullptr;
+ char *finished_annex = nullptr;
+ ULONGEST finished_offset = 0;
+
+ /* Should we try the 'ThreadInfo' query packet?
+
+ This variable (NOT available to the user: auto-detect only!)
+ determines whether GDB will use the new, simpler "ThreadInfo"
+ query or the older, more complex syntax for thread queries.
+ This is an auto-detect variable (set to true at each connect,
+ and set to false when the target fails to recognize it). */
+ bool use_threadinfo_query = false;
+ bool use_threadextra_query = false;
+
+ threadref echo_nextthread {};
+ threadref nextthread {};
+ threadref resultthreadlist[MAXTHREADLISTRESULTS] {};
+
+ /* The state of remote notification. */
+ struct remote_notif_state *notif_state = nullptr;
+
+ /* The branch trace configuration. */
+ struct btrace_config btrace_config {};
+
+ /* The argument to the last "vFile:setfs:" packet we sent, used
+ to avoid sending repeated unnecessary "vFile:setfs:" packets.
+ Initialized to -1 to indicate that no "vFile:setfs:" packet
+ has yet been sent. */
+ int fs_pid = -1;
+
+ /* A readahead cache for vFile:pread. Often, reading a binary
+ involves a sequence of small reads. E.g., when parsing an ELF
+ file. A readahead cache helps mostly the case of remote
+ debugging on a connection with higher latency, due to the
+ request/reply nature of the RSP. We only cache data for a single
+ file descriptor at a time. */
+ struct readahead_cache readahead_cache;
+
+ /* The list of already fetched and acknowledged stop events. This
+ queue is used for notification Stop, and other notifications
+ don't need queue for their events, because the notification
+ events of Stop can't be consumed immediately, so that events
+ should be queued first, and be consumed by remote_wait_{ns,as}
+ one per time. Other notifications can consume their events
+ immediately, so queue is not needed for them. */
+ std::vector<stop_reply_up> stop_reply_queue;
+
+ /* Asynchronous signal handle registered as event loop source for
+ when we have pending events ready to be passed to the core. */
+ struct async_event_handler *remote_async_inferior_event_token = nullptr;
+
+ /* FIXME: cagney/1999-09-23: Even though getpkt was called with
+ ``forever'' still use the normal timeout mechanism. This is
+ currently used by the ASYNC code to guarentee that target reads
+ during the initial connect always time-out. Once getpkt has been
+ modified to return a timeout indication and, in turn
+ remote_wait()/wait_for_inferior() have gained a timeout parameter
+ this can go away. */
+ int wait_forever_enabled_p = 1;
+
+private:
+ /* Mapping of remote protocol data for each gdbarch. Usually there
+ is only one entry here, though we may see more with stubs that
+ support multi-process. */
+ std::unordered_map<struct gdbarch *, remote_arch_state>
+ m_arch_states;
+};
+