path: root/bp.c

//
// bp.c - Source code for the bp parser
//
// See `man ./bp.1` for more details
//
#include <fcntl.h>
#include <glob.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "compiler.h"
#include "file_loader.h"
#include "grammar.h"
#include "json.h"
#include "printing.h"
#include "utils.h"
#include "vm.h"

static const char *usage = (
    "BP - a Parsing Expression Grammar command line tool\n\n"
    "Usage:\n"
    "  bp [flags] <pattern> [<input files>...]\n\n"
    "Flags:\n"
    " -h --help                        print the usage and quit\n"
    " -v --verbose                     print verbose debugging info\n"
    " -e --explain                     explain the matches\n"
    " -j --json                        print matches as a list of JSON objects\n"
    " -I --inplace                     modify a file in-place\n"
    " -i --ignore-case                 preform matching case-insensitively\n"
    " -l --list-files                  list filenames only\n"
    " -d --define <name>:<def>         define a grammar rule\n"
    " -D --define-string <name>:<def>  define a grammar rule (string-pattern)\n"
    " -p --pattern <pat>               provide a pattern (equivalent to bp '\\(<pat>)')\n"
    " -P --pattern-string <pat>        provide a string pattern (may be useful if '<pat>' begins with a '-')\n"
    " -r --replace <replacement>       replace the input pattern with the given replacement\n"
    " -m --mode <mode>                 set the behavior mode (defult: find-all)\n"
    " -g --grammar <grammar file>      use the specified file as a grammar\n");

static print_options_t print_options = 0;

__attribute__((nonnull))
static char *getflag(const char *flag, char *argv[], int *i);
__attribute__((nonnull(3)))
static int process_file(def_t *defs, const char *filename, vm_op_t *pattern, unsigned int flags);

//
// Return a pointer to the value part of a flag, if present, otherwise NULL.
// This works for --foo=value or --foo value
//
static char *getflag(const char *flag, char *argv[], int *i)
{
    size_t n = strlen(flag);
    check(argv[*i], "Attempt to get flag from NULL argument");
    if (strncmp(argv[*i], flag, n) == 0) {
        if (argv[*i][n] == '=') {
            return &argv[*i][n+1];
        } else if (argv[*i][n] == '\0') {
            check(argv[*i+1], "Expected argument after '%s'\n\n%s", flag, usage);
            ++(*i);
            return argv[*i];
        }
    }
    return NULL;
}

//
// For a given filename, open the file and attempt to match the given pattern
// against it, printing any results according to the flags.
//
static int process_file(def_t *defs, const char *filename, vm_op_t *pattern, unsigned int flags)
{
    static int printed_matches = 0;
    int success = 0;
    file_t *f = load_file(NULL, filename);
    check(f, "Could not open file: %s", filename);
    if (flags & BP_INPLACE) // Need to do this before matching
        intern_file(f);
    match_t *m = match(defs, f, f->contents, pattern, flags);
    if (m && print_errors(f, m, print_options) > 0)
        exit(1);

    if (m != NULL && m->end > m->start + 1) {
        success = 1;
        ++printed_matches;

        if (flags & BP_EXPLAIN) {
            if (filename)
                printf("\033[1;4m%s\033[0m\n", filename);
            visualize_match(m);
        } else if (flags & BP_LISTFILES) {
            printf("%s\n", filename);
        } else if (flags & BP_JSON) {
            if (printed_matches > 1)
                printf(",\n");
            printf("{\"filename\":\"%s\",", filename ? filename : "-");
            printf("\"tree\":{\"rule\":\"text\",\"start\":%d,\"end\":%ld,\"children\":[",
                   0, f->end - f->contents);
            json_match(f->contents, m, (flags & BP_VERBOSE) ? 1 : 0);
            printf("]}}\n");
        } else if (flags & BP_INPLACE && filename) {
            FILE *out = fopen(filename, "w");
            print_match(out, f, m, 0);
            fclose(out);
            printf("%s\n", filename);
        } else {
            if (printed_matches > 1)
                fputc('\n', stdout);
            if (filename) {
                if (print_options & PRINT_COLOR)
                    printf("\033[1;4;33m%s\033[0m\n", filename);
                else
                    printf("%s:\n", filename);
            }
            print_match(stdout, f, m,
                filename ? print_options : print_options & (print_options_t)~PRINT_LINE_NUMBERS);
        }
    }

    recycle_if_unused(&m);
    check(recycle_all_matches() == 0, "Memory leak: there should no longer be any matches in use at this point.");
    destroy_file(&f);

    return success;
}

#define FLAG(f) (flag=getflag((f), argv, &i))

int main(int argc, char *argv[])
{
    unsigned int flags = 0;
    char *flag = NULL;
    char path[PATH_MAX] = {0};
    const char *mode = "find-all";

    def_t *defs = NULL;

    file_t *loaded_files = NULL;

    // Define an opcode that is just a reference to the rule `pattern`
    file_t *pat_file = spoof_file(&loaded_files, "<pattern>", "pattern");
    vm_op_t *pattern = bp_pattern(pat_file, pat_file->contents);

    // Load builtins:
    if (access("/etc/xdg/bp/builtins.bp", R_OK) != -1) {
        file_t *f = load_file(&loaded_files, "/etc/xdg/bp/builtins.bp");
        defs = load_grammar(defs, f);
    }
    sprintf(path, "%s/.config/bp/builtins.bp", getenv("HOME"));
    if (access(path, R_OK) != -1) {
        file_t *f = load_file(&loaded_files, path);
        defs = load_grammar(defs, f);
    }

    int i, npatterns = 0;
    check(argc > 1, "%s", usage);
    for (i = 1; i < argc; i++) {
        if (streq(argv[i], "--")) {
            ++i;
            break;
        } else if (streq(argv[i], "--help")) {
          flag_help:
            printf("%s\n", usage);
            return 0;
        } else if (streq(argv[i], "--verbose")) {
            flags |= BP_VERBOSE;
        } else if (streq(argv[i], "--explain")) {
            flags |= BP_EXPLAIN;
        } else if (streq(argv[i], "--json")) {
            flags |= BP_JSON;
        } else if (streq(argv[i], "--inplace")) {
            flags |= BP_INPLACE;
        } else if (streq(argv[i], "--ignore-case")) {
            flags |= BP_IGNORECASE;
        } else if (streq(argv[i], "--list-files")) {
            flags |= BP_LISTFILES;
        } else if (FLAG("--replace") || FLAG("-r")) {
            // TODO: spoof file as sprintf("pattern => '%s'", flag)
            // except that would require handling edge cases like quotation marks etc.
            file_t *replace_file = spoof_file(&loaded_files, "<replace argument>", flag);
            vm_op_t *rep = bp_replacement(replace_file, pattern, replace_file->contents);
            check(rep, "Replacement failed to compile: %s", flag);
            defs = with_def(defs, replace_file, strlen("replacement"), "replacement", rep);
            mode = "replace-all";
        } else if (FLAG("--grammar") || FLAG("-g")) {
            file_t *f = load_file(&loaded_files, flag);
            if (f == NULL) {
                sprintf(path, "%s/.config/bp/%s.bp", getenv("HOME"), flag);
                f = load_file(&loaded_files, path);
            }
            if (f == NULL) {
                sprintf(path, "/etc/xdg/bp/%s.bp", flag);
                f = load_file(&loaded_files, path);
            }
            check(f != NULL, "Couldn't find grammar: %s", flag);
            defs = load_grammar(defs, f); // Keep in memory for debug output
        } else if (FLAG("--define") || FLAG("-d")) {
            char *def = flag;
            char *eq = strchr(def, ':');
            check(eq, "Rule definitions must include an ':'\n\n%s", usage);
            *eq = '\0';
            char *src = ++eq;
            file_t *def_file = spoof_file(&loaded_files, def, src);
            vm_op_t *pat = bp_pattern(def_file, def_file->contents);
            check(pat, "Failed to compile pattern: %s", flag);
            defs = with_def(defs, def_file, strlen(def), def, pat);
        } else if (FLAG("--define-string") || FLAG("-D")) {
            char *def = flag;
            char *eq = strchr(def, ':');
            check(eq, "Rule definitions must include an ':'\n\n%s", usage);
            *eq = '\0';
            char *src = ++eq;
            file_t *def_file = spoof_file(&loaded_files, def, src);
            vm_op_t *pat = bp_stringpattern(def_file, def_file->contents);
            check(pat, "Failed to compile pattern: %s", src);
            defs = with_def(defs, def_file, strlen(def), def, pat);
        } else if (FLAG("--pattern") || FLAG("-p")) {
            check(npatterns == 0, "Cannot define multiple patterns");
            file_t *arg_file = spoof_file(&loaded_files, "<pattern argument>", flag);
            vm_op_t *p = bp_pattern(arg_file, arg_file->contents);
            check(p, "Pattern failed to compile: %s", flag);
            defs = with_def(defs, arg_file, strlen("pattern"), "pattern", p);
            ++npatterns;
        } else if (FLAG("--pattern-string") || FLAG("-P")) {
            file_t *arg_file = spoof_file(&loaded_files, "<pattern argument>", flag);
            vm_op_t *p = bp_stringpattern(arg_file, arg_file->contents);
            check(p, "Pattern failed to compile: %s", flag);
            defs = with_def(defs, arg_file, strlen("pattern"), "pattern", p);
            ++npatterns;
        } else if (FLAG("--mode") || FLAG("-m")) {
            mode = flag;
        } else if (argv[i][0] == '-' && argv[i][1] && argv[i][1] != '-') { // single-char flags
            for (char *c = &argv[i][1]; *c; ++c) {
                switch (*c) {
                    case 'h': goto flag_help; // -h
                    case 'v': flags |= BP_VERBOSE; break; // -v
                    case 'e': flags |= BP_EXPLAIN; break; // -e
                    case 'j': flags |= BP_JSON; break; // -j
                    case 'I': flags |= BP_INPLACE; break; // -I
                    case 'i': flags |= BP_IGNORECASE; break; // -i
                    case 'l': flags |= BP_LISTFILES; break; // -l
                    default:
                        printf("Unrecognized flag: -%c\n\n%s\n", *c, usage);
                        return 1;
                }
            }
        } else if (argv[i][0] != '-') {
            if (npatterns > 0) break;
            // TODO: spoof file with quotation marks for better debugging
            file_t *arg_file = spoof_file(&loaded_files, "<pattern argument>", argv[i]);
            vm_op_t *p = bp_stringpattern(arg_file, arg_file->contents);
            check(p, "Pattern failed to compile: %s", argv[i]);
            defs = with_def(defs, arg_file, strlen("pattern"), "pattern", p);
            ++npatterns;
        } else {
            printf("Unrecognized flag: %s\n\n%s\n", argv[i], usage);
            return 1;
        }
    }

    if (((flags & BP_JSON) != 0) + ((flags & BP_EXPLAIN) != 0) + ((flags & BP_LISTFILES) != 0) > 1) {
        printf("Please choose no more than one of the flags: -j/--json, -e/--explain, and -l/--list-files.\n"
               "They are mutually contradictory.\n");
        return 1;
    }

    if (isatty(STDOUT_FILENO)) {
        print_options |= PRINT_COLOR | PRINT_LINE_NUMBERS;
    }

    // Define an opcode that is just a reference to the overarching mode (e.g. find-all)
    if (lookup(defs, mode) == NULL) {
        printf("The mode '%s' is not defined.\n", mode);
        return 1;
    }
    file_t *mode_file = spoof_file(&loaded_files, "<mode>", mode);
    vm_op_t *mode_op = bp_pattern(mode_file, mode_file->contents);

    int found = 0;
    if (flags & BP_JSON) printf("[");
    if (i < argc) {
        // Files pass in as command line args:
        for (int nfiles = 0; i < argc; nfiles++, i++) {
            found += process_file(defs, argv[i], mode_op, flags);
        }
    } else if (isatty(STDIN_FILENO)) {
        // No files, no piped in input, so use * **/*:
        glob_t globbuf;
        glob("*", 0, NULL, &globbuf);
        glob("**/*", GLOB_APPEND, NULL, &globbuf);
        for (size_t i = 0; i < globbuf.gl_pathc; i++) {
            found += process_file(defs, globbuf.gl_pathv[i], mode_op, flags);
        }
        globfree(&globbuf);
    } else {
        // Piped in input:
        found += process_file(defs, NULL, mode_op, flags);
    }
    if (flags & BP_JSON) printf("]\n");

#ifdef FREE_ON_EXIT
    // This code frees up all residual heap-allocated memory. Since the program
    // is about to exit, this step is unnecessary. However, it is useful for
    // tracking down memory leaks.
    free_defs(&defs, NULL);
    while (loaded_files) {
        file_t *next = loaded_files->next;
        destroy_file(&loaded_files);
        loaded_files = next;
    }
    free_all_matches();
#endif

    return (found > 0) ? 0 : 1;
}

// vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1