discover/grub2: Implement 'elif'

Rather than just having one conditional in an if statement, we use a
list of conditionals instead. This allows us to implement elif.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

3 files changed, 31 insertions, 9 deletions

diff --git a/discover/grub2/grub2.h b/discover/grub2/grub2.h
index 7f4a834..c7f43de 100644
--- a/discover/grub2/grub2.h
+++ b/discover/grub2/grub2.h
@@ -68,7 +68,7 @@ struct grub2_statement_conditional {
 
 struct grub2_statement_if {
 	struct grub2_statement	st;
-	struct grub2_statement	*conditional;
+	struct grub2_statements	*conditionals;
 	struct grub2_statements	*else_case;
 };
 
@@ -114,6 +114,7 @@ struct grub2_statement *create_statement_conditional(
 
 struct grub2_statement *create_statement_if(struct grub2_parser *parser,
 		struct grub2_statement *conditional,
+		struct grub2_statements *elifs,
 		struct grub2_statements *else_case);
 
 struct grub2_statement *create_statement_block(struct grub2_parser *parser,
diff --git a/discover/grub2/parser.y b/discover/grub2/parser.y
index 52dac9c..81856df 100644
--- a/discover/grub2/parser.y
+++ b/discover/grub2/parser.y
@@ -48,6 +48,8 @@ static void yyerror(struct grub2_parser *, char const *s);
 %type <statement>	statement
 %type <statements>	statements
 %type <statement>	conditional
+%type <statement>	elif
+%type <statements>	elifs
 %type <argv>		words
 %type <word>		word
 
@@ -80,6 +82,18 @@ conditional: statement TOKEN_EOL "then" TOKEN_EOL statements {
 		$$ = create_statement_conditional(parser, $1, $5);
 	}
 
+elif: "elif" TOKEN_DELIM conditional {
+		$$ = $3;
+      }
+
+elifs: /* empty */ {
+		$$ = create_statements(parser);
+	}
+	| elifs elif {
+		statement_append($1, $2);
+		$$ = $1;
+	}
+
 statement:
 	words {
 		   $$ = create_statement_simple(parser, $1);
@@ -87,14 +101,15 @@ statement:
 	| '{' statements '}' {
 		$$ = create_statement_block(parser, $2);
 	}
-	| "if" TOKEN_DELIM conditional "fi" {
-		$$ = create_statement_if(parser, $3, NULL);
+	| "if" TOKEN_DELIM conditional elifs "fi" {
+		$$ = create_statement_if(parser, $3, $4, NULL);
 	}
 	| "if" TOKEN_DELIM conditional
+		elifs
 		"else" TOKEN_EOL
 		statements
 		"fi" {
-		$$ = create_statement_if(parser, $3, $6);
+		$$ = create_statement_if(parser, $3, $4, $7);
 	}
 	| "function" TOKEN_DELIM word TOKEN_DELIM '{' statements '}' {
 		$$ = create_statement_function(parser, $3, $6);
@@ -178,13 +193,17 @@ struct grub2_statement *create_statement_conditional(
 
 struct grub2_statement *create_statement_if(struct grub2_parser *parser,
 		struct grub2_statement *conditional,
+		struct grub2_statements *elifs,
 		struct grub2_statements *else_case)
 {
 	struct grub2_statement_if *stmt =
 		talloc(parser, struct grub2_statement_if);
+
+	list_add(&elifs->list, &conditional->list);
+
 	stmt->st.type = STMT_TYPE_IF;
 	stmt->st.exec = statement_if_execute;
-	stmt->conditional = conditional;
+	stmt->conditionals = elifs;
 	stmt->else_case = else_case;
 	return &stmt->st;
 }
diff --git a/discover/grub2/script.c b/discover/grub2/script.c
index c0d6e1a..239ae38 100644
--- a/discover/grub2/script.c
+++ b/discover/grub2/script.c
@@ -277,10 +277,12 @@ int statement_if_execute(struct grub2_script *script,
 	bool executed;
 	int rc;
 
-	conditional = st->conditional;
-
-	rc = statement_conditional_execute(script,
-			conditional, &executed);
+	list_for_each_entry(&st->conditionals->list, conditional, list) {
+		rc = statement_conditional_execute(script,
+				conditional, &executed);
+		if (executed)
+			break;
+	}
 
 	if (!executed && st->else_case)
 		rc = statements_execute(script, st->else_case);