Kernel: Convert SlavePTY all-instances HashTable to an IntrusiveList

This simplifies the DevPtsFS implementation somewhat, as it no longer
requires SlavePTY to register itself with it, since it can now simply
use the list of SlavePTY instances.

2 files changed, 22 insertions, 30 deletions

diff --git a/Kernel/FileSystem/DevPtsFS.cpp b/Kernel/FileSystem/DevPtsFS.cpp
index 7c84db9f0b..136a39afa2 100644
--- a/Kernel/FileSystem/DevPtsFS.cpp
+++ b/Kernel/FileSystem/DevPtsFS.cpp
@@ -1,11 +1,10 @@
 /*
  * Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
+ * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
-#include <AK/Singleton.h>
-#include <AK/StringView.h>
 #include <Kernel/FileSystem/DevPtsFS.h>
 #include <Kernel/FileSystem/VirtualFileSystem.h>
 #include <Kernel/TTY/SlavePTY.h>
@@ -25,8 +24,6 @@ DevPtsFS::~DevPtsFS()
 {
 }
 
-static Singleton<HashTable<unsigned>> s_ptys;
-
 KResult DevPtsFS::initialize()
 {
     m_root_inode = adopt_ref_if_nonnull(new (nothrow) DevPtsFSInode(*this, 1, nullptr));
@@ -80,16 +77,6 @@ RefPtr<Inode> DevPtsFS::get_inode(InodeIdentifier inode_id) const
     return inode;
 }
 
-void DevPtsFS::register_slave_pty(SlavePTY& slave_pty)
-{
-    s_ptys->set(slave_pty.index());
-}
-
-void DevPtsFS::unregister_slave_pty(SlavePTY& slave_pty)
-{
-    s_ptys->remove(slave_pty.index());
-}
-
 DevPtsFSInode::DevPtsFSInode(DevPtsFS& fs, InodeIndex index, SlavePTY* pty)
     : Inode(fs, index)
 {
@@ -129,11 +116,13 @@ KResult DevPtsFSInode::traverse_as_directory(Function<bool(FileSystem::Directory
     callback({ ".", identifier(), 0 });
     callback({ "..", identifier(), 0 });
 
-    for (unsigned pty_index : *s_ptys) {
-        String name = String::number(pty_index);
-        InodeIdentifier identifier = { fsid(), pty_index_to_inode_index(pty_index) };
-        callback({ name, identifier, 0 });
-    }
+    SlavePTY::all_instances().with([&](auto& list) {
+        for (SlavePTY& slave_pty : list) {
+            String name = String::number(slave_pty.index());
+            InodeIdentifier identifier = { fsid(), pty_index_to_inode_index(slave_pty.index()) };
+            callback({ name, identifier, 0 });
+        }
+    });
 
     return KSuccess;
 }
@@ -146,14 +135,20 @@ KResultOr<NonnullRefPtr<Inode>> DevPtsFSInode::lookup(StringView name)
         return *this;
 
     auto pty_index = name.to_uint();
-    if (pty_index.has_value() && s_ptys->contains(pty_index.value())) {
-        auto inode = fs().get_inode({ fsid(), pty_index_to_inode_index(pty_index.value()) });
-        if (!inode)
-            return ENOENT;
-        return inode.release_nonnull();
-    }
-
-    return ENOENT;
+    if (!pty_index.has_value())
+        return ENOENT;
+
+    return SlavePTY::all_instances().with([&](auto& list) -> KResultOr<NonnullRefPtr<Inode>> {
+        for (SlavePTY& slave_pty : list) {
+            if (slave_pty.index() != pty_index.value())
+                continue;
+            auto inode = fs().get_inode({ fsid(), pty_index_to_inode_index(pty_index.value()) });
+            if (!inode)
+                return ENOENT;
+            return inode.release_nonnull();
+        }
+        return ENOENT;
+    });
 }
 
 void DevPtsFSInode::flush_metadata()
diff --git a/Kernel/FileSystem/DevPtsFS.h b/Kernel/FileSystem/DevPtsFS.h
index 568b2c2ca4..d89ab1dfe4 100644
--- a/Kernel/FileSystem/DevPtsFS.h
+++ b/Kernel/FileSystem/DevPtsFS.h
@@ -27,9 +27,6 @@ public:
 
     virtual Inode& root_inode() override;
 
-    static void register_slave_pty(SlavePTY&);
-    static void unregister_slave_pty(SlavePTY&);
-
 private:
     DevPtsFS();
     RefPtr<Inode> get_inode(InodeIdentifier) const;