Commit 6943cefebf

Andrew Kelley <superjoe30@gmail.com>
2018-06-14 22:15:32
std.os.path.dirname: return null instead of empty slice
for when there is no directory component. Makes it harder to write bugs. closes #1017
1 parent 2219cc0
Changed files (5)
src-self-hosted/introspect.zig
@@ -27,7 +27,7 @@ pub fn findZigLibDir(allocator: *mem.Allocator) ![]u8 {
 
     var cur_path: []const u8 = self_exe_path;
     while (true) {
-        const test_dir = os.path.dirname(cur_path);
+        const test_dir = os.path.dirname(cur_path) orelse ".";
 
         if (mem.eql(u8, test_dir, cur_path)) {
             break;
src-self-hosted/main.zig
@@ -249,7 +249,7 @@ fn cmdBuild(allocator: *Allocator, args: []const []const u8) !void {
     defer build_args.deinit();
 
     const build_file_basename = os.path.basename(build_file_abs);
-    const build_file_dirname = os.path.dirname(build_file_abs);
+    const build_file_dirname = os.path.dirname(build_file_abs) orelse ".";
 
     var full_cache_dir: []u8 = undefined;
     if (flags.single("cache-dir")) |cache_dir| {
std/os/index.zig
@@ -714,7 +714,7 @@ pub fn atomicSymLink(allocator: *Allocator, existing_path: []const u8, new_path:
         else => return err, // TODO zig should know this set does not include PathAlreadyExists
     }
 
-    const dirname = os.path.dirname(new_path);
+    const dirname = os.path.dirname(new_path) orelse ".";
 
     var rand_buf: [12]u8 = undefined;
     const tmp_path = try allocator.alloc(u8, dirname.len + 1 + base64.Base64Encoder.calcSize(rand_buf.len));
@@ -860,14 +860,14 @@ pub const AtomicFile = struct {
 
         var rand_buf: [12]u8 = undefined;
 
-        const dirname_component_len = if (dirname.len == 0) 0 else dirname.len + 1;
+        const dirname_component_len = if (dirname) |d| d.len + 1 else 0;
         const tmp_path = try allocator.alloc(u8, dirname_component_len +
             base64.Base64Encoder.calcSize(rand_buf.len));
         errdefer allocator.free(tmp_path);
 
-        if (dirname.len != 0) {
-            mem.copy(u8, tmp_path[0..], dirname);
-            tmp_path[dirname.len] = os.path.sep;
+        if (dirname) |dir| {
+            mem.copy(u8, tmp_path[0..], dir);
+            tmp_path[dir.len] = os.path.sep;
         }
 
         while (true) {
@@ -1965,7 +1965,7 @@ pub fn selfExeDirPath(allocator: *mem.Allocator) ![]u8 {
             // the executable was in when it was run.
             const full_exe_path = try readLink(allocator, "/proc/self/exe");
             errdefer allocator.free(full_exe_path);
-            const dir = path.dirname(full_exe_path);
+            const dir = path.dirname(full_exe_path) orelse ".";
             return allocator.shrink(u8, full_exe_path, dir.len);
         },
         Os.windows, Os.macosx, Os.ios => {
std/os/path.zig
@@ -648,8 +648,8 @@ fn testResolvePosix(paths: []const []const u8) []u8 {
 }
 
 /// If the path is a file in the current directory (no directory component)
-/// then the returned slice has .len = 0.
-pub fn dirname(path: []const u8) []const u8 {
+/// then returns null
+pub fn dirname(path: []const u8) ?[]const u8 {
     if (is_windows) {
         return dirnameWindows(path);
     } else {
@@ -657,9 +657,9 @@ pub fn dirname(path: []const u8) []const u8 {
     }
 }
 
-pub fn dirnameWindows(path: []const u8) []const u8 {
+pub fn dirnameWindows(path: []const u8) ?[]const u8 {
     if (path.len == 0)
-        return path[0..0];
+        return null;
 
     const root_slice = diskDesignatorWindows(path);
     if (path.len == root_slice.len)
@@ -671,13 +671,13 @@ pub fn dirnameWindows(path: []const u8) []const u8 {
 
     while ((path[end_index] == '/' or path[end_index] == '\\') and end_index > root_slice.len) {
         if (end_index == 0)
-            return path[0..0];
+            return null;
         end_index -= 1;
     }
 
     while (path[end_index] != '/' and path[end_index] != '\\' and end_index > root_slice.len) {
         if (end_index == 0)
-            return path[0..0];
+            return null;
         end_index -= 1;
     }
 
@@ -685,12 +685,15 @@ pub fn dirnameWindows(path: []const u8) []const u8 {
         end_index += 1;
     }
 
+    if (end_index == 0)
+        return null;
+
     return path[0..end_index];
 }
 
-pub fn dirnamePosix(path: []const u8) []const u8 {
+pub fn dirnamePosix(path: []const u8) ?[]const u8 {
     if (path.len == 0)
-        return path[0..0];
+        return null;
 
     var end_index: usize = path.len - 1;
     while (path[end_index] == '/') {
@@ -701,13 +704,16 @@ pub fn dirnamePosix(path: []const u8) []const u8 {
 
     while (path[end_index] != '/') {
         if (end_index == 0)
-            return path[0..0];
+            return null;
         end_index -= 1;
     }
 
     if (end_index == 0 and path[end_index] == '/')
         return path[0..1];
 
+    if (end_index == 0)
+        return null;
+
     return path[0..end_index];
 }
 
@@ -717,10 +723,10 @@ test "os.path.dirnamePosix" {
     testDirnamePosix("/a", "/");
     testDirnamePosix("/", "/");
     testDirnamePosix("////", "/");
-    testDirnamePosix("", "");
-    testDirnamePosix("a", "");
-    testDirnamePosix("a/", "");
-    testDirnamePosix("a//", "");
+    testDirnamePosix("", null);
+    testDirnamePosix("a", null);
+    testDirnamePosix("a/", null);
+    testDirnamePosix("a//", null);
 }
 
 test "os.path.dirnameWindows" {
@@ -742,7 +748,7 @@ test "os.path.dirnameWindows" {
     testDirnameWindows("c:foo\\bar", "c:foo");
     testDirnameWindows("c:foo\\bar\\", "c:foo");
     testDirnameWindows("c:foo\\bar\\baz", "c:foo\\bar");
-    testDirnameWindows("file:stream", "");
+    testDirnameWindows("file:stream", null);
     testDirnameWindows("dir\\file:stream", "dir");
     testDirnameWindows("\\\\unc\\share", "\\\\unc\\share");
     testDirnameWindows("\\\\unc\\share\\foo", "\\\\unc\\share\\");
@@ -753,18 +759,26 @@ test "os.path.dirnameWindows" {
     testDirnameWindows("/a/b/", "/a");
     testDirnameWindows("/a/b", "/a");
     testDirnameWindows("/a", "/");
-    testDirnameWindows("", "");
+    testDirnameWindows("", null);
     testDirnameWindows("/", "/");
     testDirnameWindows("////", "/");
-    testDirnameWindows("foo", "");
+    testDirnameWindows("foo", null);
 }
 
-fn testDirnamePosix(input: []const u8, expected_output: []const u8) void {
-    assert(mem.eql(u8, dirnamePosix(input), expected_output));
+fn testDirnamePosix(input: []const u8, expected_output: ?[]const u8) void {
+    if (dirnamePosix(input)) |output| {
+        assert(mem.eql(u8, output, expected_output.?));
+    } else {
+        assert(expected_output == null);
+    }
 }
 
-fn testDirnameWindows(input: []const u8, expected_output: []const u8) void {
-    assert(mem.eql(u8, dirnameWindows(input), expected_output));
+fn testDirnameWindows(input: []const u8, expected_output: ?[]const u8) void {
+    if (dirnameWindows(input)) |output| {
+        assert(mem.eql(u8, output, expected_output.?));
+    } else {
+        assert(expected_output == null);
+    }
 }
 
 pub fn basename(path: []const u8) []const u8 {
std/build.zig
@@ -617,7 +617,7 @@ pub const Builder = struct {
             warn("cp {} {}\n", source_path, dest_path);
         }
 
-        const dirname = os.path.dirname(dest_path);
+        const dirname = os.path.dirname(dest_path) orelse ".";
         const abs_source_path = self.pathFromRoot(source_path);
         os.makePath(self.allocator, dirname) catch |err| {
             warn("Unable to create path {}: {}\n", dirname, @errorName(err));
@@ -1395,8 +1395,9 @@ pub const LibExeObjStep = struct {
                     cc_args.append(abs_source_file) catch unreachable;
 
                     const cache_o_src = os.path.join(builder.allocator, builder.cache_root, source_file) catch unreachable;
-                    const cache_o_dir = os.path.dirname(cache_o_src);
-                    try builder.makePath(cache_o_dir);
+                    if (os.path.dirname(cache_o_src)) |cache_o_dir| {
+                        try builder.makePath(cache_o_dir);
+                    }
                     const cache_o_file = builder.fmt("{}{}", cache_o_src, self.target.oFileExt());
                     cc_args.append("-o") catch unreachable;
                     cc_args.append(builder.pathFromRoot(cache_o_file)) catch unreachable;
@@ -1509,8 +1510,9 @@ pub const LibExeObjStep = struct {
                     cc_args.append(abs_source_file) catch unreachable;
 
                     const cache_o_src = os.path.join(builder.allocator, builder.cache_root, source_file) catch unreachable;
-                    const cache_o_dir = os.path.dirname(cache_o_src);
-                    try builder.makePath(cache_o_dir);
+                    if (os.path.dirname(cache_o_src)) |cache_o_dir| {
+                        try builder.makePath(cache_o_dir);
+                    }
                     const cache_o_file = builder.fmt("{}{}", cache_o_src, self.target.oFileExt());
                     cc_args.append("-o") catch unreachable;
                     cc_args.append(builder.pathFromRoot(cache_o_file)) catch unreachable;
@@ -1855,7 +1857,7 @@ pub const WriteFileStep = struct {
     fn make(step: *Step) !void {
         const self = @fieldParentPtr(WriteFileStep, "step", step);
         const full_path = self.builder.pathFromRoot(self.file_path);
-        const full_path_dir = os.path.dirname(full_path);
+        const full_path_dir = os.path.dirname(full_path) orelse ".";
         os.makePath(self.builder.allocator, full_path_dir) catch |err| {
             warn("unable to make path {}: {}\n", full_path_dir, @errorName(err));
             return err;
@@ -1945,7 +1947,7 @@ pub const Step = struct {
 };
 
 fn doAtomicSymLinks(allocator: *Allocator, output_path: []const u8, filename_major_only: []const u8, filename_name_only: []const u8) !void {
-    const out_dir = os.path.dirname(output_path);
+    const out_dir = os.path.dirname(output_path) orelse ".";
     const out_basename = os.path.basename(output_path);
     // sym link for libfoo.so.1 to libfoo.so.1.2.3
     const major_only_path = os.path.join(allocator, out_dir, filename_major_only) catch unreachable;