Add argument to not send a buffers content when updates are enabled

Add a test.

src/nvim/api/buffer.c

@@ -87,6 +87,7 @@ String buffer_get_line(Buffer buffer, Integer index, Error *err)
 Boolean nvim_buf_live_updates(uint64_t channel_id,
                               Buffer buffer,
                               Boolean enabled,
+                              Boolean send_buffer,
                               Error *err)
   FUNC_API_SINCE(3) FUNC_API_REMOTE_ONLY
 {
@@ -97,7 +98,7 @@ Boolean nvim_buf_live_updates(uint64_t channel_id,
   }
 
   if (enabled) {
-    return liveupdate_register(buf, channel_id);
+    return liveupdate_register(buf, channel_id, send_buffer);
   }
 
   liveupdate_unregister(buf, channel_id);

src/nvim/liveupdate.c

@@ -6,7 +6,7 @@
 // Register a channel. Return True if the channel was added, or already added.
 // Return False if the channel couldn't be added because the buffer is
 // unloaded.
-bool liveupdate_register(buf_T *buf, uint64_t channel_id)
+bool liveupdate_register(buf_T *buf, uint64_t channel_id, bool send_buffer)
 {
   // must fail if the buffer isn't loaded
   if (buf->b_ml.ml_mfp == NULL) {
@@ -27,21 +27,23 @@ bool liveupdate_register(buf_T *buf, uint64_t channel_id)
   // append the channelid to the list
   kv_push(buf->liveupdate_channels, channel_id);
 
-  // send through the full channel contents now
   Array linedata = ARRAY_DICT_INIT;
-  size_t line_count = buf->b_ml.ml_line_count;
+  if (send_buffer) {
-  linedata.size = line_count;
+    // collect buffer contents
-  linedata.items = xcalloc(sizeof(Object), line_count);
+    size_t line_count = buf->b_ml.ml_line_count;
-  for (size_t i = 0; i < line_count; i++) {
+    linedata.size = line_count;
-    linenr_T lnum = 1 + (linenr_T)i;
+    linedata.items = xcalloc(sizeof(Object), line_count);
+    for (size_t i = 0; i < line_count; i++) {
+      linenr_T lnum = 1 + (linenr_T)i;
 
-    const char *bufstr = (char *)ml_get_buf(buf, lnum, false);
+      const char *bufstr = (char *)ml_get_buf(buf, lnum, false);
-    Object str = STRING_OBJ(cstr_to_string(bufstr));
+      Object str = STRING_OBJ(cstr_to_string(bufstr));
 
-    // Vim represents NULs as NLs, but this may confuse clients.
+      // Vim represents NULs as NLs, but this may confuse clients.
-    strchrsub(str.data.string.data, '\n', '\0');
+      strchrsub(str.data.string.data, '\n', '\0');
 
-    linedata.items[i] = str;
+      linedata.items[i] = str;
+    }
   }
 
   Array args = ARRAY_DICT_INIT;

src/nvim/liveupdate.h

@@ -3,7 +3,7 @@
 
 #include "nvim/buffer_defs.h"
 
-bool liveupdate_register(buf_T *buf, uint64_t channel_id);
+bool liveupdate_register(buf_T *buf, uint64_t channel_id, bool send_buffer);
 void liveupdate_unregister(buf_T *buf, uint64_t channel_id);
 void liveupdate_unregister_all(buf_T *buf);
 void liveupdate_send_changes(buf_T *buf, linenr_T firstline, int64_t num_added,

test/functional/api/liveupdate_spec.lua

@@ -39,7 +39,7 @@ function open(activate, lines)
   -- turn on live updates, ensure that the LiveUpdateStart messages
   -- arrive as expectected
   if activate then
-    ok(buffer('live_updates', b, true))
+    ok(buffer('live_updates', b, true, true))
     expectn('LiveUpdateStart', {b, tick, lines, false})
   end
 
@@ -47,12 +47,12 @@ function open(activate, lines)
 end
 
 function reopen(buf, expectedlines)
-  ok(buffer('live_updates', buf, false))
+  ok(buffer('live_updates', buf, false, true))
   expectn('LiveUpdateEnd', {buf})
   -- for some reason the :edit! increments tick by 2
   command('edit!')
   local tick = eval('b:changedtick')
-  ok(buffer('live_updates', buf, true))
+  ok(buffer('live_updates', buf, true, true))
   expectn('LiveUpdateStart', {buf, tick, origlines, false})
   command('normal! gg')
   return tick
@@ -161,20 +161,20 @@ describe('liveupdate', function()
     command('enew')
     local tick = eval('b:changedtick')
     b2 = nvim('get_current_buf')
-    ok(buffer('live_updates', b2, true))
+    ok(buffer('live_updates', b2, true, true))
     expectn('LiveUpdateStart', {b2, tick, {""}, false})
     eval('append(0, ["new line 1"])')
     tick = tick + 1
     expectn('LiveUpdate', {b2, tick, 0, 0, {'new line 1'}})
 
     -- turn off live updates manually
-    buffer('live_updates', b2, false)
+    buffer('live_updates', b2, false, true)
     expectn('LiveUpdateEnd', {b2})
 
     -- add multiple lines to a blank file
     command('enew!')
     b3 = nvim('get_current_buf')
-    ok(buffer('live_updates', b3, true))
+    ok(buffer('live_updates', b3, true, true))
     tick = eval('b:changedtick')
     expectn('LiveUpdateStart', {b3, tick, {""}, false})
     eval('append(0, ["new line 1", "new line 2", "new line 3"])')
@@ -267,7 +267,7 @@ describe('liveupdate', function()
     tick = 2
     expectn('LiveUpdateEnd', {b})
     bnew = nvim('get_current_buf')
-    ok(buffer('live_updates', bnew, true))
+    ok(buffer('live_updates', bnew, true, true))
     expectn('LiveUpdateStart', {bnew, tick, {''}, false})
     sendkeys('i')
     sendkeys('h')
@@ -440,21 +440,21 @@ describe('liveupdate', function()
     local b, tick = editoriginal(false)
 
     -- turn on live updates many times
-    ok(buffer('live_updates', b, true))
+    ok(buffer('live_updates', b, true, true))
-    ok(buffer('live_updates', b, true))
+    ok(buffer('live_updates', b, true, true))
-    ok(buffer('live_updates', b, true))
+    ok(buffer('live_updates', b, true, true))
-    ok(buffer('live_updates', b, true))
+    ok(buffer('live_updates', b, true, true))
-    ok(buffer('live_updates', b, true))
+    ok(buffer('live_updates', b, true, true))
     expectn('LiveUpdateStart', {b, tick, origlines, false})
     eval('rpcnotify('..channel..', "Hello There")')
     expectn('Hello There', {})
 
     -- turn live updates off many times
-    ok(buffer('live_updates', b, false))
+    ok(buffer('live_updates', b, false, true))
-    ok(buffer('live_updates', b, false))
+    ok(buffer('live_updates', b, false, true))
-    ok(buffer('live_updates', b, false))
+    ok(buffer('live_updates', b, false, true))
-    ok(buffer('live_updates', b, false))
+    ok(buffer('live_updates', b, false, true))
-    ok(buffer('live_updates', b, false))
+    ok(buffer('live_updates', b, false, true))
     expectn('LiveUpdateEnd', {b})
     eval('rpcnotify('..channel..', "Hello Again")')
     expectn('Hello Again', {})
@@ -493,9 +493,9 @@ describe('liveupdate', function()
     local b, tick = open(false, lines)
 
     -- turn on live updates for sessions 1, 2 and 3
-    ok(request(1, 'nvim_buf_live_updates', b, true))
+    ok(request(1, 'nvim_buf_live_updates', b, true, true))
-    ok(request(2, 'nvim_buf_live_updates', b, true))
+    ok(request(2, 'nvim_buf_live_updates', b, true, true))
-    ok(request(3, 'nvim_buf_live_updates', b, true))
+    ok(request(3, 'nvim_buf_live_updates', b, true, true))
     wantn(1, 'LiveUpdateStart', {b, tick, lines, false})
     wantn(2, 'LiveUpdateStart', {b, tick, lines, false})
     wantn(3, 'LiveUpdateStart', {b, tick, lines, false})
@@ -508,7 +508,7 @@ describe('liveupdate', function()
     wantn(3, 'LiveUpdate', {b, tick, 0, 1, {'AA'}})
 
     -- stop watching on channel 1
-    ok(request(1, 'nvim_buf_live_updates', b, false))
+    ok(request(1, 'nvim_buf_live_updates', b, false, true))
     wantn(1, 'LiveUpdateEnd', {b})
 
     -- undo the change to buffer 1
@@ -731,4 +731,12 @@ describe('liveupdate', function()
       expectn('LiveUpdateEnd', {b})
     end
   end)
+
+  it('doesn\'t send the buffer\'s content when not requested', function()
+    helpers.clear()
+    local b, tick = editoriginal(false)
+    ok(buffer('live_updates', b, true, false))
+    expectn('LiveUpdateStart', {b, tick, {}, false})
+  end)
+
 end)