Create EventType for RStream reading

RStream will be the main way Neovim receives asynchronous messages, so it is
best to have a specialized EventType for it. A new flag parameter was added to
`rstream_new` which tells the RStream instance to defer event handling for later
with KE_EVENT instead of handling it directly from libuv callback.

src/os/event.c

@@ -8,6 +8,7 @@
 #include "os/event.h"
 #include "os/input.h"
 #include "os/signal.h"
+#include "os/rstream.h"
 #include "os/job.h"
 #include "vim.h"
 #include "memory.h"
@@ -112,6 +113,9 @@ void event_process()
       case kEventJobActivity:
         job_handle(event);
         break;
+      case kEventRStreamData:
+        rstream_read_event(event);
+        break;
       default:
         abort();
     }

src/os/event_defs.h

@@ -6,13 +6,18 @@
 
 typedef enum {
   kEventSignal,
-  kEventJobActivity
+  kEventJobActivity,
+  kEventRStreamData
 } EventType;
 
 typedef struct {
   EventType type;
   union {
     int signum;
+    struct {
+      RStream *ptr;
+      bool eof;
+    } rstream;
     struct {
       Job *ptr;
       RStream *target;

src/os/input.c

@@ -34,7 +34,7 @@ static int push_event_key(uint8_t *buf, int maxlen);
 
 void input_init()
 {
-  read_stream = rstream_new(read_cb, READ_BUFFER_SIZE, NULL);
+  read_stream = rstream_new(read_cb, READ_BUFFER_SIZE, NULL, false);
   rstream_set_file(read_stream, read_cmd_fd);
 }
 

src/os/job.c

@@ -159,8 +159,8 @@ int job_start(char **argv, void *data, job_read_cb cb)
   }
 
   // Start the readable streams
-  job->out = rstream_new(read_cb, JOB_BUFFER_SIZE, job);
-  job->err = rstream_new(read_cb, JOB_BUFFER_SIZE, job);
+  job->out = rstream_new(read_cb, JOB_BUFFER_SIZE, job, false);
+  job->err = rstream_new(read_cb, JOB_BUFFER_SIZE, job, false);
   rstream_set_stream(job->out, (uv_stream_t *)&job->proc_stdout);
   rstream_set_stream(job->err, (uv_stream_t *)&job->proc_stderr);
   rstream_start(job->out);

src/os/job.h

@@ -10,6 +10,7 @@
 #include <stdint.h>
 #include <stdbool.h>
 
+#include "os/event_defs.h"
 #include "os/event.h"
 
 /// Initializes job control resources

src/os/rstream.c

@@ -6,6 +6,8 @@
 
 #include "os/rstream_defs.h"
 #include "os/rstream.h"
+#include "os/event_defs.h"
+#include "os/event.h"
 #include "vim.h"
 #include "memory.h"
 
@@ -19,20 +21,25 @@ struct rstream {
   uv_file fd;
   rstream_cb cb;
   uint32_t buffer_size, rpos, wpos, fpos;
-  bool reading, free_handle;
+  bool reading, free_handle, async;
 };
 
 // Callbacks used by libuv
 static void alloc_cb(uv_handle_t *, size_t, uv_buf_t *);
 static void read_cb(uv_stream_t *, ssize_t, const uv_buf_t *);
 static void fread_idle_cb(uv_idle_t *);
+static void emit_read_event(RStream *rstream, bool eof);
 
-RStream * rstream_new(rstream_cb cb, uint32_t buffer_size, void *data)
+RStream * rstream_new(rstream_cb cb,
+                      uint32_t buffer_size,
+                      void *data,
+                      bool async)
 {
   RStream *rv = xmalloc(sizeof(RStream));
   rv->buffer = xmalloc(buffer_size);
   rv->buffer_size = buffer_size;
   rv->data = data;
+  rv->async = async;
   rv->cb = cb;
   rv->rpos = rv->wpos = rv->fpos = 0;
   rv->stream = NULL;
@@ -162,6 +169,13 @@ uint32_t rstream_available(RStream *rstream)
   return rstream->wpos - rstream->rpos;
 }
 
+void rstream_read_event(Event event)
+{
+  RStream *rstream = event.data.rstream.ptr;
+
+  rstream->cb(rstream, rstream->data, event.data.rstream.eof);
+}
+
 // Called by libuv to allocate memory for reading.
 static void alloc_cb(uv_handle_t *handle, size_t suggested, uv_buf_t *buf)
 {
@@ -191,7 +205,7 @@ static void read_cb(uv_stream_t *stream, ssize_t cnt, const uv_buf_t *buf)
       // Read error or EOF, either way stop the stream and invoke the callback
       // with eof == true
       uv_read_stop(stream);
-      rstream->cb(rstream, rstream->data, true);
+      emit_read_event(rstream, true);
     }
     return;
   }
@@ -205,11 +219,8 @@ static void read_cb(uv_stream_t *stream, ssize_t cnt, const uv_buf_t *buf)
     rstream_stop(rstream);
   }
 
-  // Invoke the callback passing in the number of bytes available and data
-  // associated with the stream
-  rstream->cb(rstream, rstream->data, false);
   rstream->reading = false;
-
+  emit_read_event(rstream, false);
 }
 
 // Called by the by the 'idle' handle to emulate a reading event
@@ -235,7 +246,7 @@ static void fread_idle_cb(uv_idle_t *handle)
 
   if (req.result <= 0) {
     uv_idle_stop(rstream->fread_idle);
-    rstream->cb(rstream, rstream->data, true);
+    emit_read_event(rstream, true);
     return;
   }
 
@@ -247,5 +258,21 @@ static void fread_idle_cb(uv_idle_t *handle)
     rstream_stop(rstream);
   }
 
-  rstream->cb(rstream, rstream->data, false);
+  emit_read_event(rstream, false);
+}
+
+static void emit_read_event(RStream *rstream, bool eof)
+{
+  if (rstream->async) {
+    Event event;
+
+    event.type = kEventRStreamData;
+    event.data.rstream.ptr = rstream;
+    event.data.rstream.eof = eof;
+    event_push(event);
+  } else {
+    // Invoke the callback passing in the number of bytes available and data
+    // associated with the stream
+    rstream->cb(rstream, rstream->data, eof);
+  }
 }

src/os/rstream.h

@@ -5,6 +5,7 @@
 #include <stdint.h>
 #include <uv.h>
 
+#include "os/event_defs.h"
 #include "os/rstream_defs.h"
 
 /// Creates a new RStream instance. A RStream encapsulates all the boilerplate
@@ -14,8 +15,15 @@
 ///        for reading with `rstream_read`
 /// @param buffer_size Size in bytes of the internal buffer.
 /// @param data Some state to associate with the `RStream` instance
+/// @param async Flag that specifies if the callback should only be called
+///        outside libuv event loop(When processing async events with
+///        KE_EVENT). Only the RStream instance reading user input should set
+///        this to false
 /// @return The newly-allocated `RStream` instance
-RStream * rstream_new(rstream_cb cb, uint32_t buffer_size, void *data);
+RStream * rstream_new(rstream_cb cb,
+                      uint32_t buffer_size,
+                      void *data,
+                      bool async);
 
 /// Frees all memory allocated for a RStream instance
 ///
@@ -71,5 +79,10 @@ uint32_t rstream_read(RStream *rstream, char *buffer, uint32_t count);
 /// @return The number of bytes available
 uint32_t rstream_available(RStream *rstream);
 
+/// Runs the read callback associated with the rstream
+///
+/// @param event Object containing data necessary to invoke the callback
+void rstream_read_event(Event event);
+
 #endif  // NEOVIM_OS_RSTREAM_H