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lib: Cleanup parser memory management

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Free as appropriate. Additionally add new type
of node to demark graph head (START_GN).

Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>
This commit is contained in:
Quentin Young 2016-07-27 04:17:51 +00:00
parent eceb106640
commit 5a5d576b34
4 changed files with 95 additions and 68 deletions
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36
lib/command_graph.c
View File

@ -32,18 +32,18 @@ cmp_node(struct graph_node *first, struct graph_node *second)
if (first->type != second->type) return 0;
switch (first->type) {
case WORD_GN: // words and variables are equal if their
case VARIABLE_GN: // text value is equal
case WORD_GN:
case VARIABLE_GN:
if (first->text && second->text) {
if (strcmp(first->text, second->text)) return 0;
}
else if (first->text != second->text) return 0;
break;
case RANGE_GN: // ranges are equal if their bounds are equal
case RANGE_GN:
if (first->min != second->min || first->max != second->max)
return 0;
break;
case NUMBER_GN: // numbers are equal if their values are equal
case NUMBER_GN:
if (first->value != second->value) return 0;
break;
/* selectors and options should be equal if all paths are equal,
@ -53,8 +53,10 @@ cmp_node(struct graph_node *first, struct graph_node *second)
case SELECTOR_GN:
case OPTION_GN:
return 0;
// end nodes are always considered equal, since each node may only
// have one at a time
/* end nodes are always considered equal, since each node may only
* have one at a time
*/
case START_GN:
case END_GN:
default:
break;
@ -66,10 +68,12 @@ cmp_node(struct graph_node *first, struct graph_node *second)
struct graph_node *
new_node(enum graph_node_type type)
{
struct graph_node *node = malloc(sizeof(struct graph_node));
struct graph_node *node =
XMALLOC(MTYPE_CMD_TOKENS, sizeof(struct graph_node));
node->type = type;
node->children = vector_init(VECTOR_MIN_SIZE);
node->is_root = 0;
node->is_start = 0;
node->end = NULL;
node->text = NULL;
node->value = 0;
@ -80,6 +84,18 @@ new_node(enum graph_node_type type)
return node;
}
void
free_node (struct graph_node *node)
{
if (!node) return;
free_node (node->end);
vector_free (node->children);
free (node->text);
free (node->arg);
free (node->element);
free (node);
}
char *
describe_node(struct graph_node *node, char* buffer, unsigned int bufsize)
{
@ -114,6 +130,9 @@ describe_node(struct graph_node *node, char* buffer, unsigned int bufsize)
case END_GN:
snprintf(buffer, bufsize, "END");
break;
case START_GN:
snprintf(buffer, bufsize, "START");
break;
default:
snprintf(buffer, bufsize, "ERROR");
}
@ -146,3 +165,4 @@ walk_graph(struct graph_node *start, int level)
else
fprintf(stderr, "\n");
}

11
lib/command_graph.h
View File

@ -16,6 +16,7 @@ enum graph_node_type
SELECTOR_GN,
OPTION_GN,
NUL_GN,
START_GN,
END_GN
};
@ -37,14 +38,14 @@ struct graph_node
};
/*
* Adds a child to a node.
* If the node already has the exact same child, nothing is done. This is
* decided with cmp_node.
* Adds a node as a child of another node.
* If the new parent has a child that is equal to the prospective child, as
* determined by cmp_node, then a pointer to the existing node is returned and
* the prospective child is not added. Otherwise the return value is NULL.
*
* @param[in] parent node
* @param[in] child node
* @return the new child, or the existing child if the parent already has the
* new child
* @return pointer to child if it is added, pointer to existing child otherwise
*/
extern struct graph_node *
add_node(struct graph_node *, struct graph_node *);

96
lib/command_parse.y
View File

@ -18,6 +18,7 @@ extern void yyerror(const char *);
%code requires {
#include "command.h"
#include "command_graph.h"
#include "memory.h"
}
%code provides {
extern void
@ -50,14 +51,14 @@ struct graph_node *selnode_start, // start node for selector set
struct cmd_element *command; // command we're parsing
%}
%token <node> WORD
%token <node> IPV4
%token <node> IPV4_PREFIX
%token <node> IPV6
%token <node> IPV6_PREFIX
%token <node> VARIABLE
%token <node> RANGE
%token <node> NUMBER
%token <string> WORD
%token <string> IPV4
%token <string> IPV4_PREFIX
%token <string> IPV6
%token <string> IPV6_PREFIX
%token <string> VARIABLE
%token <string> RANGE
%token <integer> NUMBER
%type <node> start
%type <node> sentence_root
@ -80,44 +81,45 @@ struct cmd_element *command; // command we're parsing
start: sentence_root
cmd_token_seq
{
// this should never happen...
if (currnode->type == END_GN)
yyerror("Unexpected leaf");
// create function pointer node
// create leaf node
struct graph_node *end = new_node(END_GN);
end->element = command;
// ensure there are no END_GN children
for (unsigned int i = 0; i < vector_active(currnode->children); i++)
{
struct graph_node *child = vector_slot(currnode->children, i);
if (child->type == END_GN)
yyerror("Duplicate command.");
}
// add node
end = add_node(currnode, end);
if (add_node(currnode, end) != end)
{
yyerror("Duplicate command.");
YYABORT;
}
}
sentence_root: WORD
{
$$ = new_node(WORD_GN);
$$->text = strdup(yylval.string);
fprintf(stderr, ">>>>>>>> YYLVAL.STRING: %s\n", yylval.string);
fprintf(stderr, ">>>>>>>> TEXT: %s\n", $$->text);
struct graph_node *root = new_node(WORD_GN);
root->text = XSTRDUP(MTYPE_CMD_TOKENS, $1);
currnode = $$;
currnode->is_root = 1;
currnode = add_node(startnode, currnode);
currnode = add_node(startnode, root);
if (currnode != root)
free (root);
free ($1);
$$ = currnode;
};
/* valid top level tokens */
cmd_token:
placeholder_token
{ currnode = add_node(currnode, $1); }
{
currnode = add_node(currnode, $1);
if (currnode != $1)
free_node ($1);
}
| literal_token
{ currnode = add_node(currnode, $1); }
{
currnode = add_node(currnode, $1);
if (currnode != $1)
free_node ($1);
}
/* selectors and options are subgraphs with start and end nodes */
| selector
{
@ -142,37 +144,44 @@ placeholder_token:
IPV4
{
$$ = new_node(IPV4_GN);
$$->text = strdup(yylval.string);
$$->text = XSTRDUP(MTYPE_CMD_TOKENS, $1);
free ($1);
}
| IPV4_PREFIX
{
$$ = new_node(IPV4_PREFIX_GN);
$$->text = strdup(yylval.string);
$$->text = XSTRDUP(MTYPE_CMD_TOKENS, $1);
free ($1);
}
| IPV6
{
$$ = new_node(IPV6_GN);
$$->text = strdup(yylval.string);
$$->text = XSTRDUP(MTYPE_CMD_TOKENS, $1);
free ($1);
}
| IPV6_PREFIX
{
$$ = new_node(IPV6_PREFIX_GN);
$$->text = strdup(yylval.string);
$$->text = XSTRDUP(MTYPE_CMD_TOKENS, $1);
free ($1);
}
| VARIABLE
{
$$ = new_node(VARIABLE_GN);
$$->text = strdup(yylval.string);
$$->text = XSTRDUP(MTYPE_CMD_TOKENS, $1);
free ($1);
}
| RANGE
{
$$ = new_node(RANGE_GN);
$$->text = strdup(yylval.string);
$$->text = XSTRDUP(MTYPE_CMD_TOKENS, $1);
// get the numbers out
strsep(&yylval.string, "(-)");
$$->min = atoi( strsep(&yylval.string, "(-)") );
$$->max = atoi( strsep(&yylval.string, "(-)") );
free ($1);
}
;
@ -180,9 +189,8 @@ literal_token:
WORD
{
$$ = new_node(WORD_GN);
$$->text = strdup(yylval.string);
fprintf(stderr, ">>>>>>>> YYLVAL.STRING: %s\n", yylval.string);
fprintf(stderr, ">>>>>>>> TEXT: %s\n", $$->text);
$$->text = XSTRDUP(MTYPE_CMD_TOKENS, $1);
free ($1);
}
| NUMBER
{
@ -300,8 +308,7 @@ option_token:
void yyerror(char const *message) {
// fail on bad parse
printf("Grammar error: %s\n", message);
exit(EXIT_FAILURE);
fprintf(stderr, "Grammar error: %s\n", message);
}
struct graph_node *
@ -310,7 +317,8 @@ parse_command_format(struct graph_node *start, struct cmd_element *cmd)
fprintf(stderr, "parsing: %s\n", cmd->string);
/* clear state pointers */
startnode = currnode = seqhead = NULL;
startnode = start;
currnode = seqhead = NULL;
selnode_start = selnode_end = NULL;
optnode_start = optnode_end = NULL;
@ -320,8 +328,6 @@ parse_command_format(struct graph_node *start, struct cmd_element *cmd)
command = cmd;
// make flex read from a string
set_buffer_string(command->string);
// initialize the start node of this command dfa
startnode = start;
// parse command into DFA
yyparse();
// startnode points to command DFA

2
lib/grammar_sandbox.c
View File

@ -101,7 +101,7 @@ DEFUN (grammar_test_match,
void grammar_sandbox_init(void);
void grammar_sandbox_init() {
fprintf(stderr, "reinitializing graph\n");
nodegraph = new_node(NUL_GN);
nodegraph = new_node(START_GN);
install_element (ENABLE_NODE, &grammar_test_cmd);
install_element (ENABLE_NODE, &grammar_test_show_cmd);
install_element (ENABLE_NODE, &grammar_test_match_cmd);