Split out parsing code.

1 files changed, 263 insertions, 0 deletions

diff --git a/eval.c b/eval.c
new file mode 100644
index 0000000..56238ea
--- /dev/null
+++ b/eval.c
@@ -0,0 +1,263 @@
+#include "bfs.h"
+#include "bftw.h"
+#include <errno.h>
+#include <fcntl.h>
+#include <fnmatch.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/resource.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+struct eval_state {
+	/** Data about the current file. */
+	struct BFTW *ftwbuf;
+	/** The parsed command line. */
+	const cmdline *cl;
+	/** The bftw() callback return value. */
+	bftw_action action;
+	/** A stat() buffer, if necessary. */
+	struct stat statbuf;
+};
+
+/**
+ * Perform a stat() call if necessary.
+ */
+static void fill_statbuf(eval_state *state) {
+	struct BFTW *ftwbuf = state->ftwbuf;
+	if (ftwbuf->statbuf) {
+		return;
+	}
+
+	if (fstatat(ftwbuf->at_fd, ftwbuf->at_path, &state->statbuf, AT_SYMLINK_NOFOLLOW) == 0) {
+		ftwbuf->statbuf = &state->statbuf;
+	} else {
+		perror("fstatat()");
+	}
+}
+
+/**
+ * -true test.
+ */
+bool eval_true(const expression *expr, eval_state *state) {
+	return true;
+}
+
+/**
+ * -false test.
+ */
+bool eval_false(const expression *expr, eval_state *state) {
+	return false;
+}
+
+/**
+ * -executable, -readable, -writable action.
+ */
+bool eval_access(const expression *expr, eval_state *state) {
+	struct BFTW *ftwbuf = state->ftwbuf;
+	return faccessat(ftwbuf->at_fd, ftwbuf->at_path, expr->idata, AT_SYMLINK_NOFOLLOW) == 0;
+}
+
+/**
+ * -delete action.
+ */
+bool eval_delete(const expression *expr, eval_state *state) {
+	struct BFTW *ftwbuf = state->ftwbuf;
+
+	int flag = 0;
+	if (ftwbuf->typeflag == BFTW_DIR) {
+		flag |= AT_REMOVEDIR;
+	}
+
+	if (unlinkat(ftwbuf->at_fd, ftwbuf->at_path, flag) != 0) {
+		print_error(state->cl->colors, ftwbuf->path, errno);
+		state->action = BFTW_STOP;
+	}
+
+	return true;
+}
+
+/**
+ * -prune action.
+ */
+bool eval_prune(const expression *expr, eval_state *state) {
+	state->action = BFTW_SKIP_SUBTREE;
+	return true;
+}
+
+/**
+ * -hidden test.
+ */
+bool eval_hidden(const expression *expr, eval_state *state) {
+	struct BFTW *ftwbuf = state->ftwbuf;
+	return ftwbuf->nameoff > 0 && ftwbuf->path[ftwbuf->nameoff] == '.';
+}
+
+/**
+ * -nohidden action.
+ */
+bool eval_nohidden(const expression *expr, eval_state *state) {
+	if (eval_hidden(expr, state)) {
+		eval_prune(expr, state);
+		return false;
+	} else {
+		return true;
+	}
+}
+
+/**
+ * -name test.
+ */
+bool eval_name(const expression *expr, eval_state *state) {
+	struct BFTW *ftwbuf = state->ftwbuf;
+	return fnmatch(expr->sdata, ftwbuf->path + ftwbuf->nameoff, 0) == 0;
+}
+
+/**
+ * -path test.
+ */
+bool eval_path(const expression *expr, eval_state *state) {
+	struct BFTW *ftwbuf = state->ftwbuf;
+	return fnmatch(expr->sdata, ftwbuf->path, 0) == 0;
+}
+
+/**
+ * -print action.
+ */
+bool eval_print(const expression *expr, eval_state *state) {
+	color_table *colors = state->cl->colors;
+	if (colors) {
+		fill_statbuf(state);
+	}
+	pretty_print(colors, state->ftwbuf);
+	return true;
+}
+
+/**
+ * -print0 action.
+ */
+bool eval_print0(const expression *expr, eval_state *state) {
+	const char *path = state->ftwbuf->path;
+	fwrite(path, 1, strlen(path) + 1, stdout);
+	return true;
+}
+
+/**
+ * -quit action.
+ */
+bool eval_quit(const expression *expr, eval_state *state) {
+	state->action = BFTW_STOP;
+	return true;
+}
+
+/**
+ * -type test.
+ */
+bool eval_type(const expression *expr, eval_state *state) {
+	return state->ftwbuf->typeflag == expr->idata;
+}
+
+/**
+ * Evaluate a negation.
+ */
+bool eval_not(const expression *expr, eval_state *state) {
+	return !expr->rhs->eval(expr, state);
+}
+
+/**
+ * Evaluate a conjunction.
+ */
+bool eval_and(const expression *expr, eval_state *state) {
+	return expr->lhs->eval(expr->lhs, state) && expr->rhs->eval(expr->rhs, state);
+}
+
+/**
+ * Evaluate a disjunction.
+ */
+bool eval_or(const expression *expr, eval_state *state) {
+	return expr->lhs->eval(expr->lhs, state) || expr->rhs->eval(expr->rhs, state);
+}
+
+/**
+ * Evaluate the comma operator.
+ */
+bool eval_comma(const expression *expr, eval_state *state) {
+	expr->lhs->eval(expr->lhs, state);
+	return expr->rhs->eval(expr->rhs, state);
+}
+
+/**
+ * Infer the number of open file descriptors we're allowed to have.
+ */
+static int infer_nopenfd() {
+	int ret = 4096;
+
+	struct rlimit rl;
+	if (getrlimit(RLIMIT_NOFILE, &rl) == 0) {
+		if (rl.rlim_cur != RLIM_INFINITY) {
+			ret = rl.rlim_cur;
+		}
+	}
+
+	// Account for std{in,out,err}
+	if (ret > 3) {
+		ret -= 3;
+	}
+
+	return ret;
+}
+
+/**
+ * bftw() callback.
+ */
+static bftw_action cmdline_callback(struct BFTW *ftwbuf, void *ptr) {
+	const cmdline *cl = ptr;
+
+	if (ftwbuf->typeflag == BFTW_ERROR) {
+		print_error(cl->colors, ftwbuf->path, ftwbuf->error);
+		return BFTW_SKIP_SUBTREE;
+	}
+
+	eval_state state = {
+		.ftwbuf = ftwbuf,
+		.cl = cl,
+		.action = BFTW_CONTINUE,
+	};
+
+	if (ftwbuf->depth >= cl->maxdepth) {
+		state.action = BFTW_SKIP_SUBTREE;
+	}
+
+	// In -depth mode, only handle directories on the BFTW_POST visit
+	bftw_visit expected_visit = BFTW_PRE;
+	if ((cl->flags & BFTW_DEPTH)
+	    && ftwbuf->typeflag == BFTW_DIR
+	    && ftwbuf->depth < cl->maxdepth) {
+		expected_visit = BFTW_POST;
+	}
+
+	if (ftwbuf->visit == expected_visit
+	    && ftwbuf->depth >= cl->mindepth
+	    && ftwbuf->depth <= cl->maxdepth) {
+		cl->expr->eval(cl->expr, &state);
+	}
+
+	return state.action;
+}
+
+/**
+ * Evaluate the command line.
+ */
+int eval_cmdline(cmdline *cl) {
+	int ret = 0;
+	int nopenfd = infer_nopenfd();
+
+	for (size_t i = 0; i < cl->nroots; ++i) {
+		if (bftw(cl->roots[i], cmdline_callback, nopenfd, cl->flags, cl) != 0) {
+			ret = -1;
+			perror("bftw()");
+		}
+	}
+
+	return ret;
+}