From 1b272c7d47390077eee0a0638329b1a7df521329 Mon Sep 17 00:00:00 2001
From: Jeremy Kerr <jk@ozlabs.org>
Date: Fri, 24 Jan 2014 14:40:46 +0800
Subject: [PATCH] discover/grub2: Add support for for-loops

GRUB2 syntax allows for for-loops; this change adds supoprt in the
parser grammar and script execution code to implement them. In the
execution code, we simply update the for-loop variable and re-execute
the body statements.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
---
 discover/grub2/grub2.h  | 13 +++++++++++++
 discover/grub2/parser.y | 19 +++++++++++++++++++
 discover/grub2/script.c | 23 +++++++++++++++++++++++
 3 files changed, 55 insertions(+)

diff --git a/discover/grub2/grub2.h b/discover/grub2/grub2.h
index 6166289..e79bf41 100644
--- a/discover/grub2/grub2.h
+++ b/discover/grub2/grub2.h
@@ -83,6 +83,13 @@ struct grub2_statement_function {
 	struct grub2_statements	*body;
 };
 
+struct grub2_statement_for {
+	struct grub2_statement	st;
+	struct grub2_word	*var;
+	struct grub2_argv	*list;
+	struct grub2_statements	*body;
+};
+
 struct grub2_script {
 	struct grub2_statements		*statements;
 	struct list			environment;
@@ -125,6 +132,10 @@ struct grub2_statement *create_statement_block(struct grub2_parser *parser,
 struct grub2_statement *create_statement_function(struct grub2_parser *parser,
 		struct grub2_word *name, struct grub2_statements *body);
 
+struct grub2_statement *create_statement_for(struct grub2_parser *parser,
+		struct grub2_word *var, struct grub2_argv *list,
+		struct grub2_statements *body);
+
 struct grub2_word *create_word_text(struct grub2_parser *parser,
 		const char *text);
 
@@ -153,6 +164,8 @@ int statement_menuentry_execute(struct grub2_script *script,
 		struct grub2_statement *statement);
 int statement_function_execute(struct grub2_script *script,
 		struct grub2_statement *statement);
+int statement_for_execute(struct grub2_script *script,
+		struct grub2_statement *statement);
 
 struct grub2_script *create_script(struct grub2_parser *parser,
 		struct discover_context *ctx);
diff --git a/discover/grub2/parser.y b/discover/grub2/parser.y
index 0beddd6..23bf427 100644
--- a/discover/grub2/parser.y
+++ b/discover/grub2/parser.y
@@ -130,6 +130,12 @@ statement:
 		/* we just flatten everything */
 		$$ = create_statement_block(parser, $6);
 	}
+	| "for" TOKEN_DELIM word TOKEN_DELIM "in" TOKEN_DELIM words TOKEN_EOL
+		"do" sep
+		statements
+		"done" {
+		$$ = create_statement_for(parser, $3, $7, $11);
+	}
 
 words:	word {
 		$$ = create_argv(parser);
@@ -243,6 +249,19 @@ struct grub2_statement *create_statement_function(struct grub2_parser *parser,
 	return &stmt->st;
 }
 
+struct grub2_statement *create_statement_for(struct grub2_parser *parser,
+		struct grub2_word *var, struct grub2_argv *list,
+		struct grub2_statements *body)
+{
+	struct grub2_statement_for *stmt =
+		talloc(parser, struct grub2_statement_for);
+	stmt->st.exec = statement_for_execute;
+	stmt->var = var;
+	stmt->list = list;
+	stmt->body = body;
+	return &stmt->st;
+}
+
 void statement_append(struct grub2_statements *stmts,
 		struct grub2_statement *stmt)
 {
diff --git a/discover/grub2/script.c b/discover/grub2/script.c
index bfca607..0618297 100644
--- a/discover/grub2/script.c
+++ b/discover/grub2/script.c
@@ -19,6 +19,8 @@
 	container_of(stmt, struct grub2_statement_menuentry, st)
 #define to_stmt_function(stmt) \
 	container_of(stmt, struct grub2_statement_function, st)
+#define to_stmt_for(stmt) \
+	container_of(stmt, struct grub2_statement_for, st)
 #define to_stmt_conditional(stmt) \
 	container_of(stmt, struct grub2_statement_conditional, st)
 
@@ -401,6 +403,27 @@ int statement_function_execute(struct grub2_script *script,
 	return 0;
 }
 
+int statement_for_execute(struct grub2_script *script,
+		struct grub2_statement *statement)
+{
+	struct grub2_statement_for *st = to_stmt_for(statement);
+	const char *varname;
+	int i, rc = 0;
+
+	if (st->var->type == GRUB2_WORD_VAR)
+		expand_var(script, st->var);
+	varname = st->var->text;
+
+	process_expansions(script, st->list);
+
+	for (i = 0; i < st->list->argc; ++i) {
+		script_env_set(script, varname, st->list->argv[i]);
+		rc = statements_execute(script, st->body);
+	}
+
+	return rc;
+}
+
 static void init_env(struct grub2_script *script)
 {
 	struct env_entry *env;
-- 
2.39.2