vim-patch:9.0.0430: cannot use repeat() with a blob

Problem:    Cannot use repeat() with a blob.
Solution:   Implement blob repeat. (closes vim/vim#11090)

https://github.com/vim/vim/commit/375141e1f80dced9be738568a3418f65813f4a2f

Co-authored-by: Bakudankun <bakudankun@gmail.com>

5 files changed, 52 insertions, 6 deletions

diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index b194a104f7..7fab2ac6ff 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -380,7 +380,8 @@ remove({blob}, {idx} [, {end}])	Number/Blob
 					remove bytes {idx}-{end} from {blob}
 remove({dict}, {key})		any	remove entry {key} from {dict}
 rename({from}, {to})		Number	rename (move) file from {from} to {to}
-repeat({expr}, {count})		String	repeat {expr} {count} times
+repeat({expr}, {count})		List/Blob/String
+					repeat {expr} {count} times
 resolve({filename})		String	get filename a shortcut points to
 reverse({list})			List	reverse {list} in-place
 round({expr})			Float	round off {expr}
@@ -6420,8 +6421,8 @@ repeat({expr}, {count})					*repeat()*
 		result.  Example: >
 			:let separator = repeat('-', 80)
 <		When {count} is zero or negative the result is empty.
-		When {expr} is a |List| the result is {expr} concatenated
-		{count} times.  Example: >
+		When {expr} is a |List| or a |Blob| the result is {expr}
+		concatenated {count} times.  Example: >
 			:let longlist = repeat(['a', 'b'], 3)
 <		Results in ['a', 'b', 'a', 'b', 'a', 'b'].
 
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index b81384266c..0fbf31a8cd 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -1613,7 +1613,7 @@ void set_var_lval(lval_T *lp, char *endp, typval_T *rettv, int copy, const bool
           lp->ll_n2 = tv_blob_len(lp->ll_blob) - 1;
         }
 
-        if (tv_blob_set_range(lp->ll_blob, lp->ll_n1, lp->ll_n2, rettv) == FAIL) {
+        if (tv_blob_set_range(lp->ll_blob, (int)lp->ll_n1, (int)lp->ll_n2, rettv) == FAIL) {
           return;
         }
       } else {
@@ -4938,6 +4938,8 @@ theend:
   return retval;
 }
 
+/// "function()" function
+/// "funcref()" function
 void common_function(typval_T *argvars, typval_T *rettv, bool is_funcref)
 {
   char *s;
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index 5da6233e38..4208c5ca46 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -5976,6 +5976,37 @@ static void f_repeat(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     while (n-- > 0) {
       tv_list_extend(rettv->vval.v_list, argvars[0].vval.v_list, NULL);
     }
+  } else if (argvars[0].v_type == VAR_BLOB) {
+    tv_blob_alloc_ret(rettv);
+    if (argvars[0].vval.v_blob == NULL || n <= 0) {
+      return;
+    }
+
+    const int slen = argvars[0].vval.v_blob->bv_ga.ga_len;
+    const int len = (int)(slen * n);
+    if (len <= 0) {
+      return;
+    }
+
+    ga_grow(&rettv->vval.v_blob->bv_ga, len);
+
+    rettv->vval.v_blob->bv_ga.ga_len = len;
+
+    int i;
+    for (i = 0; i < slen; i++) {
+      if (tv_blob_get(argvars[0].vval.v_blob, i) != 0) {
+        break;
+      }
+    }
+
+    if (i == slen) {
+      // No need to copy since all bytes are already zero
+      return;
+    }
+
+    for (i = 0; i < n; i++) {
+      tv_blob_set_range(rettv->vval.v_blob, i * slen, (i + 1) * slen - 1, argvars);
+    }
   } else {
     rettv->v_type = VAR_STRING;
     rettv->vval.v_string = NULL;
diff --git a/src/nvim/eval/typval.c b/src/nvim/eval/typval.c
index 6037536548..7d49049b0c 100644
--- a/src/nvim/eval/typval.c
+++ b/src/nvim/eval/typval.c
@@ -2743,14 +2743,14 @@ int tv_blob_check_range(int bloblen, varnumber_T n1, varnumber_T n2, bool quiet)
 /// Set bytes "n1" to "n2" (inclusive) in "dest" to the value of "src".
 /// Caller must make sure "src" is a blob.
 /// Returns FAIL if the number of bytes does not match.
-int tv_blob_set_range(blob_T *dest, long n1, long n2, typval_T *src)
+int tv_blob_set_range(blob_T *dest, int n1, int n2, typval_T *src)
 {
   if (n2 - n1 + 1 != tv_blob_len(src->vval.v_blob)) {
     emsg(_("E972: Blob value does not have the right number of bytes"));
     return FAIL;
   }
 
-  for (int il = (int)n1, ir = 0; il <= (int)n2; il++) {
+  for (int il = n1, ir = 0; il <= n2; il++) {
     tv_blob_set(dest, il, tv_blob_get(src->vval.v_blob, ir++));
   }
   return OK;
diff --git a/src/nvim/testdir/test_blob.vim b/src/nvim/testdir/test_blob.vim
index 310582240c..2c145f2019 100644
--- a/src/nvim/testdir/test_blob.vim
+++ b/src/nvim/testdir/test_blob.vim
@@ -715,6 +715,18 @@ func Test_blob2string()
   call assert_equal(v, string(b))
 endfunc
 
+func Test_blob_repeat()
+  call assert_equal(0z, repeat(0z00, 0))
+  call assert_equal(0z00, repeat(0z00, 1))
+  call assert_equal(0z0000, repeat(0z00, 2))
+  call assert_equal(0z00000000, repeat(0z0000, 2))
+
+  call assert_equal(0z, repeat(0z12, 0))
+  call assert_equal(0z, repeat(0z1234, 0))
+  call assert_equal(0z1234, repeat(0z1234, 1))
+  call assert_equal(0z12341234, repeat(0z1234, 2))
+endfunc
+
 " Test for blob allocation failure
 func Test_blob_alloc_failure()
   CheckFunction test_alloc_fail