Hooks: central vtable install with restore support

Move vtable patching into hooks.cpp: one call clones the table, validates every
slot, records the originals and installs the clone. Installs happen from the
setup, game and paint threads, so the bookkeeping is mutex-protected.

Client, CInput, IVModelRender, IStudioRender and ISurface all use it, and
hooks_restore_all() can now put every interface back (previously impossible).

1 files changed, 19 insertions, 25 deletions

diff --git a/src/hl2h.cpp b/src/hl2h.cpp
index 6697778..354b3e6 100644
--- a/src/hl2h.cpp
+++ b/src/hl2h.cpp
@@ -1125,20 +1125,17 @@ static bool hkdCreateMove(void *self, int seq, float frametime, bool active) {
   // DrawPrintText (slot 22) hooked as a fallback text-draw trigger.
   static int isurface_hooked = 0;
   if (!isurface_hooked && g_surface) {
-    void **svt = VTABLE(g_surface);
-    constexpr size_t VT_SIZE = 256;
-    void **newsvt = vtable_clone(g_surface, VT_SIZE);
-    if (!newsvt) {
-      isurface_hooked = 1; // don't retry every tick
-      logf("ISurface hook: vtable unavailable");
+    VtablePatch patches[] = {
+        {22, (void *)&hkdDrawPrintText,
+         reinterpret_cast<void **>(&oDrawPrintText)},
+        {114, (void *)&hkdPaintTraverseEx,
+         reinterpret_cast<void **>(&oPaintTraverseEx)},
+    };
+    isurface_hooked = 1; // one attempt only
+    if (!hooks_install_vtable(g_surface, 256, patches, 2)) {
+      logf("ISurface hook: vtable patch failed");
       return ret;
     }
-    oDrawPrintText = (DrawPrintTextFn)svt[22];
-    newsvt[22] = (void *)&hkdDrawPrintText;
-    oPaintTraverseEx = (PaintTraverseExFn)svt[114];
-    newsvt[114] = (void *)&hkdPaintTraverseEx;
-    VTABLE(g_surface) = newsvt;
-    isurface_hooked = 1;
     logf("ISurface hooked: DrawPrintText slot 22 orig=%p, PaintTraverseEx slot 114 orig=%p",
          (void *)oDrawPrintText, (void *)oPaintTraverseEx);
   }
@@ -1147,21 +1144,18 @@ static bool hkdCreateMove(void *self, int seq, float frametime, bool active) {
 }
 
 static void install_hook() {
-  void **vt = VTABLE(g_iface.client);
-  constexpr size_t SLOTS = 256;
-  void **newvt = vtable_clone(g_iface.client, SLOTS);
-  if (!newvt) {
-    logf("hook install: client vtable unavailable");
+  VtablePatch patches[] = {
+      {21, (void *)&hkdCreateMove, reinterpret_cast<void **>(&oCreateMove)},
+      {35, (void *)&hkdFrameStageNotify,
+       reinterpret_cast<void **>(&oFrameStageNotify)},
+  };
+  if (!hooks_install_vtable(g_iface.client, 256, patches, 2)) {
+    logf("hook install: client vtable patch failed");
     return;
   }
-  oCreateMove = (CreateMoveFn)vt[21];
-  newvt[21] = (void *)&hkdCreateMove;
-  oFrameStageNotify = (FrameStageFn)vt[35];
-  newvt[35] = (void *)&hkdFrameStageNotify;
-  VTABLE(g_iface.client) = newvt;
-  logf("hook installed: CreateMove %p -> %p (orig %p), FrameStageNotify %p "
-       "-> %p (orig %p)",
-       vt[21], (void *)&hkdCreateMove, (void *)oCreateMove, vt[35],
+  logf("hook installed: CreateMove -> %p (orig %p), FrameStageNotify -> %p "
+       "(orig %p)",
+       (void *)&hkdCreateMove, (void *)oCreateMove,
        (void *)&hkdFrameStageNotify, (void *)oFrameStageNotify);
 }