Merge changes I2bfa04cc,I156f1032 into main

* changes:
  vr: avoid missing std::char_traits<const T>
  ui: use std::span instead of std::basic_string_view<uint8_t>

Author: rprichard

libs/ui/DisplayIdentification.cpp

@@ -21,6 +21,7 @@
 #include <cctype>
 #include <numeric>
 #include <optional>
+#include <span>
 
 #include <log/log.h>
 
@@ -81,15 +82,16 @@ uint64_t hash64Len0To16(const char* s, uint64_t len) {
     return k2;
 }
 
-using byte_view = std::basic_string_view<uint8_t>;
+using byte_view = std::span<const uint8_t>;
 
 constexpr size_t kEdidBlockSize = 128;
 constexpr size_t kEdidHeaderLength = 5;
 
 constexpr uint16_t kVirtualEdidManufacturerId = 0xffffu;
 
 std::optional<uint8_t> getEdidDescriptorType(const byte_view& view) {
-    if (view.size() < kEdidHeaderLength || view[0] || view[1] || view[2] || view[4]) {
+    if (static_cast<size_t>(view.size()) < kEdidHeaderLength || view[0] || view[1] || view[2] ||
+        view[4]) {
         return {};
     }
 
@@ -164,7 +166,7 @@ Cea861ExtensionBlock parseCea861Block(const byte_view& block) {
         constexpr size_t kDataBlockHeaderSize = 1;
         const size_t dataBlockSize = bodyLength + kDataBlockHeaderSize;
 
-        if (block.size() < dataBlockOffset + dataBlockSize) {
+        if (static_cast<size_t>(block.size()) < dataBlockOffset + dataBlockSize) {
             ALOGW("Invalid EDID: CEA 861 data block is truncated.");
             break;
         }
@@ -264,7 +266,7 @@ std::optional<Edid> parseEdid(const DisplayIdentificationData& edid) {
     }
 
     byte_view view(edid.data(), edid.size());
-    view.remove_prefix(kDescriptorOffset);
+    view = view.subspan(kDescriptorOffset);
 
     std::string_view displayName;
     std::string_view serialNumber;
@@ -274,13 +276,13 @@ std::optional<Edid> parseEdid(const DisplayIdentificationData& edid) {
     constexpr size_t kDescriptorLength = 18;
 
     for (size_t i = 0; i < kDescriptorCount; i++) {
-        if (view.size() < kDescriptorLength) {
+        if (static_cast<size_t>(view.size()) < kDescriptorLength) {
             break;
         }
 
         if (const auto type = getEdidDescriptorType(view)) {
             byte_view descriptor(view.data(), kDescriptorLength);
-            descriptor.remove_prefix(kEdidHeaderLength);
+            descriptor = descriptor.subspan(kEdidHeaderLength);
 
             switch (*type) {
                 case 0xfc:
@@ -295,7 +297,7 @@ std::optional<Edid> parseEdid(const DisplayIdentificationData& edid) {
             }
         }
 
-        view.remove_prefix(kDescriptorLength);
+        view = view.subspan(kDescriptorLength);
     }
 
     std::string_view modelString = displayName;
@@ -327,8 +329,8 @@ std::optional<Edid> parseEdid(const DisplayIdentificationData& edid) {
         const size_t numExtensions = edid[kNumExtensionsOffset];
         view = byte_view(edid.data(), edid.size());
         for (size_t blockNumber = 1; blockNumber <= numExtensions; blockNumber++) {
-            view.remove_prefix(kEdidBlockSize);
-            if (view.size() < kEdidBlockSize) {
+            view = view.subspan(kEdidBlockSize);
+            if (static_cast<size_t>(view.size()) < kEdidBlockSize) {
                 ALOGW("Invalid EDID: block %zu is truncated.", blockNumber);
                 break;
             }

libs/vr/libpdx/private/pdx/rpc/string_wrapper.h

@@ -17,12 +17,12 @@ namespace rpc {
 // C strings more efficient by avoiding unnecessary copies when remote method
 // signatures specify std::basic_string arguments or return values.
 template <typename CharT = std::string::value_type,
-          typename Traits = std::char_traits<CharT>>
+          typename Traits = std::char_traits<std::remove_cv_t<CharT>>>
 class StringWrapper {
  public:
   // Define types in the style of STL strings to support STL operators.
   typedef Traits traits_type;
-  typedef typename Traits::char_type value_type;
+  typedef CharT value_type;
   typedef std::size_t size_type;
   typedef value_type& reference;
   typedef const value_type& const_reference;