clipboard: handle clipboard reading directly in get_yank_register

This makes :<c-r>* work as expected and
avoids clobbering zero register ("0) when pasting unnamed clipboard

Helped-By: Scott Prager <splinterofchaos@gmail.com>
Helped-By: Michael Reed <m.reed@mykolab.com>

src/nvim/ops.c

@@ -53,7 +53,7 @@
 
 /*
  * Registers:
- *      0 = unnamed register, for normal yanks and puts
+ *      0 = register for latest (unnamed) yank
  *   1..9 = registers '1' to '9', for deletes
  * 10..35 = registers 'a' to 'z'
  *     36 = delete register '-'
@@ -68,7 +68,6 @@
 #define NUM_REGISTERS 39
 
 #define CB_UNNAMEDMASK (CB_UNNAMED | CB_UNNAMEDPLUS)
-#define CB_LATEST (-1)
 /*
  * Each yank register is an array of pointers to lines.
  */
@@ -748,21 +747,37 @@ valid_yank_reg (
   return FALSE;
 }
 
-/*
+typedef enum {
- * Set y_current and y_append, according to the value of "regname".
+  YREG_PASTE,
- * Cannot handle the '_' register.
+  YREG_YANK,
- * Must only be called with a valid register name!
+  YREG_PUT,
- *
+} yreg_mode_t;
- * If regname is 0 and writing, use register 0
+
- * If regname is 0 and reading, use previous register
+/// Set y_current and y_append, according to the value of `regname`.
- */
+/// Cannot handle the '_' (black hole) register.
-void get_yank_register(int regname, int writing)
+/// Must only be called with a valid register name!
+///
+/// @param regname The name of the register used or 0 for the unnamed register
+/// @param mode One of the following three flags:
+///
+/// `YREG_PASTE`:
+/// Prepare for pasting the register `regname`. With no regname specified,
+/// read from last written register, or from unnamed clipboard (depending on the
+/// `clipboard=unnamed` option). Queries the clipboard provider if necessary.
+///
+/// `YREG_YANK`:
+/// Preparare for yanking into `regname`. With no regname specified,
+/// yank into `"0` register. Update `y_previous` for next unnamed paste.
+///
+/// `YREG_PUT`:
+/// Obtain the location that would be read when pasting `regname`.
+void get_yank_register(int regname, int mode)
 {
   int i;
 
   y_append = FALSE;
   int unnamedclip = cb_flags & CB_UNNAMEDMASK;
-  if ((regname == 0 || regname == '"') && !unnamedclip && !writing && y_previous != NULL) {
+  if ((regname == 0 || regname == '"') && !unnamedclip && mode != YREG_YANK && y_previous != NULL) {
     y_current = y_previous;
     return;
   }
@@ -783,8 +798,12 @@ void get_yank_register(int regname, int writing)
   else                  /* not 0-9, a-z, A-Z or '-': use register 0 */
     i = 0;
   y_current = &(y_regs[i]);
-  if (writing)          /* remember the register we write into for do_put() */
+  if (mode == YREG_YANK) {
+    // remember the written register for unnamed paste
     y_previous = y_current;
+  } else if (mode == YREG_PASTE) {
+    get_clipboard(regname, &y_current, false);
+  }
 }
 
 
@@ -798,8 +817,7 @@ get_register (
     int copy               /* make a copy, if FALSE make register empty. */
 ) FUNC_ATTR_NONNULL_RET
 {
-  get_yank_register(name, 0);
+  get_yank_register(name, YREG_PASTE);
-  get_clipboard(name, false);
 
   struct yankreg *reg = xmalloc(sizeof(struct yankreg));
   *reg = *y_current;
@@ -823,7 +841,7 @@ get_register (
  */
 void put_register(int name, void *reg)
 {
-  get_yank_register(name, 0);
+  get_yank_register(name, YREG_PUT);
   free_yank_all();
   *y_current = *(struct yankreg *)reg;
   free(reg);
@@ -839,7 +857,7 @@ int yank_register_mline(int regname)
     return FALSE;
   if (regname == '_')           /* black hole is always empty */
     return FALSE;
-  get_yank_register(regname, FALSE);
+  get_yank_register(regname, YREG_PASTE);
   return y_current->y_type == MLINE;
 }
 
@@ -913,7 +931,7 @@ static int stuff_yank(int regname, char_u *p)
     free(p);
     return OK;
   }
-  get_yank_register(regname, TRUE);
+  get_yank_register(regname, YREG_YANK);
   if (y_append && y_current->y_array != NULL) {
     char_u **pp = &(y_current->y_array[y_current->y_size - 1]);
     char_u *lp = xmalloc(STRLEN(*pp) + STRLEN(p) + 1);
@@ -967,8 +985,6 @@ do_execreg (
   }
   execreg_lastc = regname;
 
-  get_clipboard(regname, false);
-
   if (regname == '_')                   /* black hole: don't stuff anything */
     return OK;
 
@@ -1007,7 +1023,7 @@ do_execreg (
     retval = put_in_typebuf(p, FALSE, colon, silent);
     free(p);
   } else {
-    get_yank_register(regname, FALSE);
+    get_yank_register(regname, YREG_PASTE);
     if (y_current->y_array == NULL)
       return FAIL;
 
@@ -1132,8 +1148,6 @@ insert_reg (
   if (regname != NUL && !valid_yank_reg(regname, FALSE))
     return FAIL;
 
-  get_clipboard(regname, false);
-
   if (regname == '.')                   /* insert last inserted text */
     retval = stuff_inserted(NUL, 1L, TRUE);
   else if (get_spec_reg(regname, &arg, &allocated, TRUE)) {
@@ -1143,7 +1157,7 @@ insert_reg (
     if (allocated)
       free(arg);
   } else {                            /* name or number register */
-    get_yank_register(regname, FALSE);
+    get_yank_register(regname, YREG_PASTE);
     if (y_current->y_array == NULL)
       retval = FAIL;
     else {
@@ -1290,7 +1304,7 @@ cmdline_paste_reg (
 {
   long i;
 
-  get_yank_register(regname, FALSE);
+  get_yank_register(regname, YREG_PASTE);
   if (y_current->y_array == NULL)
     return FAIL;
 
@@ -1397,7 +1411,7 @@ int op_delete(oparg_T *oap)
         beep_flush();
         return OK;
       }
-      get_yank_register(oap->regname, TRUE);       /* yank into specif'd reg. */
+      get_yank_register(oap->regname, YREG_YANK); /* yank into specif'd reg. */
       if (op_yank(oap, TRUE, FALSE) == OK)         /* yank without message */
         did_yank = TRUE;
     }
@@ -1423,14 +1437,14 @@ int op_delete(oparg_T *oap)
     if (oap->regname == 0 && oap->motion_type != MLINE
         && oap->line_count == 1) {
       oap->regname = '-';
-      get_yank_register(oap->regname, TRUE);
+      get_yank_register(oap->regname, YREG_YANK);
       if (op_yank(oap, TRUE, FALSE) == OK)
         did_yank = TRUE;
       oap->regname = 0;
     }
 
     if(oap->regname == 0 && did_yank) {
-      set_clipboard(CB_LATEST);
+      set_clipboard(0);
     }
     /*
      * If there's too much stuff to fit in the yank register, then get a
@@ -2372,7 +2386,7 @@ int op_yank(oparg_T *oap, int deleting, int mess)
     return OK;
 
   if (!deleting)                    /* op_delete() already set y_current */
-    get_yank_register(oap->regname, TRUE);
+    get_yank_register(oap->regname, YREG_YANK);
 
   curr = y_current;
   /* append to existing contents */
@@ -2620,8 +2634,6 @@ do_put (
   int allocated = FALSE;
   long cnt;
 
-  get_clipboard(regname, false);
-
   if (flags & PUT_FIXINDENT)
     orig_indent = get_indent();
 
@@ -2694,7 +2706,7 @@ do_put (
       y_array = &insert_string;
     }
   } else {
-    get_yank_register(regname, FALSE);
+    get_yank_register(regname, YREG_PASTE);
 
     y_type = y_current->y_type;
     y_width = y_current->y_width;
@@ -3233,7 +3245,6 @@ void ex_display(exarg_T *eap)
       continue;             /* did not ask for this register */
     }
 
-    get_clipboard(name, true);
 
     if (i == -1) {
       if (y_previous != NULL)
@@ -3243,6 +3254,8 @@ void ex_display(exarg_T *eap)
     } else
       yb = &(y_regs[i]);
 
+    get_clipboard(name, &yb, true);
+
     if (name == vim_tolower(redir_reg)
         || (redir_reg == '"' && yb == y_previous))
       continue;             /* do not list register being written to, the
@@ -4500,7 +4513,7 @@ int read_viminfo_register(vir_T *virp, int force)
       return TRUE;              /* too many errors, pretend end-of-file */
     do_it = FALSE;
   }
-  get_yank_register(*str++, FALSE);
+  get_yank_register(*str++, YREG_PUT);
   if (!force && y_current->y_array != NULL)
     do_it = FALSE;
 
@@ -4661,12 +4674,10 @@ char_u get_reg_type(int regname, long *reglen)
     return MCHAR;
   }
 
-  get_clipboard(regname, false);
-
   if (regname != NUL && !valid_yank_reg(regname, FALSE))
     return MAUTO;
 
-  get_yank_register(regname, FALSE);
+  get_yank_register(regname, YREG_PASTE);
 
   if (y_current->y_array != NULL) {
     if (reglen != NULL && y_current->y_type == MBLOCK)
@@ -4722,8 +4733,6 @@ void *get_reg_contents(int regname, int flags)
   if (regname != NUL && !valid_yank_reg(regname, FALSE))
     return NULL;
 
-  get_clipboard(regname, false);
-
   char_u *retval;
   int allocated;
   if (get_spec_reg(regname, &retval, &allocated, FALSE)) {
@@ -4735,7 +4744,7 @@ void *get_reg_contents(int regname, int flags)
     return get_reg_wrap_one_line(vim_strsave(retval), flags);
   }
 
-  get_yank_register(regname, FALSE);
+  get_yank_register(regname, YREG_PASTE);
   if (y_current->y_array == NULL)
     return NULL;
 
@@ -4796,7 +4805,7 @@ static bool init_write_reg(int name, struct yankreg **old_y_previous,
   *old_y_previous = y_previous;
   *old_y_current = y_current;
 
-  get_yank_register(name, true);
+  get_yank_register(name, YREG_YANK);
   if (!y_append && !must_append) {
     free_yank_all();
   }
@@ -5302,7 +5311,7 @@ static void free_register(struct yankreg *reg)
 }
 
 // return target register
-static struct yankreg* adjust_clipboard_name(int *name, bool quiet) {
+static struct yankreg* adjust_clipboard_name(int *name, bool quiet, bool writing) {
   if (*name == '*' || *name == '+') {
     if(!eval_has_provider("clipboard")) {
       if (!quiet) {
@@ -5310,7 +5319,7 @@ static struct yankreg* adjust_clipboard_name(int *name, bool quiet) {
       }
     }
     return &y_regs[*name == '*' ? STAR_REGISTER : PLUS_REGISTER];
-  } else if ((*name == NUL || *name == CB_LATEST) && (cb_flags & CB_UNNAMEDMASK)) {
+  } else if ((*name == NUL) && (cb_flags & CB_UNNAMEDMASK)) {
     if(!eval_has_provider("clipboard")) {
       if (!quiet && !clipboard_didwarn_unnamed) {
         msg((char_u*)"clipboard: provider not available, ignoring clipboard=unnamed[plus]");
@@ -5319,15 +5328,15 @@ static struct yankreg* adjust_clipboard_name(int *name, bool quiet) {
       return NULL;
     }
     struct yankreg* target;
-    if (*name == CB_LATEST) {
-      target = y_current;
-    } else {
-      target = &y_regs[0];
-    }
     if (cb_flags & CB_UNNAMEDPLUS) {
       *name = '+';
+      target = &y_regs[STAR_REGISTER];
     } else {
       *name = '*';
+      target = &y_regs[PLUS_REGISTER];
+    }
+    if (writing) {
+      target = y_current;
     }
     return target; // unnamed register
   }
@@ -5335,9 +5344,9 @@ static struct yankreg* adjust_clipboard_name(int *name, bool quiet) {
   return NULL;
 }
 
-static void get_clipboard(int name, bool quiet)
+static void get_clipboard(int name, struct yankreg** target, bool quiet)
 {
-  struct yankreg* reg = adjust_clipboard_name(&name, quiet);
+  struct yankreg* reg = adjust_clipboard_name(&name, quiet, false);
   if (reg == NULL) {
     return;
   }
@@ -5423,6 +5432,7 @@ static void get_clipboard(int name, bool quiet)
     reg->y_width = maxlen-1;
   }
 
+  *target = reg;
   return;
 
 err:
@@ -5439,7 +5449,7 @@ err:
 
 static void set_clipboard(int name)
 {
-  struct yankreg* reg = adjust_clipboard_name(&name, false);
+  struct yankreg* reg = adjust_clipboard_name(&name, false, true);
   if (reg == NULL) {
     return;
   }

test/functional/clipboard/clipboard_provider_spec.lua

@@ -203,7 +203,6 @@ describe('clipboard usage', function()
 
     it('links the "* and unnamed registers', function()
       -- with cb=unnamed, "* and unnamed will be the same register
-      execute('set clipboard=unnamed')
       insert("some words")
       feed('^"*dwdw"*P')
       expect('words')
@@ -215,6 +214,19 @@ describe('clipboard usage', function()
         words
         linewise stuff]])
       end)
+
+    it('does not clobber "0 when pasting', function()
+      insert('a line')
+      feed('yy')
+      execute("let g:test_clip['*'] = ['b line','']")
+      feed('"0pp"0p')
+      expect([[
+        a line
+        a line
+        b line
+        a line]])
+    end)
+
   end)
 
   it('supports :put', function()
@@ -256,4 +268,13 @@ describe('clipboard usage', function()
       [3] = {bold = true, foreground = Screen.colors.SeaGreen}},
       {{bold = true, foreground = Screen.colors.Blue}})
   end)
+
+  it('can paste "* to the commandline', function()
+    insert('s/s/t/')
+    feed('gg"*y$:<c-r>*<cr>')
+    expect('t/s/t/')
+    execute("let g:test_clip['*'] = ['s/s/u']")
+    feed(':<c-r>*<cr>')
+    expect('t/u/t/')
+  end)
 end)