opt: Separate optimization from parsing

1 files changed, 225 insertions, 0 deletions

diff --git a/expr.h b/expr.h
new file mode 100644
index 0000000..0eba0da
--- /dev/null
+++ b/expr.h
@@ -0,0 +1,225 @@
+/****************************************************************************
+ * bfs                                                                      *
+ * Copyright (C) 2015-2017 Tavian Barnes <tavianator@tavianator.com>        *
+ *                                                                          *
+ * Permission to use, copy, modify, and/or distribute this software for any *
+ * purpose with or without fee is hereby granted.                           *
+ *                                                                          *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF         *
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR  *
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES   *
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN    *
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF  *
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.           *
+ ****************************************************************************/
+
+#ifndef EXPR_H
+#define EXPR_H
+
+#include "color.h"
+#include "exec.h"
+#include "printf.h"
+#include <regex.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <sys/types.h>
+#include <time.h>
+
+/**
+ * A command line expression.
+ */
+struct expr;
+
+/**
+ * Ephemeral state for evaluating an expression.
+ */
+struct eval_state;
+
+/**
+ * Expression evaluation function.
+ *
+ * @param expr
+ *         The current expression.
+ * @param state
+ *         The current evaluation state.
+ * @return
+ *         The result of the test.
+ */
+typedef bool eval_fn(const struct expr *expr, struct eval_state *state);
+
+/**
+ * Possible types of numeric comparison.
+ */
+enum cmp_flag {
+	/** Exactly n. */
+	CMP_EXACT,
+	/** Less than n. */
+	CMP_LESS,
+	/** Greater than n. */
+	CMP_GREATER,
+};
+
+/**
+ * Possible types of mode comparison.
+ */
+enum mode_cmp {
+	/** Mode is an exact match (MODE). */
+	MODE_EXACT,
+	/** Mode has all these bits (-MODE). */
+	MODE_ALL,
+	/** Mode has any of these bits (/MODE). */
+	MODE_ANY,
+};
+
+/**
+ * Available struct stat time fields.
+ */
+enum time_field {
+	/** Access time. */
+	ATIME,
+	/** Status change time. */
+	CTIME,
+	/** Modification time. */
+	MTIME,
+};
+
+/**
+ * Possible time units.
+ */
+enum time_unit {
+	/** Minutes. */
+	MINUTES,
+	/** Days. */
+	DAYS,
+};
+
+/**
+ * Possible file size units.
+ */
+enum size_unit {
+	/** 512-byte blocks. */
+	SIZE_BLOCKS,
+	/** Single bytes. */
+	SIZE_BYTES,
+	/** Two-byte words. */
+	SIZE_WORDS,
+	/** Kibibytes. */
+	SIZE_KB,
+	/** Mebibytes. */
+	SIZE_MB,
+	/** Gibibytes. */
+	SIZE_GB,
+	/** Tebibytes. */
+	SIZE_TB,
+	/** Pebibytes. */
+	SIZE_PB,
+};
+
+struct expr {
+	/** The function that evaluates this expression. */
+	eval_fn *eval;
+
+	/** The left hand side of the expression. */
+	struct expr *lhs;
+	/** The right hand side of the expression. */
+	struct expr *rhs;
+
+	/** Whether this expression has no side effects. */
+	bool pure;
+	/** Whether this expression always evaluates to true. */
+	bool always_true;
+	/** Whether this expression always evaluates to false. */
+	bool always_false;
+
+	/** Estimated cost. */
+	double cost;
+	/** Estimated probability of success. */
+	double probability;
+	/** Number of times this predicate was executed. */
+	size_t evaluations;
+	/** Number of times this predicate succeeded. */
+	size_t successes;
+	/** Total time spent running this predicate. */
+	struct timespec elapsed;
+
+	/** The number of command line arguments for this expression. */
+	size_t argc;
+	/** The command line arguments comprising this expression. */
+	char **argv;
+
+	/** The optional comparison flag. */
+	enum cmp_flag cmp_flag;
+
+	/** The mode comparison flag. */
+	enum mode_cmp mode_cmp;
+	/** Mode to use for files. */
+	mode_t file_mode;
+	/** Mode to use for directories (different due to X). */
+	mode_t dir_mode;
+
+	/** The optional reference time. */
+	struct timespec reftime;
+	/** The optional time field. */
+	enum time_field time_field;
+	/** The optional time unit. */
+	enum time_unit time_unit;
+
+	/** The optional size unit. */
+	enum size_unit size_unit;
+
+	/** Optional device number for a target file. */
+	dev_t dev;
+	/** Optional inode number for a target file. */
+	ino_t ino;
+
+	/** File to output to. */
+	CFILE *cfile;
+
+	/** Optional compiled regex. */
+	regex_t *regex;
+
+	/** Optional exec command. */
+	struct bfs_exec *execbuf;
+
+	/** Optional printf command. */
+	struct bfs_printf *printf;
+
+	/** Optional integer data for this expression. */
+	long long idata;
+
+	/** Optional string data for this expression. */
+	const char *sdata;
+};
+
+/** Singleton true expression instance. */
+extern struct expr expr_true;
+/** Singleton false expression instance. */
+extern struct expr expr_false;
+
+/**
+ * Create a new expression.
+ */
+struct expr *new_expr(eval_fn *eval, size_t argc, char **argv);
+
+/**
+ * @return Whether expr is known to always quit.
+ */
+bool expr_never_returns(const struct expr *expr);
+
+/**
+ * @return The result of the comparison for this expression.
+ */
+bool expr_cmp(const struct expr *expr, long long n);
+
+/**
+ * Dump a parsed expression.
+ */
+void dump_expr(CFILE *cfile, const struct expr *expr, bool verbose);
+
+/**
+ * Free an expression tree.
+ */
+void free_expr(struct expr *expr);
+
+#endif // EXPR_H