channels: stderr channel

src/nvim/channel.c

@@ -14,6 +14,12 @@
 static bool did_stdio = false;
 PMap(uint64_t) *channels = NULL;
 
+/// next free id for a job or rpc channel
+/// 1 is reserved for stdio channel
+/// 2 is reserved for stderr channel
+static uint64_t next_chan_id = CHAN_STDERR+1;
+
+
 typedef struct {
   Channel *data;
   Callback *callback;
@@ -73,7 +79,6 @@ bool channel_close(uint64_t id, ChannelPart part, const char **error)
     }
   } else if ((part == kChannelPartStdin || part == kChannelPartStdout)
              && chan->is_rpc) {
-        // EMSG(_("Invalid stream on rpc job, use jobclose(id, 'rpc')"));
     *error = (const char *)e_invstreamrpc;
     return false;
   }
@@ -117,6 +122,21 @@ bool channel_close(uint64_t id, ChannelPart part, const char **error)
       }
       break;
 
+    case kChannelStreamStderr:
+      if (part != kChannelPartAll && part != kChannelPartStderr) {
+        *error = (const char *)e_invstream;
+        return false;
+      }
+      if (!chan->stream.err.closed) {
+        chan->stream.err.closed = true;
+        // Don't close on exit, in case late error messages
+        if (!exiting) {
+          fclose(stderr);
+        }
+        channel_decref(chan);
+      }
+      break;
+
     case kChannelStreamInternal:
       if (!close_main) {
         *error = (const char *)e_invstream;
@@ -132,6 +152,7 @@ bool channel_close(uint64_t id, ChannelPart part, const char **error)
 void channel_init(void)
 {
   channels = pmap_new(uint64_t)();
+  channel_alloc(kChannelStreamStderr);
   rpc_init();
   remote_ui_init();
 }
@@ -143,7 +164,13 @@ void channel_init(void)
 static Channel *channel_alloc(ChannelStreamType type)
 {
   Channel *chan = xcalloc(1, sizeof(*chan));
-  chan->id = type == kChannelStreamStdio ? 1 : next_chan_id++;
+  if (type == kChannelStreamStdio) {
+    chan->id = CHAN_STDIO;
+  } else if (type == kChannelStreamStderr) {
+    chan->id = CHAN_STDERR;
+  } else {
+    chan->id = next_chan_id++;
+  }
   chan->events = multiqueue_new_child(main_loop.events);
   chan->refcount = 1;
   chan->streamtype = type;
@@ -403,6 +430,46 @@ uint64_t channel_from_stdio(bool rpc, CallbackReader on_output,
   return channel->id;
 }
 
+/// @param data will be consumed
+size_t channel_send(uint64_t id, char *data, size_t len, const char **error)
+{
+  Channel *chan = find_channel(id);
+  if (!chan) {
+    EMSG(_(e_invchan));
+    goto err;
+  }
+
+  if (chan->streamtype == kChannelStreamStderr) {
+    if (chan->stream.err.closed) {
+      *error = _("Can't send data to closed stream");
+      goto err;
+    }
+    // unbuffered write
+    size_t written = fwrite(data, len, 1, stderr);
+    xfree(data);
+    return len * written;
+  }
+
+
+  Stream *in = channel_instream(chan);
+  if (in->closed) {
+    *error = _("Can't send data to closed stream");
+    goto err;
+  }
+
+  if (chan->is_rpc) {
+    *error = _("Can't send raw data to rpc channel");
+    goto err;
+  }
+
+  WBuffer *buf = wstream_new_buffer(data, len, 1, xfree);
+  return wstream_write(in, buf) ? len : 0;
+
+err:
+  xfree(data);
+  return 0;
+}
+
 // vimscript job callbacks must be executed on Nvim main loop
 static inline void process_channel_event(Channel *chan, Callback *callback,
                                          const char *type, char *buf,

src/nvim/channel.h

@@ -9,10 +9,14 @@
 #include "nvim/eval/typval.h"
 #include "nvim/msgpack_rpc/channel_defs.h"
 
+#define CHAN_STDIO 1
+#define CHAN_STDERR 2
+
 typedef enum {
   kChannelStreamProc,
   kChannelStreamSocket,
   kChannelStreamStdio,
+  kChannelStreamStderr,
   kChannelStreamInternal
 } ChannelStreamType;
 
@@ -30,6 +34,10 @@ typedef struct {
   Stream out;
 } StdioPair;
 
+typedef struct {
+  bool closed;
+} StderrState;
+
 typedef struct {
   Callback cb;
   garray_T buffer;
@@ -56,6 +64,7 @@ struct Channel {
     PtyProcess pty;
     Stream socket;
     StdioPair stdio;
+    StderrState err;
   } stream;
 
   bool is_rpc;
@@ -95,6 +104,7 @@ static inline Stream *channel_instream(Channel *chan)
       return &chan->stream.stdio.out;
 
     case kChannelStreamInternal:
+    case kChannelStreamStderr:
       abort();
   }
   abort();
@@ -114,6 +124,7 @@ static inline Stream *channel_outstream(Channel *chan)
       return &chan->stream.stdio.in;
 
     case kChannelStreamInternal:
+    case kChannelStreamStderr:
       abort();
   }
   abort();

src/nvim/eval.c

@@ -366,6 +366,7 @@ static struct vimvar {
   VV(VV_DYING,          "dying",            VAR_NUMBER, VV_RO),
   VV(VV_EXCEPTION,      "exception",        VAR_STRING, VV_RO),
   VV(VV_THROWPOINT,     "throwpoint",       VAR_STRING, VV_RO),
+  VV(VV_STDERR,         "stderr",           VAR_NUMBER, VV_RO),
   VV(VV_REG,            "register",         VAR_STRING, VV_RO),
   VV(VV_CMDBANG,        "cmdbang",          VAR_NUMBER, VV_RO),
   VV(VV_INSERTMODE,     "insertmode",       VAR_STRING, VV_RO),
@@ -586,6 +587,7 @@ void eval_init(void)
   v_event->dv_lock = VAR_FIXED;
   set_vim_var_dict(VV_EVENT, v_event);
   set_vim_var_list(VV_ERRORS, tv_list_alloc());
+  set_vim_var_nr(VV_STDERR,   CHAN_STDERR);
   set_vim_var_nr(VV_SEARCHFORWARD, 1L);
   set_vim_var_nr(VV_HLSEARCH, 1L);
   set_vim_var_nr(VV_COUNT1, 1);
@@ -7361,6 +7363,37 @@ static void f_chanclose(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   }
 }
 
+// "chansend(id, data)" function
+static void f_chansend(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+{
+  rettv->v_type = VAR_NUMBER;
+  rettv->vval.v_number = 0;
+
+  if (check_restricted() || check_secure()) {
+    return;
+  }
+
+  if (argvars[0].v_type != VAR_NUMBER || argvars[1].v_type == VAR_UNKNOWN) {
+    // First argument is the channel id and second is the data to write
+    EMSG(_(e_invarg));
+    return;
+  }
+
+  ptrdiff_t input_len = 0;
+  char *input = save_tv_as_string(&argvars[1], &input_len, false);
+  if (!input) {
+    // Either the error has been handled by save_tv_as_string(),
+    // or there is no input to send.
+    return;
+  }
+  uint64_t id = argvars[0].vval.v_number;
+  const char *error = NULL;
+  rettv->vval.v_number = channel_send(id, input, input_len, &error);
+  if (error) {
+    EMSG(error);
+  }
+}
+
 /*
  * "char2nr(string)" function
  */
@@ -11454,52 +11487,6 @@ static void f_jobpid(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   rettv->vval.v_number = proc->pid;
 }
 
-// "jobsend()" function
-static void f_jobsend(typval_T *argvars, typval_T *rettv, FunPtr fptr)
-{
-  rettv->v_type = VAR_NUMBER;
-  rettv->vval.v_number = 0;
-
-  if (check_restricted() || check_secure()) {
-    return;
-  }
-
-  if (argvars[0].v_type != VAR_NUMBER || argvars[1].v_type == VAR_UNKNOWN) {
-    // First argument is the job id and second is the string or list to write
-    // to the job's stdin
-    EMSG(_(e_invarg));
-    return;
-  }
-
-  Channel *data = find_channel(argvars[0].vval.v_number);
-  if (!data) {
-    EMSG(_(e_invchan));
-    return;
-  }
-
-  Stream *in = channel_instream(data);
-  if (in->closed) {
-    EMSG(_("Can't send data to the job: stdin is closed"));
-    return;
-  }
-
-  if (data->is_rpc) {
-    EMSG(_("Can't send raw data to rpc channel"));
-    return;
-  }
-
-  ptrdiff_t input_len = 0;
-  char *input = save_tv_as_string(&argvars[1], &input_len, false);
-  if (!input) {
-    // Either the error has been handled by save_tv_as_string(), or there is no
-    // input to send.
-    return;
-  }
-
-  WBuffer *buf = wstream_new_buffer(input, input_len, 1, xfree);
-  rettv->vval.v_number = wstream_write(in, buf);
-}
-
 // "jobresize(job, width, height)" function
 static void f_jobresize(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {

src/nvim/eval.h

@@ -56,6 +56,7 @@ typedef enum {
     VV_DYING,
     VV_EXCEPTION,
     VV_THROWPOINT,
+    VV_STDERR,
     VV_REG,
     VV_CMDBANG,
     VV_INSERTMODE,

src/nvim/eval.lua

@@ -56,6 +56,7 @@ return {
     ceil={args=1, func="float_op_wrapper", data="&ceil"},
     changenr={},
     chanclose={args={1, 2}},
+    chansend={args=2},
     char2nr={args={1, 2}},
     cindent={args=1},
     clearmatches={},
@@ -177,7 +178,7 @@ return {
     jobclose={args={1, 2}, func="f_chanclose"},
     jobpid={args=1},
     jobresize={args=3},
-    jobsend={args=2},
+    jobsend={args=2, func="f_chansend"},
     jobstart={args={1, 2}},
     jobstop={args=1},
     jobwait={args={1, 2}},

src/nvim/globals.h

@@ -1199,10 +1199,6 @@ EXTERN bool embedded_mode INIT(= false);
 // or read/write to stdio (unless embedding)
 EXTERN bool headless_mode INIT(= false);
 
-/// next free id for a job or rpc channel
-/// 1 is reserved for stdio channel
-EXTERN uint64_t next_chan_id INIT(= 2);
-
 /// Used to track the status of external functions.
 /// Currently only used for iconv().
 typedef enum {

src/nvim/main.c

@@ -297,7 +297,7 @@ int main(int argc, char **argv)
   assert(p_ch >= 0 && Rows >= p_ch && Rows - p_ch <= INT_MAX);
   cmdline_row = (int)(Rows - p_ch);
   msg_row = cmdline_row;
-  screenalloc(false);           /* allocate screen buffers */
+  screenalloc(false);  // allocate screen buffers
   set_init_2(headless_mode);
   TIME_MSG("inits 2");
 
@@ -310,8 +310,9 @@ int main(int argc, char **argv)
   /* Set the break level after the terminal is initialized. */
   debug_break_level = params.use_debug_break_level;
 
-  bool reading_input = !headless_mode && (params.input_isatty
-      || params.output_isatty || params.err_isatty);
+  bool reading_input = !headless_mode
+                       && (params.input_isatty || params.output_isatty
+                           || params.err_isatty);
 
   if (reading_input) {
     // One of the startup commands (arguments, sourced scripts or plugins) may