Separate filesystem utilities

1 files changed, 405 insertions, 0 deletions

diff --git a/src/filesystem.c b/src/filesystem.c
new file mode 100644
index 0000000..dbb528f
--- /dev/null
+++ b/src/filesystem.c
@@ -0,0 +1,405 @@
+/*
+  Copyright 2007-2020 David Robillard <http://drobilla.net>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS 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.
+*/
+
+#define _POSIX_C_SOURCE 200809L  /* for fileno */
+#define _BSD_SOURCE     1        /* for realpath, symlink */
+#define _DEFAULT_SOURCE 1        /* for realpath, symlink */
+
+#ifdef __APPLE__
+#    define _DARWIN_C_SOURCE 1  /* for flock */
+#endif
+
+#include "filesystem.h"
+#include "lilv_config.h"
+#include "lilv_internal.h"
+
+#ifdef _WIN32
+#    include <windows.h>
+#    include <direct.h>
+#    include <io.h>
+#    define F_OK 0
+#    define mkdir(path, flags) _mkdir(path)
+#else
+#    include <dirent.h>
+#    include <unistd.h>
+#endif
+
+#if defined(HAVE_FLOCK) && defined(HAVE_FILENO)
+#    include <sys/file.h>
+#endif
+
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifndef PAGE_SIZE
+#    define PAGE_SIZE 4096
+#endif
+
+static bool
+lilv_is_dir_sep(const char c)
+{
+	return c == '/' || c == LILV_DIR_SEP[0];
+}
+
+#ifdef _WIN32
+static inline bool
+is_windows_path(const char* path)
+{
+	return (isalpha(path[0]) && (path[1] == ':' || path[1] == '|') &&
+	        (path[2] == '/' || path[2] == '\\'));
+}
+#endif
+
+bool
+lilv_path_is_absolute(const char* path)
+{
+	if (lilv_is_dir_sep(path[0])) {
+		return true;
+	}
+
+#ifdef _WIN32
+	if (is_windows_path(path)) {
+		return true;
+	}
+#endif
+
+	return false;
+}
+
+bool
+lilv_path_is_child(const char* path, const char* dir)
+{
+	if (path && dir) {
+		const size_t path_len = strlen(path);
+		const size_t dir_len  = strlen(dir);
+		return dir && path_len >= dir_len && !strncmp(path, dir, dir_len);
+	}
+	return false;
+}
+
+char*
+lilv_path_absolute(const char* path)
+{
+	if (lilv_path_is_absolute(path)) {
+		return lilv_strdup(path);
+	} else {
+		char* cwd      = getcwd(NULL, 0);
+		char* abs_path = lilv_path_join(cwd, path);
+		free(cwd);
+		return abs_path;
+	}
+}
+
+char*
+lilv_path_relative_to(const char* path, const char* base)
+{
+	const size_t path_len = strlen(path);
+	const size_t base_len = strlen(base);
+	const size_t min_len  = (path_len < base_len) ? path_len : base_len;
+
+	// Find the last separator common to both paths
+	size_t last_shared_sep = 0;
+	for (size_t i = 0; i < min_len && path[i] == base[i]; ++i) {
+		if (lilv_is_dir_sep(path[i])) {
+			last_shared_sep = i;
+		}
+	}
+
+	if (last_shared_sep == 0) {
+		// No common components, return path
+		return lilv_strdup(path);
+	}
+
+	// Find the number of up references ("..") required
+	size_t up = 0;
+	for (size_t i = last_shared_sep + 1; i < base_len; ++i) {
+		if (lilv_is_dir_sep(base[i])) {
+			++up;
+		}
+	}
+
+	// Write up references
+	const size_t suffix_len = path_len - last_shared_sep;
+	char*        rel        = (char*)calloc(1, suffix_len + (up * 3) + 1);
+	for (size_t i = 0; i < up; ++i) {
+		memcpy(rel + (i * 3), "../", 3);
+	}
+
+	// Write suffix
+	memcpy(rel + (up * 3), path + last_shared_sep + 1, suffix_len);
+	return rel;
+}
+
+char*
+lilv_dirname(const char* path)
+{
+	const char* s = path + strlen(path) - 1;  // Last character
+	for (; s > path && lilv_is_dir_sep(*s); --s) {}  // Last non-slash
+	for (; s > path && !lilv_is_dir_sep(*s); --s) {}  // Last internal slash
+	for (; s > path && lilv_is_dir_sep(*s); --s) {}  // Skip duplicates
+
+	if (s == path) {  // Hit beginning
+		return lilv_is_dir_sep(*s) ? lilv_strdup("/") : lilv_strdup(".");
+	} else {  // Pointing to the last character of the result (inclusive)
+		char* dirname = (char*)malloc(s - path + 2);
+		memcpy(dirname, path, s - path + 1);
+		dirname[s - path + 1] = '\0';
+		return dirname;
+	}
+}
+
+char*
+lilv_path_join(const char* a, const char* b)
+{
+	if (!a) {
+		return lilv_strdup(b);
+	}
+
+	const size_t a_len   = strlen(a);
+	const size_t b_len   = b ? strlen(b) : 0;
+	const size_t pre_len = a_len - (lilv_is_dir_sep(a[a_len - 1]) ? 1 : 0);
+	char*        path    = (char*)calloc(1, a_len + b_len + 2);
+	memcpy(path, a, pre_len);
+	path[pre_len] = '/';
+	if (b) {
+		memcpy(path + pre_len + 1,
+		       b + (lilv_is_dir_sep(b[0]) ? 1 : 0),
+		       lilv_is_dir_sep(b[0]) ? b_len - 1 : b_len);
+	}
+	return path;
+}
+
+char*
+lilv_dir_path(const char* path)
+{
+	if (!path) {
+		return NULL;
+	}
+
+	const size_t len = strlen(path);
+
+	if (lilv_is_dir_sep(path[len - 1])) {
+		return lilv_strdup(path);
+	}
+
+	char* dir_path = (char*)calloc(len + 2, 1);
+	memcpy(dir_path, path, len);
+	dir_path[len] = LILV_DIR_SEP[0];
+	return dir_path;
+}
+
+char*
+lilv_realpath(const char* path)
+{
+	if (!path) {
+		return NULL;
+	}
+
+#if defined(_WIN32)
+	char* out = (char*)malloc(MAX_PATH);
+	GetFullPathName(path, MAX_PATH, out, NULL);
+	return out;
+#else
+	char* real_path = realpath(path, NULL);
+	return real_path ? real_path : lilv_strdup(path);
+#endif
+}
+
+bool
+lilv_path_exists(const char* path)
+{
+#ifdef HAVE_LSTAT
+	struct stat st;
+	return !lstat(path, &st);
+#else
+	return !access(path, F_OK);
+#endif
+}
+
+int
+lilv_copy_file(const char* src, const char* dst)
+{
+	FILE* in = fopen(src, "r");
+	if (!in) {
+		return errno;
+	}
+
+	FILE* out = fopen(dst, "w");
+	if (!out) {
+		fclose(in);
+		return errno;
+	}
+
+	char*  page   = (char*)malloc(PAGE_SIZE);
+	size_t n_read = 0;
+	int    st     = 0;
+	while ((n_read = fread(page, 1, PAGE_SIZE, in)) > 0) {
+		if (fwrite(page, 1, n_read, out) != n_read) {
+			st = errno;
+			break;
+		}
+	}
+
+	if (!st && (ferror(in) || ferror(out))) {
+		st = EBADF;
+	}
+
+	free(page);
+	fclose(in);
+	fclose(out);
+
+	return st;
+}
+
+int
+lilv_symlink(const char* oldpath, const char* newpath)
+{
+	int ret = 0;
+	if (strcmp(oldpath, newpath)) {
+#ifdef _WIN32
+#ifdef HAVE_CREATESYMBOLICLINK
+		ret = !CreateSymbolicLink(newpath, oldpath, 0);
+#endif
+		if (ret) {
+			ret = !CreateHardLink(newpath, oldpath, 0);
+		}
+#else
+		ret = symlink(oldpath, newpath);
+#endif
+	}
+	return ret;
+}
+
+int
+lilv_flock(FILE* file, bool lock)
+{
+#if defined(HAVE_FLOCK) && defined(HAVE_FILENO)
+	return flock(fileno(file), lock ? LOCK_EX : LOCK_UN);
+#else
+	return 0;
+#endif
+}
+
+void
+lilv_dir_for_each(const char* path,
+                  void*       data,
+                  void (*f)(const char* path, const char* name, void* data))
+{
+#ifdef _WIN32
+	char*           pat = lilv_path_join(path, "*");
+	WIN32_FIND_DATA fd;
+	HANDLE          fh  = FindFirstFile(pat, &fd);
+	if (fh != INVALID_HANDLE_VALUE) {
+		do {
+			f(path, fd.cFileName, data);
+		} while (FindNextFile(fh, &fd));
+	}
+	free(pat);
+#else
+	DIR* dir = opendir(path);
+	if (dir) {
+		for (struct dirent* entry = NULL; (entry = readdir(dir));) {
+			f(path, entry->d_name, data);
+		}
+		closedir(dir);
+	}
+#endif
+}
+
+int
+lilv_mkdir_p(const char* dir_path)
+{
+	char*        path     = lilv_strdup(dir_path);
+	const size_t path_len = strlen(path);
+	size_t       i        = 1;
+
+#ifdef _WIN32
+	if (is_windows_path(dir_path)) {
+		i = 3;
+	}
+#endif
+
+	for (; i <= path_len; ++i) {
+		const char c = path[i];
+		if (c == LILV_DIR_SEP[0] || c == '/' || c == '\0') {
+			path[i] = '\0';
+			if (mkdir(path, 0755) && errno != EEXIST) {
+				free(path);
+				return errno;
+			}
+			path[i] = c;
+		}
+	}
+
+	free(path);
+	return 0;
+}
+
+static off_t
+lilv_file_size(const char* path)
+{
+	struct stat buf;
+	if (stat(path, &buf)) {
+		return 0;
+	}
+	return buf.st_size;
+}
+
+bool
+lilv_file_equals(const char* a_path, const char* b_path)
+{
+	if (!strcmp(a_path, b_path)) {
+		return true;  // Paths match
+	}
+
+	bool        match  = false;
+	FILE*       a_file = NULL;
+	FILE*       b_file = NULL;
+	char* const a_real = lilv_realpath(a_path);
+	char* const b_real = lilv_realpath(b_path);
+	if (!strcmp(a_real, b_real)) {
+		match = true;  // Real paths match
+	} else if (lilv_file_size(a_path) != lilv_file_size(b_path)) {
+		match = false;  // Sizes differ
+	} else if (!(a_file = fopen(a_real, "rb")) ||
+	           !(b_file = fopen(b_real, "rb"))) {
+		match = false;  // Missing file matches nothing
+	} else {
+		// TODO: Improve performance by reading chunks
+		match = true;
+		while (!feof(a_file) && !feof(b_file)) {
+			if (fgetc(a_file) != fgetc(b_file)) {
+				match = false;
+				break;
+			}
+		}
+	}
+
+	if (a_file) {
+		fclose(a_file);
+	}
+	if (b_file) {
+		fclose(b_file);
+	}
+	free(a_real);
+	free(b_real);
+	return match;
+}