Re-use the parse tree generated during error detection for execution

Prior to this fix, read_ni would use parse_util_detect_errors
to lint the script to run, and then parser_t::eval() to execute it.
Both functions would parse the script into a parse tree. This allows
us to re-use the parse tree, improving perfomance.

3 files changed, 13 insertions, 6 deletions

diff --git a/src/parse_util.cpp b/src/parse_util.cpp
index a528c898..628e86c5 100644
--- a/src/parse_util.cpp
+++ b/src/parse_util.cpp
@@ -1287,7 +1287,7 @@ parser_test_error_bits_t parse_util_detect_errors_in_argument(const parse_node_t
     return err;
 }
 
-parser_test_error_bits_t parse_util_detect_errors(const wcstring &buff_src, parse_error_list_t *out_errors, bool allow_incomplete)
+parser_test_error_bits_t parse_util_detect_errors(const wcstring &buff_src, parse_error_list_t *out_errors, bool allow_incomplete, parse_node_tree_t *out_tree)
 {
     parse_node_tree_t node_tree;
     parse_error_list_t parse_errors;
@@ -1546,10 +1546,15 @@ parser_test_error_bits_t parse_util_detect_errors(const wcstring &buff_src, pars
     if (has_unclosed_block || has_unclosed_quote)
         res |= PARSER_TEST_INCOMPLETE;
 
-    if (out_errors)
+    if (out_errors != NULL)
     {
         out_errors->swap(parse_errors);
     }
+    
+    if (out_tree != NULL)
+    {
+        out_tree->swap(node_tree);
+    }
 
     return res;
 
diff --git a/src/parse_util.h b/src/parse_util.h
index 9bafd8e0..26f47268 100644
--- a/src/parse_util.h
+++ b/src/parse_util.h
@@ -171,8 +171,9 @@ wcstring parse_util_escape_string_with_quote(const wcstring &cmd, wchar_t quote)
 /** Given a string, parse it as fish code and then return the indents. The return value has the same size as the string */
 std::vector<int> parse_util_compute_indents(const wcstring &src);
 
-/** Given a string, detect parse errors in it. If allow_incomplete is set, then if the string is incomplete (e.g. an unclosed quote), an error is not returned and the PARSER_TEST_INCOMPLETE bit is set in the return value. If allow_incomplete is not set, then incomplete strings result in an error. */
-parser_test_error_bits_t parse_util_detect_errors(const wcstring &buff_src, parse_error_list_t *out_errors = NULL, bool allow_incomplete = true);
+/** Given a string, detect parse errors in it. If allow_incomplete is set, then if the string is incomplete (e.g. an unclosed quote), an error is not returned and the PARSER_TEST_INCOMPLETE bit is set in the return value. If allow_incomplete is not set, then incomplete strings result in an error. If out_tree is not NULL, the resulting tree is returned by reference. */
+class parse_node_tree_t;
+parser_test_error_bits_t parse_util_detect_errors(const wcstring &buff_src, parse_error_list_t *out_errors = NULL, bool allow_incomplete = true, parse_node_tree_t *out_tree = NULL);
 
 /**
    Test if this argument contains any errors. Detected errors include syntax errors in command substitutions, improperly escaped characters and improper use of the variable expansion operator.
diff --git a/src/reader.cpp b/src/reader.cpp
index 1b4f8d2d..3998e5a0 100644
--- a/src/reader.cpp
+++ b/src/reader.cpp
@@ -4258,9 +4258,10 @@ static int read_ni(int fd, const io_chain_t &io)
         }
 
         parse_error_list_t errors;
-        if (! parse_util_detect_errors(str, &errors, false /* do not accept incomplete */))
+        parse_node_tree_t tree;
+        if (! parse_util_detect_errors(str, &errors, false /* do not accept incomplete */, &tree))
         {
-            parser.eval(str, io, TOP);
+            parser.eval_acquiring_tree(str, io, TOP, moved_ref<parse_node_tree_t>(tree));
         }
         else
         {