From 66bd159dd34addfd8f787e14dc891359602f112c Mon Sep 17 00:00:00 2001
From: Andrew Kwon <andrewshky@gmail.com>
Date: Sun, 10 Jan 2021 22:28:01 -0800
Subject: [PATCH] Allow cancelling presence on remote nvim instances

- Add msgpack lib
- Restructure to have lib and deps folders
- Add cancellation methods and invoke remote cancellation on update
---
 lua/deps/msgpack.lua      | 509 ++++++++++++++++++++++++++++++++++++++
 lua/{ => deps}/struct.lua |   0
 lua/{ => lib}/log.lua     |   0
 lua/presence/discord.lua  |   2 +-
 lua/presence/init.lua     |  94 ++++++-
 5 files changed, 602 insertions(+), 3 deletions(-)
 create mode 100644 lua/deps/msgpack.lua
 rename lua/{ => deps}/struct.lua (100%)
 rename lua/{ => lib}/log.lua (100%)

diff --git a/lua/deps/msgpack.lua b/lua/deps/msgpack.lua
new file mode 100644
index 0000000..a4b928b
--- /dev/null
+++ b/lua/deps/msgpack.lua
@@ -0,0 +1,509 @@
+local table = require("table")
+local string = require("string")
+local luabit = require("bit")
+local tostr = string.char
+
+local double_decode_count = 0
+local double_encode_count = 0
+
+-- cache bitops
+local band, rshift = luabit.band, luabit.brshift
+if not rshift then -- luajit differ from luabit
+    rshift = luabit.rshift
+end
+
+local function byte_mod(x,v)
+    if x < 0 then
+        x = x + 256
+    end
+    return (x%v)
+end
+
+
+-- buffer
+local strbuf = "" -- for unpacking
+local strary = {} -- for packing
+
+local function strary_append_int16(n,h)
+    if n < 0 then
+        n = n + 65536
+    end
+    table.insert( strary, tostr(h, math.floor(n / 256), n % 256 ) )
+end
+
+local function strary_append_int32(n,h)
+    if n < 0 then
+        n = n  + 4294967296
+    end
+    table.insert(strary, tostr(h,
+        math.floor(n / 16777216),
+        math.floor(n / 65536) % 256,
+        math.floor(n / 256) % 256,
+    n % 256 ))
+end
+
+local doubleto8bytes
+local strary_append_double = function(n)
+    -- assume double
+    double_encode_count = double_encode_count + 1
+    local b = doubleto8bytes(n)
+    table.insert( strary, tostr(0xcb))
+    table.insert( strary, string.reverse(b) )   -- reverse: make big endian double precision
+end
+
+--- IEEE 754
+
+-- out little endian
+doubleto8bytes = function(x)
+    local function grab_byte(v)
+        return math.floor(v / 256), tostr(math.fmod(math.floor(v), 256))
+    end
+    local sign = 0
+    if x < 0 then sign = 1; x = -x end
+    local mantissa, exponent = math.frexp(x)
+    if x == 0 then -- zero
+        mantissa, exponent = 0, 0
+    elseif x == 1/0 then
+        mantissa, exponent = 0, 2047
+    else
+        mantissa = (mantissa * 2 - 1) * math.ldexp(0.5, 53)
+        exponent = exponent + 1022
+    end
+
+    local v, byte = "" -- convert to bytes
+    x = mantissa
+    for _ = 1,6 do
+        _, byte = grab_byte(x); v = v..byte -- 47:0
+    end
+    x, byte = grab_byte(exponent * 16 + x);  v = v..byte -- 55:48
+    x, byte = grab_byte(sign * 128 + x); v = v..byte -- 63:56
+    return v, x
+end
+
+local function bitstofrac(ary)
+    local x = 0
+    local cur = 0.5
+    for _, v in ipairs(ary) do
+        x = x + cur * v
+        cur = cur / 2
+    end
+    return x
+end
+
+local function bytestobits(ary)
+    local out={}
+    for _, v in ipairs(ary) do
+        for j = 0, 7, 1 do
+            table.insert(out, band( rshift(v,7-j), 1 ) )
+        end
+    end
+    return out
+end
+
+-- get little endian
+local function bytestodouble(v)
+    -- sign:1bit
+    -- exp: 11bit (2048, bias=1023)
+    local sign = math.floor(v:byte(8) / 128)
+    local exp = band( v:byte(8), 127 ) * 16 + rshift( v:byte(7), 4 ) - 1023 -- bias
+    -- frac: 52 bit
+    local fracbytes = {
+        band( v:byte(7), 15 ), v:byte(6), v:byte(5), v:byte(4), v:byte(3), v:byte(2), v:byte(1) -- big endian
+    }
+    local bits = bytestobits(fracbytes)
+
+    for _ = 1, 4 do table.remove(bits,1) end
+
+    if sign == 1 then sign = -1 else sign = 1 end
+
+    local frac = bitstofrac(bits)
+    if exp == -1023 and frac==0 then return 0 end
+    if exp == 1024 and frac==0 then return 1/0 *sign end
+
+    local real = math.ldexp(1+frac,exp)
+
+    return real * sign
+end
+
+--- packers
+
+local packers = {}
+
+packers.dynamic = function(data)
+    local t = type(data)
+    return packers[t](data)
+end
+
+packers["nil"] = function()
+    table.insert( strary, tostr(0xc0))
+end
+
+packers.boolean = function(data)
+    if data then -- pack true
+        table.insert( strary, tostr(0xc3))
+    else -- pack false
+        table.insert( strary, tostr(0xc2))
+    end
+end
+
+packers.number = function(n)
+    if math.floor(n) == n then -- integer
+        if n >= 0 then -- positive integer
+            if n < 128 then -- positive fixnum
+                table.insert( strary, tostr(n))
+            elseif n < 256 then -- uint8
+                table.insert(strary, tostr(0xcc,n))
+            elseif n < 65536 then -- uint16
+                strary_append_int16(n,0xcd)
+            elseif n < 4294967296 then -- uint32
+                strary_append_int32(n,0xce)
+            else -- lua cannot handle uint64, so double
+                strary_append_double(n)
+            end
+        else -- negative integer
+            if n >= -32 then -- negative fixnum
+                table.insert( strary, tostr( 0xe0 + ((n+256)%32)) )
+            elseif n >= -128 then -- int8
+                table.insert( strary, tostr(0xd0,byte_mod(n,0x100)))
+            elseif n >= -32768 then -- int16
+                strary_append_int16(n,0xd1)
+            elseif n >= -2147483648 then -- int32
+                strary_append_int32(n,0xd2)
+            else -- lua cannot handle int64, so double
+                strary_append_double(n)
+            end
+        end
+    else -- floating point
+        strary_append_double(n)
+    end
+end
+
+packers.string = function(data)
+    local n = #data
+    if n < 32 then
+        table.insert( strary, tostr( 0xa0+n ) )
+    elseif n < 65536 then
+        strary_append_int16(n,0xda)
+    elseif n < 4294967296 then
+        strary_append_int32(n,0xdb)
+    else
+        error("overflow")
+    end
+    table.insert( strary, data)
+end
+
+packers["function"] = function()
+    error("unimplemented:function")
+end
+
+packers.userdata = function()
+    error("unimplemented:userdata")
+end
+
+packers.thread = function()
+    error("unimplemented:thread")
+end
+
+packers.table = function(data)
+    local is_map,ndata,nmax = false,0,0
+    for k,_ in pairs(data) do
+        if type(k) == "number" then
+            if k > nmax then nmax = k end
+        else is_map = true end
+        ndata = ndata+1
+    end
+    if is_map then -- pack as map
+        if ndata < 16 then
+            table.insert( strary, tostr(0x80+ndata))
+        elseif ndata < 65536 then
+            strary_append_int16(ndata,0xde)
+        elseif ndata < 4294967296 then
+            strary_append_int32(ndata,0xdf)
+        else
+            error("overflow")
+        end
+        for k,v in pairs(data) do
+            packers[type(k)](k)
+            packers[type(v)](v)
+        end
+    else -- pack as array
+        if nmax < 16 then
+            table.insert( strary, tostr( 0x90+nmax ) )
+        elseif nmax < 65536 then
+            strary_append_int16(nmax,0xdc)
+        elseif nmax < 4294967296 then
+            strary_append_int32(nmax,0xdd)
+        else
+            error("overflow")
+        end
+        for i=1,nmax do packers[type(data[i])](data[i]) end
+    end
+end
+
+-- types decoding
+
+local types_map = {
+    [0xc0] = "nil",
+    [0xc2] = "false",
+    [0xc3] = "true",
+    [0xca] = "float",
+    [0xcb] = "double",
+    [0xcc] = "uint8",
+    [0xcd] = "uint16",
+    [0xce] = "uint32",
+    [0xcf] = "uint64",
+    [0xd0] = "int8",
+    [0xd1] = "int16",
+    [0xd2] = "int32",
+    [0xd3] = "int64",
+    [0xda] = "raw16",
+    [0xdb] = "raw32",
+    [0xdc] = "array16",
+    [0xdd] = "array32",
+    [0xde] = "map16",
+    [0xdf] = "map32",
+}
+
+local type_for = function(n)
+
+    if types_map[n] then return types_map[n]
+    elseif n < 0xc0 then
+        if n < 0x80 then return "fixnum_posi"
+        elseif n < 0x90 then return "fixmap"
+        elseif n < 0xa0 then return "fixarray"
+        else return "fixraw" end
+    elseif n > 0xdf then return "fixnum_neg"
+    else return "undefined" end
+end
+
+local types_len_map = {
+    uint16 = 2, uint32 = 4, uint64 = 8,
+    int16 = 2, int32 = 4, int64 = 8,
+    float = 4, double = 8,
+}
+
+
+
+
+--- unpackers
+
+local unpackers = {}
+
+local unpack_number = function(offset,ntype,nlen)
+    local b1,b2,b3,b4,b5,b6,b7,b8
+    if nlen>=2 then
+        b1,b2 = string.byte( strbuf, offset+1, offset+2 )
+    end
+    if nlen>=4 then
+        b3,b4 = string.byte( strbuf, offset+3, offset+4 )
+    end
+    if nlen>=8 then
+        b5,b6,b7,b8 = string.byte( strbuf, offset+5, offset+8 )
+    end
+
+    if ntype == "uint16_t" then
+        return b1 * 256 + b2
+    elseif ntype == "uint32_t" then
+        return b1*65536*256 + b2*65536 + b3 * 256 + b4
+    elseif ntype == "int16_t" then
+        local n = b1 * 256 + b2
+        local nn = (65536 - n)*-1
+        if nn == -65536 then nn = 0 end
+        return nn
+    elseif ntype == "int32_t" then
+        local n = b1*65536*256 + b2*65536 + b3 * 256 + b4
+        local nn = ( 4294967296 - n ) * -1
+        if nn == -4294967296 then nn = 0 end
+        return nn
+    elseif ntype == "double_t" then
+        local s = tostr(b8,b7,b6,b5,b4,b3,b2,b1)
+        double_decode_count = double_decode_count + 1
+        local n = bytestodouble( s )
+        return n
+    else
+        error("unpack_number: not impl:" .. ntype )
+    end
+end
+
+
+
+local function unpacker_number(offset)
+    local obj_type = type_for( string.byte( strbuf, offset+1, offset+1 ) )
+    local nlen = types_len_map[obj_type]
+    local ntype
+    if (obj_type == "float") then
+        error("float is not implemented")
+    else
+        ntype = obj_type .. "_t"
+    end
+    return offset+nlen+1,unpack_number(offset+1,ntype,nlen)
+end
+
+local function unpack_map(offset,n)
+    local r = {}
+    local k,v
+    for _ = 1, n do
+        offset,k = unpackers.dynamic(offset)
+        assert(offset)
+        offset,v = unpackers.dynamic(offset)
+        assert(offset)
+        r[k] = v
+    end
+    return offset,r
+end
+
+local function unpack_array(offset,n)
+    local r = {}
+    for i=1,n do
+        offset,r[i] = unpackers.dynamic(offset)
+        assert(offset)
+    end
+    return offset,r
+end
+
+function unpackers.dynamic(offset)
+    if offset >= #strbuf then error("need more data") end
+    local obj_type = type_for( string.byte( strbuf, offset+1, offset+1 ) )
+    return unpackers[obj_type](offset)
+end
+
+function unpackers.undefined()
+    error("unimplemented:undefined")
+end
+
+unpackers["nil"] = function(offset)
+    return offset+1,nil
+end
+
+unpackers["false"] = function(offset)
+    return offset+1,false
+end
+
+unpackers["true"] = function(offset)
+    return offset+1,true
+end
+
+unpackers.fixnum_posi = function(offset)
+    return offset+1, string.byte(strbuf, offset+1, offset+1)
+end
+
+unpackers.uint8 = function(offset)
+    return offset+2, string.byte(strbuf, offset+2, offset+2)
+end
+
+unpackers.uint16 = unpacker_number
+unpackers.uint32 = unpacker_number
+unpackers.uint64 = unpacker_number
+
+unpackers.fixnum_neg = function(offset)
+    -- alternative to cast below:
+    local n = string.byte( strbuf, offset+1, offset+1)
+    local nn = ( 256 - n ) * -1
+    return offset+1,  nn
+end
+
+unpackers.int8 = function(offset)
+    local i = string.byte( strbuf, offset+2, offset+2 )
+    if i > 127 then
+        i = (256 - i ) * -1
+    end
+    return offset+2, i
+end
+
+unpackers.int16 = unpacker_number
+unpackers.int32 = unpacker_number
+unpackers.int64 = unpacker_number
+
+unpackers.float = unpacker_number
+unpackers.double = unpacker_number
+
+unpackers.fixraw = function(offset)
+    local n = byte_mod( string.byte( strbuf, offset+1, offset+1) ,0x1f+1)
+    --  print("unpackers.fixraw: offset:", offset, "#buf:", #buf, "n:",n  )
+    local b
+    if ( #strbuf - 1 - offset ) < n then
+        error("require more data")
+    end
+
+    if n > 0 then
+        b = string.sub( strbuf, offset + 1 + 1, offset + 1 + 1 + n - 1 )
+    else
+        b = ""
+    end
+    return offset+n+1, b
+end
+
+unpackers.raw16 = function(offset)
+    local n = unpack_number(offset+1,"uint16_t",2)
+    if ( #strbuf - 1 - 2 - offset ) < n then
+        error("require more data")
+    end
+    local b = string.sub( strbuf, offset+1+1+2, offset+1 + 1+2 + n - 1 )
+    return offset+n+3, b
+end
+
+unpackers.raw32 = function(offset)
+    local n = unpack_number(offset+1,"uint32_t",4)
+    if ( #strbuf  - 1 - 4 - offset ) < n then
+        error( "require more data (possibly bug)")
+    end
+    local b = string.sub( strbuf, offset+1+ 1+4, offset+1 + 1+4 +n -1 )
+    return offset+n+5,b
+end
+
+unpackers.fixarray = function(offset)
+    return unpack_array( offset+1,byte_mod( string.byte( strbuf, offset+1,offset+1),0x0f+1))
+end
+
+unpackers.array16 = function(offset)
+    return unpack_array(offset+3,unpack_number(offset+1,"uint16_t",2))
+end
+
+unpackers.array32 = function(offset)
+    return unpack_array(offset+5,unpack_number(offset+1,"uint32_t",4))
+end
+
+unpackers.fixmap = function(offset)
+    return unpack_map(offset+1,byte_mod( string.byte( strbuf, offset+1,offset+1),0x0f+1))
+end
+
+unpackers.map16 = function(offset)
+    return unpack_map(offset+3,unpack_number(offset+1,"uint16_t",2))
+end
+
+unpackers.map32 = function(offset)
+    return unpack_map(offset+5,unpack_number(offset+1,"uint32_t",4))
+end
+
+-- Main functions
+
+local ljp_pack = function(data)
+    strary={}
+    packers.dynamic(data)
+    local s = table.concat(strary,"")
+    return s
+end
+
+local ljp_unpack = function(s,offset)
+    if offset == nil then offset = 0 end
+    if type(s) ~= "string" then return false,"invalid argument" end
+    local data
+    strbuf = s
+    offset,data = unpackers.dynamic(offset)
+    return offset,data
+end
+
+local function ljp_stat()
+    return {
+        double_decode_count = double_decode_count,
+        double_encode_count = double_encode_count
+    }
+end
+
+local msgpack = {
+    pack = ljp_pack,
+    unpack = ljp_unpack,
+    stat = ljp_stat
+}
+
+return msgpack
diff --git a/lua/struct.lua b/lua/deps/struct.lua
similarity index 100%
rename from lua/struct.lua
rename to lua/deps/struct.lua
diff --git a/lua/log.lua b/lua/lib/log.lua
similarity index 100%
rename from lua/log.lua
rename to lua/lib/log.lua
diff --git a/lua/presence/discord.lua b/lua/presence/discord.lua
index 3ce81ec..b159d49 100644
--- a/lua/presence/discord.lua
+++ b/lua/presence/discord.lua
@@ -15,7 +15,7 @@ Discord.events = {
     ERROR = "ERROR",
 }
 
-local struct = require("struct")
+local struct = require("deps.struct")
 
 -- Initialize a new Discord RPC client
 function Discord:new(options)
diff --git a/lua/presence/init.lua b/lua/presence/init.lua
index 1440c5b..5a52d63 100644
--- a/lua/presence/init.lua
+++ b/lua/presence/init.lua
@@ -1,7 +1,8 @@
 local Presence = {}
 
-local Log = require("log")
+local Log = require("lib.log")
 local files = require("presence.files")
+local msgpack = require("deps.msgpack")
 local DiscordRPC = require("presence.discord")
 
 function Presence:setup(options)
@@ -54,6 +55,57 @@ function Presence:setup(options)
     return self
 end
 
+-- Send a nil activity to unset the presence
+function Presence:cancel_presence()
+    self.log:debug("Nullifying Discord presence...")
+
+    if not self.discord:is_connected() then
+        return
+    end
+
+    self.discord:set_activity(nil, function(err)
+        if err then
+            self.log:error("Failed to set nil activity in Discord: "..err)
+            return
+        end
+
+        self.log:info("Sent nil activity to Discord")
+    end)
+end
+
+-- Send command to cancel the presence for all other remote Neovim instances
+function Presence:cancel_all_remote_presences()
+    self:get_nvim_socket_addrs(function(sockets)
+        for i = 1, #sockets do
+            local nvim_socket = sockets[i]
+
+            -- Skip if the nvim socket is the current instance
+            if nvim_socket ~= vim.v.servername then
+                local command = "lua package.loaded.presence:cancel_presence()"
+                self:call_remote_nvim_instance(nvim_socket, command)
+            end
+        end
+    end)
+end
+
+-- Call a command on a remote Neovim instance at the provided IPC path
+function Presence:call_remote_nvim_instance(ipc_path, command)
+    local remote_nvim_instance = vim.loop.new_pipe(true)
+
+    remote_nvim_instance:connect(ipc_path, function()
+        self.log:debug(string.format("Connected to remote nvim instance at %s", ipc_path))
+
+        local packed = msgpack.pack({ 0, 0, "nvim_command", { command } })
+
+        remote_nvim_instance:write(packed, function()
+            self.log:debug(string.format("Wrote to remote nvim instance: %s", ipc_path))
+
+            remote_nvim_instance:shutdown()
+            remote_nvim_instance:close()
+        end)
+    end)
+end
+
 -- Check and warn for duplicate user-defined options
 function Presence:check_dup_options(option)
     local g_variable = "presence_"..option
@@ -64,7 +116,6 @@ function Presence:check_dup_options(option)
 
         self.log:warn(warning_msg)
     end
-
 end
 
 function Presence:connect(on_done)
@@ -154,6 +205,42 @@ function Presence.get_file_extension(path)
     return path:match("^.+%.(.+)$")
 end
 
+-- Get all active local nvim unix domain socket addresses
+function Presence:get_nvim_socket_addrs(on_done)
+    -- TODO: Find a better way to get paths of remote Neovim sockets lol
+    local cmd = [[netstat -u | grep --color=never "nvim.*/0" | awk -F "[ :]+" '{print $9}' | uniq]]
+
+    local sockets = {}
+    local function handle_data(_, data)
+        if not data then return end
+
+        for i = 1, #data do
+            local socket = data[i]
+            if socket ~= "" and socket ~= vim.v.servername then
+                table.insert(sockets, socket)
+            end
+        end
+    end
+
+    local function handle_error(_, data)
+        if not data then return end
+
+        if data[1] ~= "" then
+            self.log:error(data[1])
+        end
+    end
+
+    local function handle_exit()
+        on_done(sockets)
+    end
+
+    vim.fn.jobstart(cmd, {
+        on_stdout = handle_data,
+        on_stderr = handle_error,
+        on_exit = handle_exit,
+    })
+end
+
 -- Wrap calls to Discord that require prior connection and authorization
 function Presence.discord_event(on_ready)
     return function(self, ...)
@@ -182,6 +269,9 @@ end
 function Presence:update_for_buffer(buffer)
     self.log:debug(string.format("Setting activity for %s...", buffer))
 
+    -- Send command to cancel presence for all remote Neovim instances
+    self:cancel_all_remote_presences()
+
     -- Parse vim buffer
     local filename = self.get_filename(buffer)
     local extension = self.get_file_extension(filename)