Kernel: Start using StringView in the VFS class.

The less kmalloc() we can do, the better. Calling kmalloc() disables all
interrupts while it runs, so it's directly affecting responsiveness.

3 files changed, 53 insertions, 52 deletions

diff --git a/Kernel/FileSystem/VirtualFileSystem.cpp b/Kernel/FileSystem/VirtualFileSystem.cpp
index 811b6071b9..76d25c1eb2 100644
--- a/Kernel/FileSystem/VirtualFileSystem.cpp
+++ b/Kernel/FileSystem/VirtualFileSystem.cpp
@@ -35,7 +35,7 @@ InodeIdentifier VFS::root_inode_id() const
     return m_root_inode->identifier();
 }
 
-bool VFS::mount(RetainPtr<FS>&& file_system, const String& path)
+bool VFS::mount(RetainPtr<FS>&& file_system, StringView path)
 {
     ASSERT(file_system);
     int error;
@@ -127,7 +127,7 @@ KResultOr<Retained<FileDescriptor>> VFS::open(RetainPtr<Device>&& device, int op
     return FileDescriptor::create(move(device));
 }
 
-KResult VFS::utime(const String& path, Inode& base, time_t atime, time_t mtime)
+KResult VFS::utime(StringView path, Inode& base, time_t atime, time_t mtime)
 {
     auto descriptor_or_error = VFS::the().open(move(path), 0, 0, base);
     if (descriptor_or_error.is_error())
@@ -147,7 +147,7 @@ KResult VFS::utime(const String& path, Inode& base, time_t atime, time_t mtime)
     return KSuccess;
 }
 
-KResult VFS::stat(const String& path, int options, Inode& base, struct stat& statbuf)
+KResult VFS::stat(StringView path, int options, Inode& base, struct stat& statbuf)
 {
     auto inode_or_error = resolve_path_to_inode(path, base, nullptr, options);
     if (inode_or_error.is_error())
@@ -155,7 +155,7 @@ KResult VFS::stat(const String& path, int options, Inode& base, struct stat& sta
     return FileDescriptor::create(inode_or_error.value().ptr())->fstat(statbuf);
 }
 
-KResultOr<Retained<FileDescriptor>> VFS::open(const String& path, int options, mode_t mode, Inode& base)
+KResultOr<Retained<FileDescriptor>> VFS::open(StringView path, int options, mode_t mode, Inode& base)
 {
     auto inode_or_error = resolve_path_to_inode(path, base, nullptr, options);
     if (options & O_CREAT) {
@@ -202,7 +202,7 @@ KResultOr<Retained<FileDescriptor>> VFS::open(const String& path, int options, m
     return FileDescriptor::create(*inode);
 }
 
-KResultOr<Retained<FileDescriptor>> VFS::create(const String& path, int options, mode_t mode, Inode& base)
+KResultOr<Retained<FileDescriptor>> VFS::create(StringView path, int options, mode_t mode, Inode& base)
 {
     (void)options;
 
@@ -232,7 +232,7 @@ KResultOr<Retained<FileDescriptor>> VFS::create(const String& path, int options,
     return FileDescriptor::create(move(new_file));
 }
 
-KResult VFS::mkdir(const String& path, mode_t mode, Inode& base)
+KResult VFS::mkdir(StringView path, mode_t mode, Inode& base)
 {
     RetainPtr<Inode> parent_inode;
     auto result = resolve_path_to_inode(path, base, &parent_inode);
@@ -255,7 +255,7 @@ KResult VFS::mkdir(const String& path, mode_t mode, Inode& base)
     return KResult(error);
 }
 
-KResult VFS::access(const String& path, int mode, Inode& base)
+KResult VFS::access(StringView path, int mode, Inode& base)
 {
     auto inode_or_error = resolve_path_to_inode(path, base);
     if (inode_or_error.is_error())
@@ -277,7 +277,7 @@ KResult VFS::access(const String& path, int mode, Inode& base)
     return KSuccess;
 }
 
-KResultOr<Retained<Inode>> VFS::open_directory(const String& path, Inode& base)
+KResultOr<Retained<Inode>> VFS::open_directory(StringView path, Inode& base)
 {
     auto inode_or_error = resolve_path_to_inode(path, base);
     if (inode_or_error.is_error())
@@ -303,7 +303,7 @@ KResult VFS::chmod(Inode& inode, mode_t mode)
     return inode.chmod(mode);
 }
 
-KResult VFS::chmod(const String& path, mode_t mode, Inode& base)
+KResult VFS::chmod(StringView path, mode_t mode, Inode& base)
 {
     auto inode_or_error = resolve_path_to_inode(path, base);
     if (inode_or_error.is_error())
@@ -312,7 +312,7 @@ KResult VFS::chmod(const String& path, mode_t mode, Inode& base)
     return chmod(*inode, mode);
 }
 
-KResult VFS::rename(const String& old_path, const String& new_path, Inode& base)
+KResult VFS::rename(StringView old_path, StringView new_path, Inode& base)
 {
     RetainPtr<Inode> old_parent_inode;
     auto old_inode_or_error = resolve_path_to_inode(old_path, base, &old_parent_inode);
@@ -356,7 +356,7 @@ KResult VFS::rename(const String& old_path, const String& new_path, Inode& base)
     return KSuccess;
 }
 
-KResult VFS::chown(const String& path, uid_t a_uid, gid_t a_gid, Inode& base)
+KResult VFS::chown(StringView path, uid_t a_uid, gid_t a_gid, Inode& base)
 {
     auto inode_or_error = resolve_path_to_inode(path, base);
     if (inode_or_error.is_error())
@@ -387,7 +387,7 @@ KResult VFS::chown(const String& path, uid_t a_uid, gid_t a_gid, Inode& base)
     return inode->chown(new_uid, new_gid);
 }
 
-KResultOr<Retained<Inode>> VFS::resolve_path_to_inode(const String& path, Inode& base, RetainPtr<Inode>* parent_inode, int options)
+KResultOr<Retained<Inode>> VFS::resolve_path_to_inode(StringView path, Inode& base, RetainPtr<Inode>* parent_inode, int options)
 {
     // FIXME: This won't work nicely across mount boundaries.
     FileSystemPath p(path);
@@ -402,7 +402,7 @@ KResultOr<Retained<Inode>> VFS::resolve_path_to_inode(const String& path, Inode&
     return Retained<Inode>(*get_inode(result.value()));
 }
 
-KResult VFS::link(const String& old_path, const String& new_path, Inode& base)
+KResult VFS::link(StringView old_path, StringView new_path, Inode& base)
 {
     auto old_inode_or_error = resolve_path_to_inode(old_path, base);
     if (old_inode_or_error.is_error())
@@ -429,7 +429,7 @@ KResult VFS::link(const String& old_path, const String& new_path, Inode& base)
     return parent_inode->add_child(old_inode->identifier(), FileSystemPath(new_path).basename(), 0);
 }
 
-KResult VFS::unlink(const String& path, Inode& base)
+KResult VFS::unlink(StringView path, Inode& base)
 {
     RetainPtr<Inode> parent_inode;
     auto inode_or_error = resolve_path_to_inode(path, base, &parent_inode);
@@ -446,7 +446,7 @@ KResult VFS::unlink(const String& path, Inode& base)
     return parent_inode->remove_child(FileSystemPath(path).basename());
 }
 
-KResult VFS::symlink(const String& target, const String& linkpath, Inode& base)
+KResult VFS::symlink(StringView target, StringView linkpath, Inode& base)
 {
     RetainPtr<Inode> parent_inode;
     auto existing_file_or_error = resolve_path_to_inode(linkpath, base, &parent_inode);
@@ -471,7 +471,7 @@ KResult VFS::symlink(const String& target, const String& linkpath, Inode& base)
     return KSuccess;
 }
 
-KResult VFS::rmdir(const String& path, Inode& base)
+KResult VFS::rmdir(StringView path, Inode& base)
 {
     RetainPtr<Inode> parent_inode;
     auto inode_or_error = resolve_path_to_inode(path, base, &parent_inode);
@@ -511,7 +511,7 @@ KResultOr<InodeIdentifier> VFS::resolve_symbolic_link(InodeIdentifier base, Inod
     auto symlink_contents = symlink_inode.read_entire();
     if (!symlink_contents)
         return KResult(-ENOENT);
-    auto linkee = String((const char*)symlink_contents.pointer(), symlink_contents.size());
+    auto linkee = StringView(symlink_contents.pointer(), symlink_contents.size());
 #ifdef VFS_DEBUG
     kprintf("linkee (%s)(%u) from %u:%u\n", linkee.characters(), linkee.length(), base.fsid(), base.index());
 #endif
@@ -572,12 +572,13 @@ KResultOr<String> VFS::absolute_path(Inode& core_inode)
     return builder.to_string();
 }
 
-KResultOr<InodeIdentifier> VFS::resolve_path(const String& path, InodeIdentifier base, int options, InodeIdentifier* parent_id)
+KResultOr<InodeIdentifier> VFS::resolve_path(StringView path, InodeIdentifier base, int options, InodeIdentifier* parent_id)
 {
     if (path.is_empty())
         return KResult(-EINVAL);
 
-    auto parts = path.split('/');
+    // FIXME: Use StringView::split() once it exists.
+    auto parts = String(path).split('/');
     InodeIdentifier crumb_id;
 
     if (path[0] == '/')
@@ -661,7 +662,7 @@ KResultOr<InodeIdentifier> VFS::resolve_path(const String& path, InodeIdentifier
     return crumb_id;
 }
 
-InodeIdentifier VFS::old_resolve_path(const String& path, InodeIdentifier base, int& error, int options, InodeIdentifier* parent_id)
+InodeIdentifier VFS::old_resolve_path(StringView path, InodeIdentifier base, int& error, int options, InodeIdentifier* parent_id)
 {
     auto result = resolve_path(path, base, options, parent_id);
     if (result.is_error()) {
diff --git a/Kernel/FileSystem/VirtualFileSystem.h b/Kernel/FileSystem/VirtualFileSystem.h
index e59390a1a7..cdc4c8d405 100644
--- a/Kernel/FileSystem/VirtualFileSystem.h
+++ b/Kernel/FileSystem/VirtualFileSystem.h
@@ -59,24 +59,24 @@ public:
     ~VFS();
 
     bool mount_root(RetainPtr<FS>&&);
-    bool mount(RetainPtr<FS>&&, const String& path);
+    bool mount(RetainPtr<FS>&&, StringView path);
 
     KResultOr<Retained<FileDescriptor>> open(RetainPtr<Device>&&, int options);
-    KResultOr<Retained<FileDescriptor>> open(const String& path, int options, mode_t mode, Inode& base);
-    KResultOr<Retained<FileDescriptor>> create(const String& path, int options, mode_t mode, Inode& base);
-    KResult mkdir(const String& path, mode_t mode, Inode& base);
-    KResult link(const String& old_path, const String& new_path, Inode& base);
-    KResult unlink(const String& path, Inode& base);
-    KResult symlink(const String& target, const String& linkpath, Inode& base);
-    KResult rmdir(const String& path, Inode& base);
-    KResult chmod(const String& path, mode_t, Inode& base);
+    KResultOr<Retained<FileDescriptor>> open(StringView path, int options, mode_t mode, Inode& base);
+    KResultOr<Retained<FileDescriptor>> create(StringView path, int options, mode_t mode, Inode& base);
+    KResult mkdir(StringView path, mode_t mode, Inode& base);
+    KResult link(StringView old_path, StringView new_path, Inode& base);
+    KResult unlink(StringView path, Inode& base);
+    KResult symlink(StringView target, StringView linkpath, Inode& base);
+    KResult rmdir(StringView path, Inode& base);
+    KResult chmod(StringView path, mode_t, Inode& base);
     KResult chmod(Inode&, mode_t);
-    KResult chown(const String& path, uid_t, gid_t, Inode& base);
-    KResult access(const String& path, int mode, Inode& base);
-    KResult stat(const String& path, int options, Inode& base, struct stat&);
-    KResult utime(const String& path, Inode& base, time_t atime, time_t mtime);
-    KResult rename(const String& oldpath, const String& newpath, Inode& base);
-    KResultOr<Retained<Inode>> open_directory(const String& path, Inode& base);
+    KResult chown(StringView path, uid_t, gid_t, Inode& base);
+    KResult access(StringView path, int mode, Inode& base);
+    KResult stat(StringView path, int options, Inode& base, struct stat&);
+    KResult utime(StringView path, Inode& base, time_t atime, time_t mtime);
+    KResult rename(StringView oldpath, StringView newpath, Inode& base);
+    KResultOr<Retained<Inode>> open_directory(StringView path, Inode& base);
 
     void register_device(Device&);
     void unregister_device(Device&);
@@ -103,9 +103,9 @@ private:
     bool is_vfs_root(InodeIdentifier) const;
 
     void traverse_directory_inode(Inode&, Function<bool(const FS::DirectoryEntry&)>);
-    InodeIdentifier old_resolve_path(const String& path, InodeIdentifier base, int& error, int options = 0, InodeIdentifier* parent_id = nullptr);
-    KResultOr<InodeIdentifier> resolve_path(const String& path, InodeIdentifier base, int options = 0, InodeIdentifier* parent_id = nullptr);
-    KResultOr<Retained<Inode>> resolve_path_to_inode(const String& path, Inode& base, RetainPtr<Inode>* parent_id = nullptr, int options = 0);
+    InodeIdentifier old_resolve_path(StringView path, InodeIdentifier base, int& error, int options = 0, InodeIdentifier* parent_id = nullptr);
+    KResultOr<InodeIdentifier> resolve_path(StringView path, InodeIdentifier base, int options = 0, InodeIdentifier* parent_id = nullptr);
+    KResultOr<Retained<Inode>> resolve_path_to_inode(StringView path, Inode& base, RetainPtr<Inode>* parent_id = nullptr, int options = 0);
     KResultOr<InodeIdentifier> resolve_symbolic_link(InodeIdentifier base, Inode& symlink_inode);
 
     Mount* find_mount_for_host(InodeIdentifier);
diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp
index f10a42624d..efadbc752d 100644
--- a/Kernel/Process.cpp
+++ b/Kernel/Process.cpp
@@ -287,7 +287,7 @@ int Process::do_exec(String path, Vector<String> arguments, Vector<String> envir
     if (parts.is_empty())
         return -ENOENT;
 
-    auto result = VFS::the().open(path, 0, 0, cwd_inode());
+    auto result = VFS::the().open(path.view(), 0, 0, cwd_inode());
     if (result.is_error())
         return result.error();
     auto descriptor = result.value();
@@ -905,14 +905,14 @@ int Process::sys$utime(const char* pathname, const utimbuf* buf)
         mtime = now.tv_sec;
         atime = now.tv_sec;
     }
-    return VFS::the().utime(String(pathname), cwd_inode(), atime, mtime);
+    return VFS::the().utime(StringView(pathname), cwd_inode(), atime, mtime);
 }
 
 int Process::sys$access(const char* pathname, int mode)
 {
     if (!validate_read_str(pathname))
         return -EFAULT;
-    return VFS::the().access(String(pathname), mode, cwd_inode());
+    return VFS::the().access(StringView(pathname), mode, cwd_inode());
 }
 
 int Process::sys$fcntl(int fd, int cmd, dword arg)
@@ -967,14 +967,14 @@ int Process::sys$lstat(const char* path, stat* statbuf)
 {
     if (!validate_write_typed(statbuf))
         return -EFAULT;
-    return VFS::the().stat(String(path), O_NOFOLLOW_NOERROR, cwd_inode(), *statbuf);
+    return VFS::the().stat(StringView(path), O_NOFOLLOW_NOERROR, cwd_inode(), *statbuf);
 }
 
 int Process::sys$stat(const char* path, stat* statbuf)
 {
     if (!validate_write_typed(statbuf))
         return -EFAULT;
-    return VFS::the().stat(String(path), O_NOFOLLOW_NOERROR, cwd_inode(), *statbuf);
+    return VFS::the().stat(StringView(path), O_NOFOLLOW_NOERROR, cwd_inode(), *statbuf);
 }
 
 int Process::sys$readlink(const char* path, char* buffer, ssize_t size)
@@ -1008,7 +1008,7 @@ int Process::sys$chdir(const char* path)
 {
     if (!validate_read_str(path))
         return -EFAULT;
-    auto directory_or_error = VFS::the().open_directory(String(path), cwd_inode());
+    auto directory_or_error = VFS::the().open_directory(StringView(path), cwd_inode());
     if (directory_or_error.is_error())
         return directory_or_error.error();
     m_cwd = *directory_or_error.value();
@@ -1648,7 +1648,7 @@ int Process::sys$mkdir(const char* pathname, mode_t mode)
         return -EINVAL;
     if (pathname_length >= 255)
         return -ENAMETOOLONG;
-    return VFS::the().mkdir(String(pathname, pathname_length), mode & ~umask(), cwd_inode());
+    return VFS::the().mkdir(StringView(pathname, pathname_length), mode & ~umask(), cwd_inode());
 }
 
 clock_t Process::sys$times(tms* times)
@@ -1816,14 +1816,14 @@ int Process::sys$link(const char* old_path, const char* new_path)
         return -EFAULT;
     if (!validate_read_str(new_path))
         return -EFAULT;
-    return VFS::the().link(String(old_path), String(new_path), cwd_inode());
+    return VFS::the().link(StringView(old_path), StringView(new_path), cwd_inode());
 }
 
 int Process::sys$unlink(const char* pathname)
 {
     if (!validate_read_str(pathname))
         return -EFAULT;
-    return VFS::the().unlink(String(pathname), cwd_inode());
+    return VFS::the().unlink(StringView(pathname), cwd_inode());
 }
 
 int Process::sys$symlink(const char* target, const char* linkpath)
@@ -1832,14 +1832,14 @@ int Process::sys$symlink(const char* target, const char* linkpath)
         return -EFAULT;
     if (!validate_read_str(linkpath))
         return -EFAULT;
-    return VFS::the().symlink(String(target), String(linkpath), cwd_inode());
+    return VFS::the().symlink(StringView(target), StringView(linkpath), cwd_inode());
 }
 
 int Process::sys$rmdir(const char* pathname)
 {
     if (!validate_read_str(pathname))
         return -EFAULT;
-    return VFS::the().rmdir(String(pathname), cwd_inode());
+    return VFS::the().rmdir(StringView(pathname), cwd_inode());
 }
 
 int Process::sys$read_tsc(dword* lsw, dword* msw)
@@ -1856,7 +1856,7 @@ int Process::sys$chmod(const char* pathname, mode_t mode)
 {
     if (!validate_read_str(pathname))
         return -EFAULT;
-    return VFS::the().chmod(String(pathname), mode, cwd_inode());
+    return VFS::the().chmod(StringView(pathname), mode, cwd_inode());
 }
 
 int Process::sys$fchmod(int fd, mode_t mode)
@@ -1871,7 +1871,7 @@ int Process::sys$chown(const char* pathname, uid_t uid, gid_t gid)
 {
     if (!validate_read_str(pathname))
         return -EFAULT;
-    return VFS::the().chown(String(pathname), uid, gid, cwd_inode());
+    return VFS::the().chown(StringView(pathname), uid, gid, cwd_inode());
 }
 
 void Process::finalize()
@@ -2452,7 +2452,7 @@ int Process::sys$rename(const char* oldpath, const char* newpath)
         return -EFAULT;
     if (!validate_read_str(newpath))
         return -EFAULT;
-    return VFS::the().rename(String(oldpath), String(newpath), cwd_inode());
+    return VFS::the().rename(StringView(oldpath), StringView(newpath), cwd_inode());
 }
 
 int Process::sys$shm_open(const char* name, int flags, mode_t mode)