Support "insert into ... returning ..." in sqlite-execute

* doc/lispref/text.texi (Database): Mention it.
* src/sqlite.c (Fsqlite_execute): Support syntax like "insert into
... returning ..." (bug#58390).

2 files changed, 70 insertions, 59 deletions

diff --git a/doc/lispref/text.texi b/doc/lispref/text.texi
index 8b859042ad0..e0768721d94 100644
--- a/doc/lispref/text.texi
+++ b/doc/lispref/text.texi
@@ -5321,9 +5321,12 @@ This has exactly the same effect as the previous example, but is more
 efficient and safer (because it doesn't involve any string parsing or
 interpolation).
 
-@code{sqlite-execute} returns the number of affected rows.  For
-instance, an @samp{insert} statement will return @samp{1}, whereas an
-@samp{update} statement may return zero or a higher number.
+@code{sqlite-execute} usually returns the number of affected rows.
+For instance, an @samp{insert} statement will typically return
+@samp{1}, whereas an @samp{update} statement may return zero or a
+higher number.  However, when using @acronym{SQL} statements like
+@samp{insert into ... returning ...} and the like, the values
+specified by @samp{returning ...} will be returned instead.
 
 Strings in SQLite are, by default, stored as @code{utf-8}, and
 selecting a text column will decode the string using that charset.
diff --git a/src/sqlite.c b/src/sqlite.c
index 7af3760eb4c..65b1dc492f6 100644
--- a/src/sqlite.c
+++ b/src/sqlite.c
@@ -377,6 +377,50 @@ bind_values (sqlite3 *db, sqlite3_stmt *stmt, Lisp_Object values)
   return NULL;
 }
 
+static Lisp_Object
+row_to_value (sqlite3_stmt *stmt)
+{
+  int len = sqlite3_column_count (stmt);
+  Lisp_Object values = Qnil;
+
+  for (int i = 0; i < len; ++i)
+    {
+      Lisp_Object v = Qnil;
+
+      switch (sqlite3_column_type (stmt, i))
+	{
+	case SQLITE_INTEGER:
+	  v = make_int (sqlite3_column_int64 (stmt, i));
+	  break;
+
+	case SQLITE_FLOAT:
+	  v = make_float (sqlite3_column_double (stmt, i));
+	  break;
+
+	case SQLITE_BLOB:
+	  v = make_unibyte_string (sqlite3_column_blob (stmt, i),
+				   sqlite3_column_bytes (stmt, i));
+	  break;
+
+	case SQLITE_NULL:
+	  v = Qnil;
+	  break;
+
+	case SQLITE_TEXT:
+	  v =
+	    code_convert_string_norecord
+	    (make_unibyte_string ((const char *)sqlite3_column_text (stmt, i),
+				  sqlite3_column_bytes (stmt, i)),
+	     Qutf_8, false);
+	  break;
+	}
+
+      values = Fcons (v, values);
+    }
+
+  return Fnreverse (values);
+}
+
 DEFUN ("sqlite-execute", Fsqlite_execute, Ssqlite_execute, 2, 3, 0,
        doc: /* Execute a non-select SQL statement.
 If VALUES is non-nil, it should be a vector or a list of values
@@ -393,7 +437,6 @@ Value is the number of affected rows.  */)
     xsignal1 (Qerror, build_string ("VALUES must be a list or a vector"));
 
   sqlite3 *sdb = XSQLITE (db)->db;
-  Lisp_Object retval = Qnil;
   const char *errmsg = NULL;
   Lisp_Object encoded = encode_string (query);
   sqlite3_stmt *stmt = NULL;
@@ -426,66 +469,31 @@ Value is the number of affected rows.  */)
     }
 
   ret = sqlite3_step (stmt);
-  sqlite3_finalize (stmt);
-  if (ret != SQLITE_OK && ret != SQLITE_DONE)
-    {
-      errmsg = sqlite3_errmsg (sdb);
-      goto exit;
-    }
 
-  retval = make_fixnum (sqlite3_changes (sdb));
-
- exit:
-  if (errmsg != NULL)
-    xsignal1 (ret == SQLITE_LOCKED || ret == SQLITE_BUSY?
-	      Qsqlite_locked_error: Qerror,
-	      build_string (errmsg));
-
-  return retval;
-}
-
-static Lisp_Object
-row_to_value (sqlite3_stmt *stmt)
-{
-  int len = sqlite3_column_count (stmt);
-  Lisp_Object values = Qnil;
-
-  for (int i = 0; i < len; ++i)
+  if (ret == SQLITE_ROW)
     {
-      Lisp_Object v = Qnil;
-
-      switch (sqlite3_column_type (stmt, i))
-	{
-	case SQLITE_INTEGER:
-	  v = make_int (sqlite3_column_int64 (stmt, i));
-	  break;
-
-	case SQLITE_FLOAT:
-	  v = make_float (sqlite3_column_double (stmt, i));
-	  break;
+      Lisp_Object data = Qnil;
+      do
+	data = Fcons (row_to_value (stmt), data);
+      while (sqlite3_step (stmt) == SQLITE_ROW);
 
-	case SQLITE_BLOB:
-	  v = make_unibyte_string (sqlite3_column_blob (stmt, i),
-				   sqlite3_column_bytes (stmt, i));
-	  break;
-
-	case SQLITE_NULL:
-	  v = Qnil;
-	  break;
-
-	case SQLITE_TEXT:
-	  v =
-	    code_convert_string_norecord
-	    (make_unibyte_string ((const char *)sqlite3_column_text (stmt, i),
-				  sqlite3_column_bytes (stmt, i)),
-	     Qutf_8, false);
-	  break;
-	}
-
-      values = Fcons (v, values);
+      sqlite3_finalize (stmt);
+      return Fnreverse (data);
     }
+  else if (ret == SQLITE_OK || ret == SQLITE_DONE)
+    {
+      Lisp_Object rows = make_fixnum (sqlite3_changes (sdb));
+      sqlite3_finalize (stmt);
+      return rows;
+    }
+  else
+    errmsg = sqlite3_errmsg (sdb);
 
-  return Fnreverse (values);
+ exit:
+  sqlite3_finalize (stmt);
+  xsignal1 (ret == SQLITE_LOCKED || ret == SQLITE_BUSY?
+	    Qsqlite_locked_error: Qerror,
+	    build_string (errmsg));
 }
 
 static Lisp_Object