1 files changed, 116 insertions, 99 deletions

diff --git a/src/nvim/os/input.c b/src/nvim/os/input.c
index 60b5b48745..7c5293a8b8 100644
--- a/src/nvim/os/input.c
+++ b/src/nvim/os/input.c
@@ -27,22 +27,17 @@
 #include "nvim/os/os_defs.h"
 #include "nvim/os/time.h"
 #include "nvim/profile.h"
-#include "nvim/rbuffer.h"
-#include "nvim/rbuffer_defs.h"
 #include "nvim/state.h"
 #include "nvim/state_defs.h"
 
 #define READ_BUFFER_SIZE 0xfff
-#define INPUT_BUFFER_SIZE (READ_BUFFER_SIZE * 4)
+#define INPUT_BUFFER_SIZE ((READ_BUFFER_SIZE * 4) + MAX_KEY_CODE_LEN)
 
-typedef enum {
-  kInputNone,
-  kInputAvail,
-  kInputEof,
-} InbufPollResult;
+static RStream read_stream = { .s.closed = true };  // Input before UI starts.
+static char input_buffer[INPUT_BUFFER_SIZE];
+static char *input_read_pos = input_buffer;
+static char *input_write_pos = input_buffer;
 
-static Stream read_stream = { .closed = true };  // Input before UI starts.
-static RBuffer *input_buffer = NULL;
 static bool input_eof = false;
 static bool blocking = false;
 static int cursorhold_time = 0;  ///< time waiting for CursorHold event
@@ -52,39 +47,27 @@ static int cursorhold_tb_change_cnt = 0;  ///< tb_change_cnt when waiting starte
 # include "os/input.c.generated.h"
 #endif
 
-void input_init(void)
-{
-  input_buffer = rbuffer_new(INPUT_BUFFER_SIZE + MAX_KEY_CODE_LEN);
-}
-
 void input_start(void)
 {
-  if (!read_stream.closed) {
+  if (!read_stream.s.closed) {
     return;
   }
 
   used_stdin = true;
-  rstream_init_fd(&main_loop, &read_stream, STDIN_FILENO, READ_BUFFER_SIZE);
+  rstream_init_fd(&main_loop, &read_stream, STDIN_FILENO);
   rstream_start(&read_stream, input_read_cb, NULL);
 }
 
 void input_stop(void)
 {
-  if (read_stream.closed) {
+  if (read_stream.s.closed) {
     return;
   }
 
   rstream_stop(&read_stream);
-  stream_close(&read_stream, NULL, NULL);
+  rstream_may_close(&read_stream);
 }
 
-#ifdef EXITFREE
-void input_free_all_mem(void)
-{
-  rbuffer_free(input_buffer);
-}
-#endif
-
 static void cursorhold_event(void **argv)
 {
   event_T event = State & MODE_INSERT ? EVENT_CURSORHOLDI : EVENT_CURSORHOLD;
@@ -95,54 +78,76 @@ static void cursorhold_event(void **argv)
 static void create_cursorhold_event(bool events_enabled)
 {
   // If events are enabled and the queue has any items, this function should not
-  // have been called (inbuf_poll would return kInputAvail).
+  // have been called (`inbuf_poll` would return `kTrue`).
   // TODO(tarruda): Cursorhold should be implemented as a timer set during the
   // `state_check` callback for the states where it can be triggered.
   assert(!events_enabled || multiqueue_empty(main_loop.events));
   multiqueue_put(main_loop.events, cursorhold_event, NULL);
 }
 
-static void restart_cursorhold_wait(int tb_change_cnt)
+static void reset_cursorhold_wait(int tb_change_cnt)
 {
   cursorhold_time = 0;
   cursorhold_tb_change_cnt = tb_change_cnt;
 }
 
-/// Low level input function
+/// Reads OS input into `buf`, and consumes pending events while waiting (if `ms != 0`).
 ///
-/// Wait until either the input buffer is non-empty or, if `events` is not NULL
-/// until `events` is non-empty.
-int os_inchar(uint8_t *buf, int maxlen, int ms, int tb_change_cnt, MultiQueue *events)
+/// - Consumes available input received from the OS.
+/// - Consumes pending events.
+/// - Manages CursorHold events.
+/// - Handles EOF conditions.
+///
+/// Originally based on the Vim `mch_inchar` function.
+///
+/// @param buf Buffer to store consumed input.
+/// @param maxlen Maximum bytes to read into `buf`, or 0 to skip reading.
+/// @param ms Timeout in milliseconds. -1 for indefinite wait, 0 for no wait.
+/// @param tb_change_cnt Used to detect when typeahead changes.
+/// @param events (optional) Events to process.
+/// @return Bytes read into buf, or 0 if no input was read
+int input_get(uint8_t *buf, int maxlen, int ms, int tb_change_cnt, MultiQueue *events)
 {
   // This check is needed so that feeding typeahead from RPC can prevent CursorHold.
   if (tb_change_cnt != cursorhold_tb_change_cnt) {
-    restart_cursorhold_wait(tb_change_cnt);
+    reset_cursorhold_wait(tb_change_cnt);
   }
 
-  if (maxlen && rbuffer_size(input_buffer)) {
-    restart_cursorhold_wait(tb_change_cnt);
-    return (int)rbuffer_read(input_buffer, (char *)buf, (size_t)maxlen);
-  }
+#define TRY_READ() \
+  do { \
+    if (maxlen && input_available()) { \
+      reset_cursorhold_wait(tb_change_cnt); \
+      assert(maxlen >= 0); \
+      size_t to_read = MIN((size_t)maxlen, input_available()); \
+      memcpy(buf, input_read_pos, to_read); \
+      input_read_pos += to_read; \
+      /* This is safe because INPUT_BUFFER_SIZE fits in an int. */ \
+      assert(to_read <= INT_MAX); \
+      return (int)to_read; \
+    } \
+  } while (0)
+
+  TRY_READ();
 
   // No risk of a UI flood, so disable CTRL-C "interrupt" behavior if it's mapped.
   if ((mapped_ctrl_c | curbuf->b_mapped_ctrl_c) & get_real_state()) {
     ctrl_c_interrupts = false;
   }
 
-  InbufPollResult result;
+  TriState result;  ///< inbuf_poll result.
   if (ms >= 0) {
-    if ((result = inbuf_poll(ms, events)) == kInputNone) {
+    if ((result = inbuf_poll(ms, events)) == kFalse) {
       return 0;
     }
   } else {
     uint64_t wait_start = os_hrtime();
     cursorhold_time = MIN(cursorhold_time, (int)p_ut);
-    if ((result = inbuf_poll((int)p_ut - cursorhold_time, events)) == kInputNone) {
-      if (read_stream.closed && silent_mode) {
+    if ((result = inbuf_poll((int)p_ut - cursorhold_time, events)) == kFalse) {
+      if (read_stream.s.closed && silent_mode) {
         // Drained eventloop & initial input; exit silent/batch-mode (-es/-Es).
         read_error_exit();
       }
-      restart_cursorhold_wait(tb_change_cnt);
+      reset_cursorhold_wait(tb_change_cnt);
       if (trigger_cursorhold() && !typebuf_changed(tb_change_cnt)) {
         create_cursorhold_event(events == main_loop.events);
       } else {
@@ -161,29 +166,26 @@ int os_inchar(uint8_t *buf, int maxlen, int ms, int tb_change_cnt, MultiQueue *e
     return 0;
   }
 
-  if (maxlen && rbuffer_size(input_buffer)) {
-    restart_cursorhold_wait(tb_change_cnt);
-    // Safe to convert rbuffer_read to int, it will never overflow since we use
-    // relatively small buffers.
-    return (int)rbuffer_read(input_buffer, (char *)buf, (size_t)maxlen);
-  }
+  TRY_READ();
 
   // If there are events, return the keys directly
   if (maxlen && pending_events(events)) {
     return push_event_key(buf, maxlen);
   }
 
-  if (result == kInputEof) {
+  if (result == kNone) {
     read_error_exit();
   }
 
   return 0;
+
+#undef TRY_READ
 }
 
 // Check if a character is available for reading
 bool os_char_avail(void)
 {
-  return inbuf_poll(0, NULL) == kInputAvail;
+  return inbuf_poll(0, NULL) == kTrue;
 }
 
 /// Poll for fast events. `got_int` will be set to `true` if CTRL-C was typed.
@@ -247,11 +249,28 @@ bool os_isatty(int fd)
   return uv_guess_handle(fd) == UV_TTY;
 }
 
-void input_enqueue_raw(String keys)
+size_t input_available(void)
 {
-  if (keys.size > 0) {
-    rbuffer_write(input_buffer, keys.data, keys.size);
+  return (size_t)(input_write_pos - input_read_pos);
+}
+
+static size_t input_space(void)
+{
+  return (size_t)(input_buffer + INPUT_BUFFER_SIZE - input_write_pos);
+}
+
+void input_enqueue_raw(const char *data, size_t size)
+{
+  if (input_read_pos > input_buffer) {
+    size_t available = input_available();
+    memmove(input_buffer, input_read_pos, available);
+    input_read_pos = input_buffer;
+    input_write_pos = input_buffer + available;
   }
+
+  size_t to_write = MIN(size, input_space());
+  memcpy(input_write_pos, data, to_write);
+  input_write_pos += to_write;
 }
 
 size_t input_enqueue(String keys)
@@ -259,7 +278,7 @@ size_t input_enqueue(String keys)
   const char *ptr = keys.data;
   const char *end = ptr + keys.size;
 
-  while (rbuffer_space(input_buffer) >= 19 && ptr < end) {
+  while (input_space() >= 19 && ptr < end) {
     // A "<x>" form occupies at least 1 characters, and produces up
     // to 19 characters (1 + 5 * 3 for the char and 3 for a modifier).
     // In the case of K_SPECIAL (0x80), 3 bytes are escaped and needed,
@@ -272,7 +291,7 @@ size_t input_enqueue(String keys)
 
     if (new_size) {
       new_size = handle_mouse_event(&ptr, buf, new_size);
-      rbuffer_write(input_buffer, (char *)buf, new_size);
+      input_enqueue_raw((char *)buf, new_size);
       continue;
     }
 
@@ -293,11 +312,11 @@ size_t input_enqueue(String keys)
 
     // copy the character, escaping K_SPECIAL
     if ((uint8_t)(*ptr) == K_SPECIAL) {
-      rbuffer_write(input_buffer, (char *)&(uint8_t){ K_SPECIAL }, 1);
-      rbuffer_write(input_buffer, (char *)&(uint8_t){ KS_SPECIAL }, 1);
-      rbuffer_write(input_buffer, (char *)&(uint8_t){ KE_FILLER }, 1);
+      input_enqueue_raw((char *)&(uint8_t){ K_SPECIAL }, 1);
+      input_enqueue_raw((char *)&(uint8_t){ KS_SPECIAL }, 1);
+      input_enqueue_raw((char *)&(uint8_t){ KE_FILLER }, 1);
     } else {
-      rbuffer_write(input_buffer, ptr, 1);
+      input_enqueue_raw(ptr, 1);
     }
     ptr++;
   }
@@ -422,7 +441,7 @@ static unsigned handle_mouse_event(const char **ptr, uint8_t *buf, unsigned bufs
   return bufsize;
 }
 
-size_t input_enqueue_mouse(int code, uint8_t modifier, int grid, int row, int col)
+void input_enqueue_mouse(int code, uint8_t modifier, int grid, int row, int col)
 {
   modifier |= check_multiclick(code, grid, row, col);
   uint8_t buf[7];
@@ -442,8 +461,7 @@ size_t input_enqueue_mouse(int code, uint8_t modifier, int grid, int row, int co
   mouse_col = col;
 
   size_t written = 3 + (size_t)(p - buf);
-  rbuffer_write(input_buffer, (char *)buf, written);
-  return written;
+  input_enqueue_raw((char *)buf, written);
 }
 
 /// @return true if the main loop is blocked and waiting for input.
@@ -452,15 +470,22 @@ bool input_blocking(void)
   return blocking;
 }
 
-// This is a replacement for the old `WaitForChar` function in os_unix.c
-static InbufPollResult inbuf_poll(int ms, MultiQueue *events)
+/// Checks for (but does not read) available input, and consumes `main_loop.events` while waiting.
+///
+/// @param ms Timeout in milliseconds. -1 for indefinite wait, 0 for no wait.
+/// @param events (optional) Queue to check for pending events.
+/// @return TriState:
+///   - kTrue: Input/events available
+///   - kFalse: No input/events
+///   - kNone: EOF reached on the input stream
+static TriState inbuf_poll(int ms, MultiQueue *events)
 {
   if (os_input_ready(events)) {
-    return kInputAvail;
+    return kTrue;
   }
 
   if (do_profiling == PROF_YES && ms) {
-    prof_inchar_enter();
+    prof_input_start();
   }
 
   if ((ms == -1 || ms > 0) && events != main_loop.events && !input_eof) {
@@ -468,38 +493,29 @@ static InbufPollResult inbuf_poll(int ms, MultiQueue *events)
     blocking = true;
     multiqueue_process_events(ch_before_blocking_events);
   }
-  DLOG("blocking... events_enabled=%d events_pending=%d", events != NULL,
-       events && !multiqueue_empty(events));
-  LOOP_PROCESS_EVENTS_UNTIL(&main_loop, NULL, ms,
-                            os_input_ready(events) || input_eof);
+  DLOG("blocking... events=%s", !!events ? "true" : "false");
+  LOOP_PROCESS_EVENTS_UNTIL(&main_loop, NULL, ms, os_input_ready(events) || input_eof);
   blocking = false;
 
   if (do_profiling == PROF_YES && ms) {
-    prof_inchar_exit();
+    prof_input_end();
   }
 
   if (os_input_ready(events)) {
-    return kInputAvail;
+    return kTrue;
   }
-  return input_eof ? kInputEof : kInputNone;
-}
-
-bool input_available(void)
-{
-  return rbuffer_size(input_buffer) != 0;
+  return input_eof ? kNone : kFalse;
 }
 
-static void input_read_cb(Stream *stream, RBuffer *buf, size_t c, void *data, bool at_eof)
+static size_t input_read_cb(RStream *stream, const char *buf, size_t c, void *data, bool at_eof)
 {
   if (at_eof) {
     input_eof = true;
   }
 
-  assert(rbuffer_space(input_buffer) >= rbuffer_size(buf));
-  RBUFFER_UNTIL_EMPTY(buf, ptr, len) {
-    (void)rbuffer_write(input_buffer, ptr, len);
-    rbuffer_consumed(buf, len);
-  }
+  assert(input_space() >= c);
+  input_enqueue_raw(buf, c);
+  return c;
 }
 
 static void process_ctrl_c(void)
@@ -508,28 +524,29 @@ static void process_ctrl_c(void)
     return;
   }
 
-  size_t consume_count = 0;
-  RBUFFER_EACH_REVERSE(input_buffer, c, i) {
-    if ((uint8_t)c == Ctrl_C
-        || ((uint8_t)c == 'C' && i >= 3
-            && (uint8_t)(*rbuffer_get(input_buffer, i - 3)) == K_SPECIAL
-            && (uint8_t)(*rbuffer_get(input_buffer, i - 2)) == KS_MODIFIER
-            && (uint8_t)(*rbuffer_get(input_buffer, i - 1)) == MOD_MASK_CTRL)) {
-      *rbuffer_get(input_buffer, i) = Ctrl_C;
+  size_t available = input_available();
+  ssize_t i;
+  for (i = (ssize_t)available - 1; i >= 0; i--) {  // Reverse-search input for Ctrl_C.
+    uint8_t c = (uint8_t)input_read_pos[i];
+    if (c == Ctrl_C
+        || (c == 'C' && i >= 3
+            && (uint8_t)input_read_pos[i - 3] == K_SPECIAL
+            && (uint8_t)input_read_pos[i - 2] == KS_MODIFIER
+            && (uint8_t)input_read_pos[i - 1] == MOD_MASK_CTRL)) {
+      input_read_pos[i] = Ctrl_C;
       got_int = true;
-      consume_count = i;
       break;
     }
   }
 
-  if (got_int && consume_count) {
+  if (got_int && i > 0) {
     // Remove all unprocessed input (typeahead) before the CTRL-C.
-    rbuffer_consumed(input_buffer, consume_count);
+    input_read_pos += i;
   }
 }
 
-// Helper function used to push bytes from the 'event' key sequence partially
-// between calls to os_inchar when maxlen < 3
+/// Pushes bytes from the "event" key sequence (KE_EVENT) partially between calls to input_get when
+/// `maxlen < 3`.
 static int push_event_key(uint8_t *buf, int maxlen)
 {
   static const uint8_t key[3] = { K_SPECIAL, KS_EXTRA, KE_EVENT };
@@ -548,7 +565,7 @@ static int push_event_key(uint8_t *buf, int maxlen)
 bool os_input_ready(MultiQueue *events)
 {
   return (typebuf_was_filled             // API call filled typeahead
-          || rbuffer_size(input_buffer)  // Input buffer filled
+          || input_available()           // Input buffer filled
           || pending_events(events));    // Events must be processed
 }
 
@@ -559,7 +576,7 @@ static void read_error_exit(void)
   if (silent_mode) {  // Normal way to exit for "nvim -es".
     getout(0);
   }
-  preserve_exit(_("Vim: Error reading input, exiting...\n"));
+  preserve_exit(_("Nvim: Error reading input, exiting...\n"));
 }
 
 static bool pending_events(MultiQueue *events)