path: root/src/stdlib/paths.c

// A lang for filesystem paths

#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <ftw.h>
#include <gc.h>
#include <glob.h>
#include <grp.h>
#include <pwd.h>
#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include "../unistr-fixed.h"
#include "../util.h"
#include "enums.h"
#include "integers.h"
#include "lists.h"
#include "optionals.h"
#include "paths.h"
#include "print.h"
#include "structs.h"
#include "text.h"
#include "types.h"
#include "util.h"

static const Path_t HOME_PATH = Path$tagged$HomePath(EMPTY_LIST), ROOT_PATH = Path$tagged$AbsolutePath(EMPTY_LIST),
                    CURDIR_PATH = Path$tagged$RelativePath(EMPTY_LIST);

static void clean_components(List_t *components) {
    for (int64_t i = 0; i < (int64_t)components->length;) {
        Text_t *component = (Text_t *)(components->data + i * components->stride);
        if (component->length == 0 || Text$equal_values(*component, Text("."))) {
            List$remove_at(components, I(i + 1), I(1), sizeof(Text_t));
        } else if (i > 0 && Text$equal_values(*component, Text(".."))) {
            Text_t *prev = (Text_t *)(components->data + (i - 1) * components->stride);
            if (!Text$equal_values(*prev, Text(".."))) {
                List$remove_at(components, I(i), I(2), sizeof(Text_t));
                i -= 1;
            } else {
                i += 1;
            }
        } else {
            i += 1;
        }
    }
}

public
Path_t Path$from_str(const char *str) {
    if (!str || str[0] == '\0' || streq(str, "/")) return ROOT_PATH;
    else if (streq(str, "~")) return HOME_PATH;
    else if (streq(str, ".")) return CURDIR_PATH;

    if (strchr(str, ';') != NULL) fail("Path has illegal character (semicolon): ", str);

    Path_t result = {};
    if (str[0] == '/') {
        result.$tag = Path$tag$AbsolutePath;
        str += 1;
    } else if (str[0] == '~' && str[1] == '/') {
        result.$tag = Path$tag$HomePath;
        str += 2;
    } else if (str[0] == '.' && str[1] == '/') {
        result.$tag = Path$tag$RelativePath;
        str += 2;
    } else {
        result.$tag = Path$tag$RelativePath;
    }

    List_t components = EMPTY_LIST;
    while (str && *str) {
        size_t component_len = strcspn(str, "/");
        if (component_len > 0) {
            if (component_len == 1 && str[0] == '.') {
                // ignore /./
            } else if (component_len == 2 && strncmp(str, "..", 2) == 0 && components.length > 1
                       && !Text$equal_values(
                           Text(".."),
                           *(Text_t *)(components.data + components.stride * ((int64_t)components.length - 1)))) {
                // Pop off /foo/baz/.. -> /foo
                List$remove_at(&components, I((int64_t)components.length), I(1), sizeof(Text_t));
            } else {
                Text_t component = Text$from_strn(str, component_len);
                List$insert_value(&components, component, I(0), sizeof(Text_t));
            }
            str += component_len;
        }
        str += strspn(str, "/");
    }
    result.components = components;
    return result;
}

public
Path_t Path$from_text(Text_t text) {
    return Path$from_str(Text$as_c_string(text));
}

public
Path_t Path$expand_home(Path_t path) {
    if (path.$tag == Path$tag$HomePath) {
        Path_t pwd = Path$from_str(getenv("HOME"));
        List_t components = List$concat(pwd.AbsolutePath.components, path.HomePath.components, sizeof(Text_t));
        assert(components.length == path.HomePath.components.length + pwd.AbsolutePath.components.length);
        clean_components(&components);
        path = Path$tagged$AbsolutePath(components);
    }
    return path;
}

public
Path_t Path$_concat(int n, Path_t items[n]) {
    assert(n > 0);
    Path_t result = items[0];
    LIST_INCREF(result.components);
    for (int i = 1; i < n; i++) {
        if (items[i].$tag != Path$tag$RelativePath)
            fail("Cannot concatenate an absolute or home-based path onto another path: (", items[i], ")");
        List$insert_all(&result.components, items[i].components, I(0), sizeof(Text_t));
    }
    clean_components(&result.components);
    return result;
}

public
Path_t Path$resolved(Path_t path, Path_t relative_to) {
    if (path.$tag == Path$tag$HomePath) {
        return Path$expand_home(path);
    } else if (path.$tag == Path$tag$RelativePath
               && !(relative_to.$tag == Path$tag$RelativePath && relative_to.components.length == 0)) {
        Path_t result = {
            .$tag = relative_to.$tag,
            .components = relative_to.components,
        };
        LIST_INCREF(result.components);
        List$insert_all(&result.components, path.components, I(0), sizeof(Text_t));
        clean_components(&result.components);
        return result;
    }
    return path;
}

public
Path_t Path$relative_to(Path_t path, Path_t relative_to) {
    if (path.$tag != relative_to.$tag) {
        path = Path$resolved(path, Path$current_dir());
        relative_to = Path$resolved(relative_to, Path$current_dir());
    }

    Path_t result = Path$tagged$RelativePath(EMPTY_LIST);
    int64_t shared = 0;
    while (shared < (int64_t)path.components.length && shared < (int64_t)relative_to.components.length) {
        Text_t *p = (Text_t *)(path.components.data + shared * path.components.stride);
        Text_t *r = (Text_t *)(relative_to.components.data + shared * relative_to.components.stride);
        if (!Text$equal_values(*p, *r)) break;
        shared += 1;
    }

    for (int64_t i = shared; i < (int64_t)relative_to.components.length; i++)
        List$insert_value(&result.components, Text(".."), I(1), sizeof(Text_t));

    for (int64_t i = shared; i < (int64_t)path.components.length; i++) {
        Text_t *p = (Text_t *)(path.components.data + i * path.components.stride);
        List$insert(&result.components, p, I(0), sizeof(Text_t));
    }
    return result;
}

public
bool Path$exists(Path_t path) {
    path = Path$expand_home(path);
    struct stat sb;
    return (stat(Path$as_c_string(path), &sb) == 0);
}

static INLINE int path_stat(Path_t path, bool follow_symlinks, struct stat *sb) {
    path = Path$expand_home(path);
    const char *path_str = Path$as_c_string(path);
    return follow_symlinks ? stat(path_str, sb) : lstat(path_str, sb);
}

public
bool Path$is_file(Path_t path, bool follow_symlinks) {
    struct stat sb;
    int status = path_stat(path, follow_symlinks, &sb);
    if (status != 0) return false;
    return (sb.st_mode & S_IFMT) == S_IFREG;
}

public
bool Path$is_directory(Path_t path, bool follow_symlinks) {
    struct stat sb;
    int status = path_stat(path, follow_symlinks, &sb);
    if (status != 0) return false;
    return (sb.st_mode & S_IFMT) == S_IFDIR;
}

public
bool Path$is_pipe(Path_t path, bool follow_symlinks) {
    struct stat sb;
    int status = path_stat(path, follow_symlinks, &sb);
    if (status != 0) return false;
    return (sb.st_mode & S_IFMT) == S_IFIFO;
}

public
bool Path$is_socket(Path_t path, bool follow_symlinks) {
    struct stat sb;
    int status = path_stat(path, follow_symlinks, &sb);
    if (status != 0) return false;
    return (sb.st_mode & S_IFMT) == S_IFSOCK;
}

public
bool Path$is_symlink(Path_t path) {
    struct stat sb;
    int status = path_stat(path, false, &sb);
    if (status != 0) return false;
    return (sb.st_mode & S_IFMT) == S_IFLNK;
}

public
bool Path$can_read(Path_t path) {
    path = Path$expand_home(path);
    const char *path_str = Path$as_c_string(path);
#ifdef _GNU_SOURCE
    return (euidaccess(path_str, R_OK) == 0);
#else
    return (access(path_str, R_OK) == 0);
#endif
}

public
bool Path$can_write(Path_t path) {
    path = Path$expand_home(path);
    const char *path_str = Path$as_c_string(path);
#ifdef _GNU_SOURCE
    return (euidaccess(path_str, W_OK) == 0);
#else
    return (access(path_str, W_OK) == 0);
#endif
}

public
bool Path$can_execute(Path_t path) {
    path = Path$expand_home(path);
    const char *path_str = Path$as_c_string(path);
#ifdef _GNU_SOURCE
    return (euidaccess(path_str, X_OK) == 0);
#else
    return (access(path_str, X_OK) == 0);
#endif
}

public
OptionalInt64_t Path$modified(Path_t path, bool follow_symlinks) {
    struct stat sb;
    int status = path_stat(path, follow_symlinks, &sb);
    if (status != 0) return NONE_INT64;
    return (OptionalInt64_t){.value = (int64_t)sb.st_mtime};
}

public
OptionalInt64_t Path$accessed(Path_t path, bool follow_symlinks) {
    struct stat sb;
    int status = path_stat(path, follow_symlinks, &sb);
    if (status != 0) return NONE_INT64;
    return (OptionalInt64_t){.value = (int64_t)sb.st_atime};
}

public
OptionalInt64_t Path$changed(Path_t path, bool follow_symlinks) {
    struct stat sb;
    int status = path_stat(path, follow_symlinks, &sb);
    if (status != 0) return NONE_INT64;
    return (OptionalInt64_t){.value = (int64_t)sb.st_ctime};
}

static Result_t _write(Path_t path, List_t bytes, int mode, int permissions) {
    path = Path$expand_home(path);
    const char *path_str = Path$as_c_string(path);
    int fd = open(path_str, mode, permissions);
    if (fd == -1) {
        if (errno == EMFILE || errno == ENFILE) {
            // If we hit file handle limits, run GC collection to try to clean up any lingering file handles that will
            // be closed by GC finalizers.
            GC_gcollect();
            fd = open(path_str, mode, permissions);
        }
        if (fd == -1) return FailureResult("Could not write to file: ", path_str, " (", strerror(errno), ")");
    }

    if (bytes.stride != 1) List$compact(&bytes, 1);
    ssize_t written = write(fd, bytes.data, (size_t)bytes.length);
    if (written != (ssize_t)bytes.length)
        return FailureResult("Could not write to file: ", path_str, " (", strerror(errno), ")");
    close(fd);
    return SuccessResult;
}

public
Result_t Path$write(Path_t path, Text_t text, int permissions) {
    List_t bytes = Text$utf8(text);
    return _write(path, bytes, O_WRONLY | O_CREAT | O_TRUNC, permissions);
}

public
Result_t Path$write_bytes(Path_t path, List_t bytes, int permissions) {
    return _write(path, bytes, O_WRONLY | O_CREAT | O_TRUNC, permissions);
}

public
Result_t Path$append(Path_t path, Text_t text, int permissions) {
    List_t bytes = Text$utf8(text);
    return _write(path, bytes, O_WRONLY | O_APPEND | O_CREAT, permissions);
}

public
Result_t Path$append_bytes(Path_t path, List_t bytes, int permissions) {
    return _write(path, bytes, O_WRONLY | O_APPEND | O_CREAT, permissions);
}

typedef struct {
    const char *path_str;
    int fd;
    int mode;
    int permissions;
} writer_data_t;

static Result_t _write_bytes_to_fd(List_t bytes, bool close_file, void *userdata) {
    writer_data_t *data = userdata;
    if (bytes.length > 0) {
        if (data->fd == -1) {
            data->fd = open(data->path_str, data->mode, data->permissions);
            if (data->fd == -1) {
                if (errno == EMFILE || errno == ENFILE) {
                    // If we hit file handle limits, run GC collection to try to clean up any lingering file handles
                    // that will be closed by GC finalizers.
                    GC_gcollect();
                    data->fd = open(data->path_str, data->mode, data->permissions);
                }
                if (data->fd == -1)
                    return FailureResult("Could not write to file: ", data->path_str, " (", strerror(errno), ")");
            }
        }

        if (bytes.stride != 1) List$compact(&bytes, 1);
        ssize_t written = write(data->fd, bytes.data, (size_t)bytes.length);
        if (written != (ssize_t)bytes.length)
            return FailureResult("Could not write to file: ", data->path_str, " (", strerror(errno), ")");
    }
    // After first successful write, all writes are appends
    data->mode = (O_WRONLY | O_CREAT | O_APPEND);

    if (close_file && data->fd != -1) {
        if (close(data->fd) == -1)
            return FailureResult("Failed to close file: ", data->path_str, " (", strerror(errno), ")");
        data->fd = -1;
    }
    return SuccessResult;
}

static Result_t _write_text_to_fd(Text_t text, bool close_file, void *userdata) {
    return _write_bytes_to_fd(Text$utf8(text), close_file, userdata);
}

static void _writer_cleanup(writer_data_t *data) {
    if (data && data->fd != -1) {
        close(data->fd);
        data->fd = -1;
    }
}

public
Closure_t Path$byte_writer(Path_t path, bool append, int permissions) {
    path = Path$expand_home(path);
    const char *path_str = Path$as_c_string(path);
    int mode = append ? (O_WRONLY | O_CREAT | O_APPEND) : (O_WRONLY | O_CREAT | O_TRUNC);
    writer_data_t *userdata =
        new (writer_data_t, .fd = -1, .path_str = path_str, .mode = mode, .permissions = permissions);
    GC_register_finalizer(userdata, (void *)_writer_cleanup, NULL, NULL, NULL);
    return (Closure_t){.fn = _write_bytes_to_fd, .userdata = userdata};
}

public
Closure_t Path$writer(Path_t path, bool append, int permissions) {
    path = Path$expand_home(path);
    const char *path_str = Path$as_c_string(path);
    int mode = append ? (O_WRONLY | O_CREAT | O_APPEND) : (O_WRONLY | O_CREAT | O_TRUNC);
    writer_data_t *userdata =
        new (writer_data_t, .fd = -1, .path_str = path_str, .mode = mode, .permissions = permissions);
    GC_register_finalizer(userdata, (void *)_writer_cleanup, NULL, NULL, NULL);
    return (Closure_t){.fn = _write_text_to_fd, .userdata = userdata};
}

public
OptionalList_t Path$read_bytes(Path_t path, OptionalInt_t count) {
    path = Path$expand_home(path);
    const char *path_str = Path$as_c_string(path);
    int fd = open(path_str, O_RDONLY);
    if (fd == -1) {
        if (errno == EMFILE || errno == ENFILE) {
            // If we hit file handle limits, run GC collection to try to clean up any lingering file handles that
            // will be closed by GC finalizers.
            GC_gcollect();
            fd = open(path_str, O_RDONLY);
        }
    }

    if (fd == -1) return NONE_LIST;

    struct stat sb;
    if (fstat(fd, &sb) != 0) return NONE_LIST;

    int64_t const target_count = count.small ? Int64$from_int(count, false) : INT64_MAX;
    if (target_count < 0) fail("Cannot read a negative number of bytes!");

    if ((sb.st_mode & S_IFMT) == S_IFREG) { // Use memory mapping if it's a real file:
        const char *mem = mmap(NULL, (size_t)sb.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
        char *content = GC_MALLOC_ATOMIC((size_t)sb.st_size + 1);
        memcpy(content, mem, (size_t)sb.st_size);
        content[sb.st_size] = '\0';
        close(fd);
        if (count.small && (int64_t)sb.st_size < target_count) return NONE_LIST;
        int64_t len = count.small ? target_count : (int64_t)sb.st_size;
        return (List_t){.data = content, .atomic = 1, .stride = 1, .length = (uint64_t)len};
    } else {
        size_t capacity = 256, len = 0;
        char *content = GC_MALLOC_ATOMIC(capacity);
        int64_t count_remaining = target_count;
        for (;;) {
            char chunk[256];
            size_t to_read = count_remaining < (int64_t)sizeof(chunk) ? (size_t)count_remaining : sizeof(chunk);
            ssize_t just_read = read(fd, chunk, to_read);
            if (just_read < 0) {
                close(fd);
                return NONE_LIST;
            } else if (just_read == 0) {
                if (errno == EAGAIN || errno == EINTR) continue;
                break;
            }
            count_remaining -= (int64_t)just_read;

            if (len + (size_t)just_read >= capacity) {
                content = GC_REALLOC(content, (capacity *= 2));
            }

            memcpy(&content[len], chunk, (size_t)just_read);
            len += (size_t)just_read;
        }
        close(fd);
        if (count.small != 0 && (int64_t)len < target_count) return NONE_LIST;
        return (List_t){.data = content, .atomic = 1, .stride = 1, .length = (uint64_t)len};
    }
}

public
OptionalText_t Path$read(Path_t path) {
    List_t bytes = Path$read_bytes(path, NONE_INT);
    if (bytes.data == NULL) return NONE_TEXT;
    return Text$from_utf8(bytes);
}

public
OptionalText_t Path$owner(Path_t path, bool follow_symlinks) {
    struct stat sb;
    int status = path_stat(path, follow_symlinks, &sb);
    if (status != 0) return NONE_TEXT;
    struct passwd *pw = getpwuid(sb.st_uid);
    return pw ? Text$from_str(pw->pw_name) : NONE_TEXT;
}

public
OptionalText_t Path$group(Path_t path, bool follow_symlinks) {
    struct stat sb;
    int status = path_stat(path, follow_symlinks, &sb);
    if (status != 0) return NONE_TEXT;
    struct group *gr = getgrgid(sb.st_uid);
    return gr ? Text$from_str(gr->gr_name) : NONE_TEXT;
}

public
Result_t Path$set_owner(Path_t path, OptionalText_t owner, OptionalText_t group, bool follow_symlinks) {
    uid_t owner_id = (uid_t)-1;
    if (owner.tag == TEXT_NONE) {
        struct passwd *pwd = getpwnam(Text$as_c_string(owner));
        if (pwd == NULL) return FailureResult("Not a valid user: ", owner);
        owner_id = pwd->pw_uid;
    }

    gid_t group_id = (gid_t)-1;
    if (group.tag == TEXT_NONE) {
        struct group *grp = getgrnam(Text$as_c_string(group));
        if (grp == NULL) return FailureResult("Not a valid group: ", group);
        group_id = grp->gr_gid;
    }
    const char *path_str = Path$as_c_string(path);
    int result = follow_symlinks ? chown(path_str, owner_id, group_id) : lchown(path_str, owner_id, group_id);
    if (result < 0) return FailureResult("Could not set owner!");
    return SuccessResult;
}

static int _remove_files(const char *path, const struct stat *sbuf, int type, struct FTW *ftwb) {
    (void)sbuf, (void)ftwb;
    switch (type) {
    case FTW_F:
    case FTW_SL:
    case FTW_SLN:
        if (remove(path) < 0) {
            fail("Could not remove file: ", path, " (", strerror(errno), ")");
            return -1;
        }
        return 0;
    case FTW_DP:
        if (rmdir(path) != 0) fail("Could not remove directory: ", path, " (", strerror(errno), ")");
        return 0;
    default: fail("Could not remove path: ", path, " (not a file or directory)"); return -1;
    }
}

public
Result_t Path$remove(Path_t path, bool ignore_missing) {
    path = Path$expand_home(path);
    const char *path_str = Path$as_c_string(path);
    struct stat sb;
    if (lstat(path_str, &sb) != 0) {
        if (!ignore_missing) return FailureResult("Could not remove file: ", path_str, " (", strerror(errno), ")");
        return SuccessResult;
    }

    if ((sb.st_mode & S_IFMT) == S_IFREG || (sb.st_mode & S_IFMT) == S_IFLNK) {
        if (unlink(path_str) != 0 && !ignore_missing)
            return FailureResult("Could not remove file: ", path_str, " (", strerror(errno), ")");
    } else if ((sb.st_mode & S_IFMT) == S_IFDIR) {
        const int num_open_fd = 10;
        if (nftw(path_str, _remove_files, num_open_fd, FTW_DEPTH | FTW_MOUNT | FTW_PHYS) < 0)
            return FailureResult("Could not remove directory: ", path_str, " (", strerror(errno), ")");
    } else {
        return FailureResult("Could not remove path: ", path_str, " (not a file or directory)");
    }
    return SuccessResult;
}

public
Result_t Path$create_directory(Path_t path, int permissions, bool recursive) {
retry:
    path = Path$expand_home(path);
    const char *c_path = Path$as_c_string(path);
    int status = mkdir(c_path, (mode_t)permissions);
    if (status != 0) {
        if (recursive && errno == ENOENT) {
            Path$create_directory(Path$parent(path), permissions, recursive);
            goto retry;
        } else if (errno != EEXIST) {
            return FailureResult("Could not create directory: ", c_path, " (", strerror(errno), ")");
        }
    }
    return SuccessResult;
}

static OptionalList_t _filtered_children(Path_t path, bool include_hidden, mode_t filter) {
    path = Path$expand_home(path);
    struct dirent *dir;
    List_t children = EMPTY_LIST;
    const char *path_str = Path$as_c_string(path);
    size_t path_len = strlen(path_str);
    DIR *d = opendir(path_str);
    if (!d) return NONE_LIST;

    if (path_str[path_len - 1] == '/') --path_len;

    while ((dir = readdir(d)) != NULL) {
        if (!include_hidden && dir->d_name[0] == '.') continue;
        if (streq(dir->d_name, ".") || streq(dir->d_name, "..")) continue;

        const char *child_str = String(string_slice(path_str, path_len), "/", dir->d_name);
        struct stat sb;
        if (stat(child_str, &sb) != 0) continue;
        if (!((sb.st_mode & S_IFMT) & filter)) continue;

        Path_t child = Path$from_str(child_str);
        List$insert(&children, &child, I(0), sizeof(Path_t));
    }
    closedir(d);
    return children;
}

public
OptionalList_t Path$children(Path_t path, bool include_hidden) {
    return _filtered_children(path, include_hidden, (mode_t)-1);
}

public
OptionalList_t Path$files(Path_t path, bool include_hidden) {
    return _filtered_children(path, include_hidden, S_IFREG);
}

public
OptionalList_t Path$subdirectories(Path_t path, bool include_hidden) {
    return _filtered_children(path, include_hidden, S_IFDIR);
}

public
OptionalPath_t Path$unique_directory(Path_t path) {
    path = Path$expand_home(path);
    const char *path_str = Path$as_c_string(path);
    size_t len = strlen(path_str);
    if (len >= PATH_MAX) fail("Path is too long: ", path_str);
    char buf[PATH_MAX] = {};
    memcpy(buf, path_str, len);
    buf[len] = '\0';
    if (buf[len - 1] == '/') buf[--len] = '\0';
    char *created = mkdtemp(buf);
    if (!created) return NONE_PATH;
    return Path$from_str(created);
}

public
OptionalPath_t Path$write_unique_bytes(Path_t path, List_t bytes) {
    path = Path$expand_home(path);
    const char *path_str = Path$as_c_string(path);
    size_t len = strlen(path_str);
    if (len >= PATH_MAX) fail("Path is too long: ", path_str);
    char buf[PATH_MAX] = {};
    memcpy(buf, path_str, len);
    buf[len] = '\0';

    // Count the number of trailing characters leading up to the last "X"
    // (e.g. "foo_XXXXXX.tmp" would yield suffixlen = 4)
    size_t suffixlen = 0;
    while (suffixlen < len && buf[len - 1 - suffixlen] != 'X')
        ++suffixlen;

    int fd = mkstemps(buf, suffixlen);
    if (fd == -1) return NONE_PATH;

    if (bytes.stride != 1) List$compact(&bytes, 1);

    ssize_t written = write(fd, bytes.data, (size_t)bytes.length);
    if (written != (ssize_t)bytes.length) fail("Could not write to file: ", buf, " (", strerror(errno), ")");
    close(fd);
    return Path$from_str(buf);
}

public
OptionalPath_t Path$write_unique(Path_t path, Text_t text) {
    return Path$write_unique_bytes(path, Text$utf8(text));
}

public
OptionalPath_t Path$parent(Path_t path) {
    if (path.$tag == Path$tag$AbsolutePath && path.components.length == 0) {
        return NONE_PATH;
    } else if (path.components.length > 0
               && !Text$equal_values(
                   *(Text_t *)(path.components.data + path.components.stride * ((int64_t)path.components.length - 1)),
                   Text(".."))) {
        return (Path_t){.$tag = path.$tag, .components = List$slice(path.components, I(1), I(-2))};
    } else {
        Path_t result = {.$tag = path.$tag, .components = path.components};
        LIST_INCREF(result.components);
        List$insert_value(&result.components, Text(".."), I(0), sizeof(Text_t));
        return result;
    }
}

public
PUREFUNC Text_t Path$base_name(Path_t path) {
    if (path.components.length >= 1)
        return *(Text_t *)(path.components.data + path.components.stride * ((int64_t)path.components.length - 1));
    else if (path.$tag == Path$tag$HomePath) return Text("~");
    else if (path.$tag == Path$tag$RelativePath) return Text(".");
    else return EMPTY_TEXT;
}

public
Text_t Path$extension(Path_t path, bool full) {
    const char *base = Text$as_c_string(Path$base_name(path));
    const char *dot = full ? strchr(base + 1, '.') : strrchr(base + 1, '.');
    const char *extension = dot ? dot + 1 : "";
    return Text$from_str(extension);
}

public
bool Path$has_extension(Path_t path, Text_t extension) {
    if (path.components.length < 2) return extension.length == 0;

    Text_t last = *(Text_t *)(path.components.data + path.components.stride * ((int64_t)path.components.length - 1));

    if (extension.length == 0)
        return !Text$has(Text$from(last, I(2)), Text(".")) || Text$equal_values(last, Text(".."));

    if (!Text$starts_with(extension, Text("."), NULL)) extension = Text$concat(Text("."), extension);

    return Text$ends_with(Text$from(last, I(2)), extension, NULL);
}

public
Path_t Path$child(Path_t path, Text_t name) {
    if (Text$has(name, Text("/")) || Text$has(name, Text(";"))) fail("Path name has invalid characters: ", name);
    Path_t result = {
        .$tag = path.$tag,
        .components = path.components,
    };
    LIST_INCREF(result.components);
    List$insert(&result.components, &name, I(0), sizeof(Text_t));
    clean_components(&result.components);
    return result;
}

public
Path_t Path$sibling(Path_t path, Text_t name) {
    return Path$child(Path$parent(path), name);
}

public
OptionalPath_t Path$with_extension(Path_t path, Text_t extension, bool replace) {
    if (path.components.length == 0) return NONE_PATH;

    if (Text$has(extension, Text("/")) || Text$has(extension, Text(";"))) return NONE_PATH;

    Path_t result = {
        .$tag = path.$tag,
        .components = path.components,
    };
    LIST_INCREF(result.components);
    Text_t last = *(Text_t *)(path.components.data + path.components.stride * ((int64_t)path.components.length - 1));
    List$remove_at(&result.components, I(-1), I(1), sizeof(Text_t));
    if (replace) {
        const char *base = Text$as_c_string(last);
        const char *dot = strchr(base + 1, '.');
        if (dot) last = Text$from_strn(base, (size_t)(dot - base));
    }

    last = Text$concat(last, extension);
    List$insert(&result.components, &last, I(0), sizeof(Text_t));
    return result;
}

static void _line_reader_cleanup(FILE **f) {
    if (f && *f) {
        fclose(*f);
        *f = NULL;
    }
}

static Text_t _next_line(FILE **f) {
    if (!f || !*f) return NONE_TEXT;

    char *line = NULL;
    size_t size = 0;
next_line:;
    ssize_t len = getline(&line, &size, *f);
    if (len <= 0) {
        if (line != NULL) free(line);
        _line_reader_cleanup(f);
        return NONE_TEXT;
    }

    while (len > 0 && (line[len - 1] == '\r' || line[len - 1] == '\n'))
        --len;

    if (u8_check((uint8_t *)line, (size_t)len) != NULL) {
        // If there's invalid UTF8, skip this line and move to the next
        goto next_line;
    }

    Text_t line_text = Text$from_strn(line, (size_t)len);
    free(line);
    return line_text;
}

public
OptionalClosure_t Path$by_line(Path_t path) {
    path = Path$expand_home(path);

    const char *path_str = Path$as_c_string(path);
    FILE *f = fopen(path_str, "r");
    if (f == NULL) {
        if (errno == EMFILE || errno == ENFILE) {
            // If we hit file handle limits, run GC collection to try to clean up any lingering file handles that
            // will be closed by GC finalizers.
            GC_gcollect();
            f = fopen(path_str, "r");
        }
    }

    if (f == NULL) return NONE_CLOSURE;

    FILE **wrapper = GC_MALLOC(sizeof(FILE *));
    *wrapper = f;
    GC_register_finalizer(wrapper, (void *)_line_reader_cleanup, NULL, NULL, NULL);
    return (Closure_t){.fn = (void *)_next_line, .userdata = wrapper};
}

public
OptionalList_t Path$lines(Path_t path) {
    const char *path_str = Path$as_c_string(path);
    FILE *f = fopen(path_str, "r");
    if (f == NULL) {
        if (errno == EMFILE || errno == ENFILE) {
            // If we hit file handle limits, run GC collection to try to clean up any lingering file handles that
            // will be closed by GC finalizers.
            GC_gcollect();
            f = fopen(path_str, "r");
        }
    }

    if (f == NULL) return NONE_LIST;

    List_t lines = EMPTY_LIST;
    for (OptionalText_t line; (line = _next_line(&f)).tag != TEXT_NONE;) {
        List$insert(&lines, &line, I(0), sizeof(line));
    }
    return lines;
}

public
List_t Path$glob(Path_t path) {
    glob_t glob_result;
    int status = glob(Path$as_c_string(path), GLOB_BRACE | GLOB_TILDE, NULL, &glob_result);
    if (status != 0 && status != GLOB_NOMATCH) fail("Failed to perform globbing");

    List_t glob_files = EMPTY_LIST;
    for (size_t i = 0; i < glob_result.gl_pathc; i++) {
        size_t len = strlen(glob_result.gl_pathv[i]);
        if ((len >= 2 && glob_result.gl_pathv[i][len - 1] == '.' && glob_result.gl_pathv[i][len - 2] == '/')
            || (len >= 2 && glob_result.gl_pathv[i][len - 1] == '.' && glob_result.gl_pathv[i][len - 2] == '.'
                && glob_result.gl_pathv[i][len - 3] == '/'))
            continue;
        Path_t p = Path$from_str(glob_result.gl_pathv[i]);
        List$insert(&glob_files, &p, I(0), sizeof(Path_t));
    }
    return glob_files;
}

public
Path_t Path$current_dir(void) {
    char cwd[PATH_MAX];
    if (getcwd(cwd, sizeof(cwd)) == NULL) fail("Could not get current working directory");
    return Path$from_str(cwd);
}

public
int Path$print(FILE *f, Path_t path) {
    if (path.components.length == 0) {
        if (path.$tag == Path$tag$AbsolutePath) return fputs("/", f);
        else if (path.$tag == Path$tag$RelativePath) return fputs(".", f);
        else if (path.$tag == Path$tag$HomePath) return fputs("~", f);
    }

    int n = 0;
    if (path.$tag == Path$tag$AbsolutePath) {
        n += fputc('/', f);
    } else if (path.$tag == Path$tag$HomePath) {
        n += fputs("~/", f);
    } else if (path.$tag == Path$tag$RelativePath) {
        if (!Text$equal_values(*(Text_t *)path.components.data, Text(".."))) n += fputs("./", f);
    }

    for (int64_t i = 0; i < (int64_t)path.components.length; i++) {
        Text_t *comp = (Text_t *)(path.components.data + i * path.components.stride);
        n += Text$print(f, *comp);
        if (i + 1 < (int64_t)path.components.length) n += fputc('/', f);
    }
    return n;
}

public
const char *Path$as_c_string(Path_t path) {
    return String(path);
}

public
Text_t Path$as_text(const void *obj, bool color, const TypeInfo_t *type) {
    (void)type;
    if (!obj) return Text("Path");
    Path_t *path = (Path_t *)obj;
    Text_t text = Text$join(Text("/"), path->components);
    if (path->$tag == Path$tag$HomePath) text = Text$concat(path->components.length > 0 ? Text("~/") : Text("~"), text);
    else if (path->$tag == Path$tag$AbsolutePath) text = Text$concat(Text("/"), text);
    else if (path->$tag == Path$tag$RelativePath
             && (path->components.length == 0 || !Text$equal_values(*(Text_t *)(path->components.data), Text(".."))))
        text = Text$concat(path->components.length > 0 ? Text("./") : Text("."), text);

    if (color) text = Text$concat(Text("\033[32;1m"), text, Text("\033[m"));

    return text;
}

public
const TypeInfo_t Path$AbsolutePath$$info = {
    .size = sizeof(Path$AbsolutePath$$type),
    .align = __alignof__(Path$AbsolutePath$$type),
    .metamethods = Struct$metamethods,
    .tag = StructInfo,
    .StructInfo =
        {
            .name = "AbsolutePath",
            .num_fields = 1,
            .fields = (NamedType_t[1]){{
                .name = "components",
                .type = List$info(&Text$info),
            }},
        },
};

public
const TypeInfo_t Path$RelativePath$$info = {
    .size = sizeof(Path$RelativePath$$type),
    .align = __alignof__(Path$RelativePath$$type),
    .metamethods = Struct$metamethods,
    .tag = StructInfo,
    .StructInfo =
        {
            .name = "RelativePath",
            .num_fields = 1,
            .fields = (NamedType_t[1]){{
                .name = "components",
                .type = List$info(&Text$info),
            }},
        },
};

public
const TypeInfo_t Path$HomePath$$info = {
    .size = sizeof(Path$HomePath$$type),
    .align = __alignof__(Path$HomePath$$type),
    .metamethods = Struct$metamethods,
    .tag = StructInfo,
    .StructInfo =
        {
            .name = "HomePath",
            .num_fields = 1,
            .fields = (NamedType_t[1]){{
                .name = "components",
                .type = List$info(&Text$info),
            }},
        },
};

public
const TypeInfo_t Path$info = {
    .size = sizeof(Path_t),
    .align = __alignof__(Path_t),
    .tag = EnumInfo,
    .EnumInfo =
        {
            .name = "Path",
            .num_tags = 3,
            .tags =
                (NamedType_t[3]){
                    {.name = "AbsolutePath", &Path$AbsolutePath$$info},
                    {.name = "RelativePath", &Path$RelativePath$$info},
                    {.name = "HomePath", &Path$HomePath$$info},
                },
        },
    .metamethods =
        {
            .as_text = Path$as_text,
            .compare = Enum$compare,
            .equal = Enum$equal,
            .hash = Enum$hash,
            .is_none = Enum$is_none,
            .serialize = Enum$serialize,
            .deserialize = Enum$deserialize,
        },
};