vulkan: refactor layer enumeration

Replace Enumerate*Layers by a set of new functions that do not distinguish
instance and device layers.  The new functions are also careful not to
pollute the rest of the loader with std containers.

There should be no user-visible change.

Bug: 27911856
Change-Id: I4790fadc1aa2ea934a4628bce55dd45892f15e0b

1 files changed, 35 insertions, 8 deletions

diff --git a/vulkan/libvulkan/api.cpp b/vulkan/libvulkan/api.cpp
index e7f10b351b..e3f69fea82 100644
--- a/vulkan/libvulkan/api.cpp
+++ b/vulkan/libvulkan/api.cpp
@@ -1098,13 +1098,19 @@ VkResult EnumerateInstanceLayerProperties(uint32_t* pPropertyCount,
     if (!EnsureInitialized())
         return VK_ERROR_INITIALIZATION_FAILED;
 
-    uint32_t count =
-        EnumerateInstanceLayers(pProperties ? *pPropertyCount : 0, pProperties);
+    uint32_t count = GetLayerCount();
 
-    if (!pProperties || *pPropertyCount > count)
+    if (!pProperties) {
         *pPropertyCount = count;
+        return VK_SUCCESS;
+    }
+
+    uint32_t copied = std::min(*pPropertyCount, count);
+    for (uint32_t i = 0; i < copied; i++)
+        pProperties[i] = GetLayerProperties(GetLayer(i));
+    *pPropertyCount = copied;
 
-    return *pPropertyCount < count ? VK_INCOMPLETE : VK_SUCCESS;
+    return (copied == count) ? VK_SUCCESS : VK_INCOMPLETE;
 }
 
 VkResult EnumerateInstanceExtensionProperties(
@@ -1137,13 +1143,34 @@ VkResult EnumerateDeviceLayerProperties(VkPhysicalDevice physicalDevice,
                                         VkLayerProperties* pProperties) {
     (void)physicalDevice;
 
-    uint32_t count =
-        EnumerateDeviceLayers(pProperties ? *pPropertyCount : 0, pProperties);
+    uint32_t total_count = GetLayerCount();
+
+    if (!pProperties) {
+        uint32_t count = 0;
+        for (uint32_t i = 0; i < total_count; i++) {
+            if (IsLayerGlobal(GetLayer(i)))
+                count++;
+        }
 
-    if (!pProperties || *pPropertyCount > count)
         *pPropertyCount = count;
+        return VK_SUCCESS;
+    }
+
+    uint32_t count = 0;
+    uint32_t copied = 0;
+    for (uint32_t i = 0; i < total_count; i++) {
+        const Layer& layer = GetLayer(i);
+        if (!IsLayerGlobal(layer))
+            continue;
+
+        count++;
+        if (copied < *pPropertyCount)
+            pProperties[copied++] = GetLayerProperties(layer);
+    }
+
+    *pPropertyCount = copied;
 
-    return *pPropertyCount < count ? VK_INCOMPLETE : VK_SUCCESS;
+    return (copied == count) ? VK_SUCCESS : VK_INCOMPLETE;
 }
 
 VkResult EnumerateDeviceExtensionProperties(