diff options
| -rw-r--r-- | bfs.c | 185 |
1 files changed, 133 insertions, 52 deletions
@@ -88,6 +88,53 @@ static expression *new_expression(eval_fn *eval) { } /** + * -true test. + */ +static bool eval_true(const expression *expr, eval_state *state) { + return true; +} + +/** + * Singleton true expression instance. + */ +static expression expr_true = { + .lhs = NULL, + .rhs = NULL, + .eval = eval_true, + .idata = 0, + .sdata = NULL, +}; + +/** + * -false test. + */ +static bool eval_false(const expression *expr, eval_state *state) { + return false; +} + +/** + * Singleton false expression instance. + */ +static expression expr_false = { + .lhs = NULL, + .rhs = NULL, + .eval = eval_false, + .idata = 0, + .sdata = NULL, +}; + +/** + * Free an expression. + */ +static void free_expression(expression *expr) { + if (expr && expr != &expr_true && expr != &expr_false) { + free_expression(expr->lhs); + free_expression(expr->rhs); + free(expr); + } +} + +/** * Create a new expression with integer data. */ static expression *new_expression_idata(eval_fn *eval, int idata) { @@ -112,37 +159,33 @@ static expression *new_expression_sdata(eval_fn *eval, const char *sdata) { /** * Create a new unary expression. */ -static expression *new_expression_unary(expression *rhs, eval_fn *eval) { +static expression *new_unary_expression(expression *rhs, eval_fn *eval) { expression *expr = new_expression(eval); - if (expr) { - expr->rhs = rhs; - expr->eval = eval; + if (!expr) { + free_expression(rhs); + return NULL; } + + expr->rhs = rhs; + expr->eval = eval; return expr; } /** * Create a new binary expression. */ -static expression *new_expression_binary(expression *lhs, expression *rhs, eval_fn *eval) { +static expression *new_binary_expression(expression *lhs, expression *rhs, eval_fn *eval) { expression *expr = new_expression(eval); - if (expr) { - expr->lhs = lhs; - expr->rhs = rhs; - expr->eval = eval; + if (!expr) { + free_expression(rhs); + free_expression(lhs); + return NULL; } - return expr; -} -/** - * Free an expression. - */ -static void free_expression(expression *expr) { - if (expr) { - free_expression(expr->lhs); - free_expression(expr->rhs); - free(expr); - } + expr->lhs = lhs; + expr->rhs = rhs; + expr->eval = eval; + return expr; } struct cmdline { @@ -240,13 +283,6 @@ static const char *skip_paths(parser_state *state) { } /** - * -false test. - */ -static bool eval_false(const expression *expr, eval_state *state) { - return false; -} - -/** * -prune action. */ static bool eval_prune(const expression *expr, eval_state *state) { @@ -298,13 +334,6 @@ static bool eval_print0(const expression *expr, eval_state *state) { } /** - * -true test. - */ -static bool eval_true(const expression *expr, eval_state *state) { - return true; -} - -/** * -type test. */ static bool eval_type(const expression *expr, eval_state *state) { @@ -315,7 +344,7 @@ static bool eval_type(const expression *expr, eval_state *state) { * Create a new option expression. */ static expression *new_option(parser_state *state) { - return new_expression(eval_true); + return &expr_true; } /** @@ -454,7 +483,7 @@ static expression *parse_literal(parser_state *state) { state->cl->flags |= BFTW_DEPTH; return new_option(state); } else if (strcmp(arg, "-false") == 0) { - return new_test(state, eval_false); + return &expr_false; } else if (strcmp(arg, "-hidden") == 0) { return new_test(state, eval_hidden); } else if (strcmp(arg, "-nohidden") == 0) { @@ -472,7 +501,7 @@ static expression *parse_literal(parser_state *state) { } else if (strcmp(arg, "-prune") == 0) { return new_action(state, eval_prune); } else if (strcmp(arg, "-true") == 0) { - return new_test(state, eval_true); + return &expr_true; } else if (strcmp(arg, "-type") == 0) { return parse_type(state); } else { @@ -489,6 +518,19 @@ static bool eval_not(const expression *expr, eval_state *state) { } /** + * Create a "not" expression. + */ +static expression *new_not_expression(expression *rhs) { + if (rhs == &expr_true) { + return &expr_false; + } else if (rhs == &expr_false) { + return &expr_true; + } else { + return new_unary_expression(rhs, eval_not); + } +} + +/** * FACTOR : "(" EXPR ")" * | "!" FACTOR | "-not" FACTOR * | LITERAL @@ -524,7 +566,7 @@ static expression *parse_factor(parser_state *state) { return NULL; } - return new_expression_unary(factor, eval_not); + return new_not_expression(factor); } else { return parse_literal(state); } @@ -538,6 +580,22 @@ static bool eval_and(const expression *expr, eval_state *state) { } /** + * Create an "and" expression. + */ +static expression *new_and_expression(expression *lhs, expression *rhs) { + if (lhs == &expr_true) { + return rhs; + } else if (lhs == &expr_false) { + free_expression(rhs); + return lhs; + } else if (rhs == &expr_true) { + return lhs; + } else { + return new_binary_expression(lhs, rhs, eval_and); + } +} + +/** * TERM : FACTOR * | TERM FACTOR * | TERM "-a" FACTOR @@ -565,10 +623,11 @@ static expression *parse_term(parser_state *state) { expression *lhs = term; expression *rhs = parse_factor(state); if (!rhs) { + free_expression(lhs); return NULL; } - term = new_expression_binary(lhs, rhs, eval_and); + term = new_and_expression(lhs, rhs); } return term; @@ -582,6 +641,22 @@ static bool eval_or(const expression *expr, eval_state *state) { } /** + * Create an "or" expression. + */ +static expression *new_or_expression(expression *lhs, expression *rhs) { + if (lhs == &expr_true) { + free_expression(rhs); + return lhs; + } else if (lhs == &expr_false) { + return rhs; + } else if (rhs == &expr_false) { + return lhs; + } else { + return new_binary_expression(lhs, rhs, eval_or); + } +} + +/** * CLAUSE : TERM * | CLAUSE "-o" TERM * | CLAUSE "-or" TERM @@ -604,10 +679,11 @@ static expression *parse_clause(parser_state *state) { expression *lhs = clause; expression *rhs = parse_term(state); if (!rhs) { + free_expression(lhs); return NULL; } - clause = new_expression_binary(lhs, rhs, eval_or); + clause = new_or_expression(lhs, rhs); } return clause; @@ -622,6 +698,17 @@ static bool eval_comma(const expression *expr, eval_state *state) { } /** + * Create a "comma" expression. + */ +static expression *new_comma_expression(expression *lhs, expression *rhs) { + if (lhs == &expr_true || lhs == &expr_false) { + return rhs; + } else { + return new_binary_expression(lhs, rhs, eval_comma); + } +} + +/** * EXPR : CLAUSE * | EXPR "," CLAUSE */ @@ -643,10 +730,11 @@ static expression *parse_expression(parser_state *state) { expression *lhs = expr; expression *rhs = parse_clause(state); if (!rhs) { + free_expression(lhs); return NULL; } - expr = new_expression_binary(lhs, rhs, eval_comma); + expr = new_comma_expression(lhs, rhs); } return expr; @@ -668,7 +756,7 @@ static cmdline *parse_cmdline(int argc, char *argv[]) { cl->mindepth = 0; cl->maxdepth = INT_MAX; cl->flags = BFTW_RECOVER; - cl->expr = NULL; + cl->expr = &expr_true; parser_state state = { .cl = cl, @@ -695,16 +783,9 @@ static cmdline *parse_cmdline(int argc, char *argv[]) { goto fail; } - if (cl->expr) { - expression *expr = new_expression_binary(cl->expr, print, eval_and); - if (!expr) { - free_expression(print); - goto fail; - } - - cl->expr = expr; - } else { - cl->expr = print; + cl->expr = new_and_expression(cl->expr, print); + if (!cl->expr) { + goto fail; } } |