From bf39a85b7764641b4a4f0c452331c8be8cb34a01 Mon Sep 17 00:00:00 2001
From: Sebastian Harl <sh@tokkee.org>
Date: Mon, 6 Jan 2014 11:55:53 +0100
Subject: [PATCH] frontend parser: Added 'len' parameter to sdb_fe_parse().

When greater than (or equal to) zero, this parameter let's the parser parse a
substring of the specified query. This makes it easier to pass in a command
stored in a connection's input string buffer.
---
 src/frontend/parser.c             |  4 ++--
 src/frontend/scanner.l            | 10 ++++++++--
 src/include/frontend/connection.h |  9 +++++----
 src/include/frontend/parser.h     |  2 +-
 t/frontend/parser_test.c          | 23 ++++++++++++-----------
 5 files changed, 28 insertions(+), 20 deletions(-)

diff --git a/src/frontend/parser.c b/src/frontend/parser.c
index 037550f..718ed68 100644
--- a/src/frontend/parser.c
+++ b/src/frontend/parser.c
@@ -40,7 +40,7 @@
  */
 
 sdb_llist_t *
-sdb_fe_parse(const char *query)
+sdb_fe_parse(const char *query, int len)
 {
 	sdb_fe_yyscan_t scanner;
 	sdb_fe_yyextra_t yyextra;
@@ -52,7 +52,7 @@ sdb_fe_parse(const char *query)
 	memset(&yyextra, 0, sizeof(yyextra));
 	yyextra.parsetree = sdb_llist_create();
 
-	scanner = sdb_fe_scanner_init(query, &yyextra);
+	scanner = sdb_fe_scanner_init(query, len, &yyextra);
 	if (! scanner) {
 		sdb_llist_destroy(yyextra.parsetree);
 		return NULL;
diff --git a/src/frontend/scanner.l b/src/frontend/scanner.l
index f300e46..a0c05d8 100644
--- a/src/frontend/scanner.l
+++ b/src/frontend/scanner.l
@@ -97,10 +97,13 @@ identifier	([A-Za-z_][A-Za-z_0-9$]*)
 %%
 
 sdb_fe_yyscan_t
-sdb_fe_scanner_init(const char *str, sdb_fe_yyextra_t *yyext)
+sdb_fe_scanner_init(const char *str, int len, sdb_fe_yyextra_t *yyext)
 {
 	yyscan_t scanner;
 
+	if (! str)
+		return NULL;
+
 	if (sdb_fe_yylex_init(&scanner)) {
 		char errbuf[1024];
 		sdb_log(SDB_LOG_ERR, "frontend: yylex_init failed: %s",
@@ -110,9 +113,12 @@ sdb_fe_scanner_init(const char *str, sdb_fe_yyextra_t *yyext)
 
 	sdb_fe_yyset_extra(yyext, scanner);
 
+	if (len < 0)
+		len = strlen(str);
+
 	/* the newly allocated buffer state (YY_BUFFER_STATE) is stored inside the
 	 * scanner and, thus, will be freed by yylex_destroy */
-	yy_scan_string(str, scanner);
+	sdb_fe_yy_scan_bytes(str, len, scanner);
 	return scanner;
 } /* sdb_fe_scanner_init */
 
diff --git a/src/include/frontend/connection.h b/src/include/frontend/connection.h
index 06f5243..45d377e 100644
--- a/src/include/frontend/connection.h
+++ b/src/include/frontend/connection.h
@@ -108,16 +108,17 @@ sdb_connection_ping(sdb_conn_t *conn);
 
 /*
  * sdb_fe_parse:
- * Parse the query text specified in 'query' and return a list of parse trees
- * (for each command) to be executed by sdb_fe_exec. The list has to be freed
- * by the caller.
+ * Parse the query text specified in 'query' of length 'len' and return a list
+ * of parse trees (for each command) to be executed by sdb_fe_exec. The list
+ * has to be freed by the caller. If 'len' is less than zero, parse the whole
+ * (nul-terminated) string.
  *
  * Returns:
  *  - an sdb_llist_t object of sdb_conn_node_t on success
  *  - NULL in case of an error
  */
 sdb_llist_t *
-sdb_fe_parse(const char *query);
+sdb_fe_parse(const char *query, int len);
 
 /*
  * sdb_fe_exec:
diff --git a/src/include/frontend/parser.h b/src/include/frontend/parser.h
index a80969c..66a1a5c 100644
--- a/src/include/frontend/parser.h
+++ b/src/include/frontend/parser.h
@@ -44,7 +44,7 @@ typedef struct {
 typedef void *sdb_fe_yyscan_t;
 
 sdb_fe_yyscan_t
-sdb_fe_scanner_init(const char *str, sdb_fe_yyextra_t *yyext);
+sdb_fe_scanner_init(const char *str, int len, sdb_fe_yyextra_t *yyext);
 
 void
 sdb_fe_scanner_destroy(sdb_fe_yyscan_t scanner);
diff --git a/t/frontend/parser_test.c b/t/frontend/parser_test.c
index 5895533..8270cb1 100644
--- a/t/frontend/parser_test.c
+++ b/t/frontend/parser_test.c
@@ -38,25 +38,26 @@ START_TEST(test_parse)
 {
 	struct {
 		const char *query;
+		int len;
 		int expected;
 	} golden_data[] = {
 		/* empty commands */
-		{ NULL,                 -1 },
-		{ "",                    0 },
-		{ ";",                   0 },
-		{ ";;",                  0 },
+		{ NULL,                 -1, -1 },
+		{ "",                   -1,  0 },
+		{ ";",                  -1,  0 },
+		{ ";;",                 -1,  0 },
 
 		/* valid commands */
-		{ "LIST",                1 },
-		{ "LIST;",               1 },
+		{ "LIST",               -1,  1 },
+		{ "LIST;",              -1,  1 },
 
 		/* comments */
-		{ "/* some comment */",  0 },
-		{ "-- another comment",  0 },
+		{ "/* some comment */", -1,  0 },
+		{ "-- another comment", -1,  0 },
 
 		/* syntax errors */
-		{ "INVALID",            -1 },
-		{ "/* some incomplete", -1 },
+		{ "INVALID",            -1, -1 },
+		{ "/* some incomplete", -1, -1 },
 	};
 
 	size_t i;
@@ -65,7 +66,7 @@ START_TEST(test_parse)
 	for (i = 0; i < SDB_STATIC_ARRAY_LEN(golden_data); ++i) {
 		_Bool ok;
 
-		check = sdb_fe_parse(golden_data[i].query);
+		check = sdb_fe_parse(golden_data[i].query, golden_data[i].len);
 		if (golden_data[i].expected < 0)
 			ok = check == 0;
 		else
-- 
2.30.2