Use std::string in DeviceProductInfo and serialize it as Flattenable

Use std::string instead of fixed size char arrays. Serialize
DeviceProductInfo and DisplayInfo as Flattenable instead of using
memcpy().

Bug: 145299597
Test: 1. m
      2. adb shell dumpsys display
      3. check that DeviceProductInfo is correctly populated
Change-Id: Id21186138b39d7bb167c41ff7ee9387081ac6285

9 files changed, 216 insertions, 36 deletions

diff --git a/libs/gui/ISurfaceComposer.cpp b/libs/gui/ISurfaceComposer.cpp
index 04c21a9e1d..e1c112aaed 100644
--- a/libs/gui/ISurfaceComposer.cpp
+++ b/libs/gui/ISurfaceComposer.cpp
@@ -371,10 +371,8 @@ public:
         data.writeStrongBinder(display);
         remote()->transact(BnSurfaceComposer::GET_DISPLAY_INFO, data, &reply);
         const status_t result = reply.readInt32();
-        if (result == NO_ERROR) {
-            memcpy(info, reply.readInplace(sizeof(DisplayInfo)), sizeof(DisplayInfo));
-        }
-        return result;
+        if (result != NO_ERROR) return result;
+        return reply.read(*info);
     }
 
     virtual status_t getDisplayConfigs(const sp<IBinder>& display, Vector<DisplayConfig>* configs) {
@@ -1377,10 +1375,8 @@ status_t BnSurfaceComposer::onTransact(
             const sp<IBinder> display = data.readStrongBinder();
             const status_t result = getDisplayInfo(display, &info);
             reply->writeInt32(result);
-            if (result == NO_ERROR) {
-                memcpy(reply->writeInplace(sizeof(DisplayInfo)), &info, sizeof(DisplayInfo));
-            }
-            return NO_ERROR;
+            if (result != NO_ERROR) return result;
+            return reply->write(info);
         }
         case GET_DISPLAY_CONFIGS: {
             CHECK_INTERFACE(ISurfaceComposer, data, reply);
diff --git a/libs/ui/Android.bp b/libs/ui/Android.bp
index 9f7f36f848..3965cf0025 100644
--- a/libs/ui/Android.bp
+++ b/libs/ui/Android.bp
@@ -46,7 +46,7 @@ cc_library_static {
 
     apex_available: [
         "//apex_available:anyapex",
-	"//apex_available:platform",
+        "//apex_available:platform",
     ],
     shared_libs: [
         "libutils",
@@ -97,6 +97,8 @@ cc_library_shared {
         "BufferHubEventFd.cpp",
         "BufferHubMetadata.cpp",
         "DebugUtils.cpp",
+        "DeviceProductInfo.cpp",
+        "DisplayInfo.cpp",
         "Fence.cpp",
         "FenceTime.cpp",
         "FrameStats.cpp",
diff --git a/libs/ui/DeviceProductInfo.cpp b/libs/ui/DeviceProductInfo.cpp
new file mode 100644
index 0000000000..efd61b6111
--- /dev/null
+++ b/libs/ui/DeviceProductInfo.cpp
@@ -0,0 +1,50 @@
+/*
+ * Copyright 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <ui/DeviceProductInfo.h>
+
+#include <ui/FlattenableHelpers.h>
+
+namespace android {
+
+size_t DeviceProductInfo::getFlattenedSize() const {
+    return FlattenableHelpers::getFlattenedSize(name) + sizeof(manufacturerPnpId) +
+            FlattenableHelpers::getFlattenedSize(productId) + sizeof(manufactureOrModelDate);
+}
+
+status_t DeviceProductInfo::flatten(void* buffer, size_t size) const {
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
+    FlattenableHelpers::write(buffer, size, name);
+    FlattenableUtils::write(buffer, size, manufacturerPnpId);
+    FlattenableHelpers::write(buffer, size, productId);
+    FlattenableUtils::write(buffer, size, manufactureOrModelDate);
+    return NO_ERROR;
+}
+
+status_t DeviceProductInfo::unflatten(void const* buffer, size_t size) {
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
+    FlattenableHelpers::read(buffer, size, &name);
+    FlattenableUtils::read(buffer, size, manufacturerPnpId);
+    FlattenableHelpers::read(buffer, size, &productId);
+    FlattenableUtils::read(buffer, size, manufactureOrModelDate);
+    return NO_ERROR;
+}
+
+} // namespace android
diff --git a/libs/ui/DisplayInfo.cpp b/libs/ui/DisplayInfo.cpp
new file mode 100644
index 0000000000..6ed7e19690
--- /dev/null
+++ b/libs/ui/DisplayInfo.cpp
@@ -0,0 +1,54 @@
+/*
+ * Copyright 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <ui/DisplayInfo.h>
+
+#include <cstdint>
+
+#include <ui/FlattenableHelpers.h>
+
+namespace android {
+
+size_t DisplayInfo::getFlattenedSize() const {
+    return sizeof(connectionType) + sizeof(density) + sizeof(secure) +
+            FlattenableHelpers::getFlattenedSize(deviceProductInfo);
+}
+
+status_t DisplayInfo::flatten(void* buffer, size_t size) const {
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
+    FlattenableUtils::write(buffer, size, connectionType);
+    FlattenableUtils::write(buffer, size, density);
+    FlattenableUtils::write(buffer, size, secure);
+    FlattenableHelpers::write(buffer, size, deviceProductInfo);
+
+    return NO_ERROR;
+}
+
+status_t DisplayInfo::unflatten(void const* buffer, size_t size) {
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
+    FlattenableUtils::read(buffer, size, connectionType);
+    FlattenableUtils::read(buffer, size, density);
+    FlattenableUtils::read(buffer, size, secure);
+    FlattenableHelpers::read(buffer, size, &deviceProductInfo);
+
+    return NO_ERROR;
+}
+
+} // namespace android
diff --git a/libs/ui/include/ui/DeviceProductInfo.h b/libs/ui/include/ui/DeviceProductInfo.h
index c396e738b9..cc5ebe4311 100644
--- a/libs/ui/include/ui/DeviceProductInfo.h
+++ b/libs/ui/include/ui/DeviceProductInfo.h
@@ -19,8 +19,12 @@
 #include <array>
 #include <cstdint>
 #include <optional>
+#include <string>
+#include <type_traits>
 #include <variant>
 
+#include <utils/Flattenable.h>
+
 namespace android {
 
 // NUL-terminated plug and play ID.
@@ -29,9 +33,7 @@ using PnpId = std::array<char, 4>;
 // Product-specific information about the display or the directly connected device on the
 // display chain. For example, if the display is transitively connected, this field may contain
 // product information about the intermediate device.
-struct DeviceProductInfo {
-    static constexpr size_t TEXT_BUFFER_SIZE = 20;
-
+struct DeviceProductInfo : LightFlattenable<DeviceProductInfo> {
     struct ModelYear {
         uint32_t year;
     };
@@ -44,16 +46,22 @@ struct DeviceProductInfo {
     };
 
     // Display name.
-    std::array<char, TEXT_BUFFER_SIZE> name;
+    std::string name;
 
     // Manufacturer Plug and Play ID.
     PnpId manufacturerPnpId;
 
     // Manufacturer product ID.
-    std::array<char, TEXT_BUFFER_SIZE> productId;
+    std::string productId;
 
     using ManufactureOrModelDate = std::variant<ModelYear, ManufactureYear, ManufactureWeekAndYear>;
+    static_assert(std::is_trivially_copyable_v<ManufactureOrModelDate>);
     ManufactureOrModelDate manufactureOrModelDate;
+
+    bool isFixedSize() const { return false; }
+    size_t getFlattenedSize() const;
+    status_t flatten(void* buffer, size_t size) const;
+    status_t unflatten(void const* buffer, size_t size);
 };
 
 } // namespace android
diff --git a/libs/ui/include/ui/DisplayInfo.h b/libs/ui/include/ui/DisplayInfo.h
index 897060c2ed..03e0a3886e 100644
--- a/libs/ui/include/ui/DisplayInfo.h
+++ b/libs/ui/include/ui/DisplayInfo.h
@@ -20,19 +20,23 @@
 #include <type_traits>
 
 #include <ui/DeviceProductInfo.h>
+#include <utils/Flattenable.h>
 
 namespace android {
 
 enum class DisplayConnectionType { Internal, External };
 
 // Immutable information about physical display.
-struct DisplayInfo {
+struct DisplayInfo : LightFlattenable<DisplayInfo> {
     DisplayConnectionType connectionType = DisplayConnectionType::Internal;
     float density = 0.f;
     bool secure = false;
     std::optional<DeviceProductInfo> deviceProductInfo;
-};
 
-static_assert(std::is_trivially_copyable_v<DisplayInfo>);
+    bool isFixedSize() const { return false; }
+    size_t getFlattenedSize() const;
+    status_t flatten(void* buffer, size_t size) const;
+    status_t unflatten(void const* buffer, size_t size);
+};
 
 } // namespace android
diff --git a/libs/ui/include_private/ui/FlattenableHelpers.h b/libs/ui/include_private/ui/FlattenableHelpers.h
new file mode 100644
index 0000000000..bdf480478a
--- /dev/null
+++ b/libs/ui/include_private/ui/FlattenableHelpers.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <optional>
+#include <type_traits>
+
+#include <utils/Flattenable.h>
+
+namespace android {
+
+struct FlattenableHelpers {
+    // Flattenable helpers for reading and writing std::string
+    static size_t getFlattenedSize(const std::string& str) { return str.length() + 1; }
+
+    static void write(void*& buffer, size_t& size, const std::string& str) {
+        strcpy(reinterpret_cast<char*>(buffer), str.c_str());
+        FlattenableUtils::advance(buffer, size, getFlattenedSize(str));
+    }
+
+    static void read(void const*& buffer, size_t& size, std::string* str) {
+        str->assign(reinterpret_cast<const char*>(buffer));
+        FlattenableUtils::advance(buffer, size, getFlattenedSize(*str));
+    }
+
+    // Flattenable utils for reading and writing std::optional
+    template <class T, typename = std::enable_if_t<std::is_base_of_v<LightFlattenable<T>, T>>>
+    static size_t getFlattenedSize(const std::optional<T>& value) {
+        return sizeof(bool) + (value ? value->getFlattenedSize() : 0);
+    }
+
+    template <class T, typename = std::enable_if_t<std::is_base_of_v<LightFlattenable<T>, T>>>
+    static void write(void*& buffer, size_t& size, const std::optional<T>& value) {
+        if (value) {
+            FlattenableUtils::write(buffer, size, true);
+            value->flatten(buffer, size);
+            FlattenableUtils::advance(buffer, size, value->getFlattenedSize());
+        } else {
+            FlattenableUtils::write(buffer, size, false);
+        }
+    }
+
+    template <class T, typename = std::enable_if_t<std::is_base_of_v<LightFlattenable<T>, T>>>
+    static void read(void const*& buffer, size_t& size, std::optional<T>* value) {
+        bool isPresent;
+        FlattenableUtils::read(buffer, size, isPresent);
+        if (isPresent) {
+            *value = T();
+            (*value)->unflatten(buffer, size);
+            FlattenableUtils::advance(buffer, size, (*value)->getFlattenedSize());
+        } else {
+            value->reset();
+        }
+    }
+};
+
+} // namespace android
diff --git a/services/surfaceflinger/DisplayHardware/DisplayIdentification.cpp b/services/surfaceflinger/DisplayHardware/DisplayIdentification.cpp
index f24f3142f1..63897cc102 100644
--- a/services/surfaceflinger/DisplayHardware/DisplayIdentification.cpp
+++ b/services/surfaceflinger/DisplayHardware/DisplayIdentification.cpp
@@ -70,12 +70,8 @@ char getPnpLetter(uint16_t id) {
 
 DeviceProductInfo buildDeviceProductInfo(const Edid& edid) {
     DeviceProductInfo info;
-    std::copy(edid.displayName.begin(), edid.displayName.end(), info.name.begin());
-    info.name[edid.displayName.size()] = '\0';
-
-    const auto productId = std::to_string(edid.productId);
-    std::copy(productId.begin(), productId.end(), info.productId.begin());
-    info.productId[productId.size()] = '\0';
+    info.name.assign(edid.displayName);
+    info.productId = std::to_string(edid.productId);
     info.manufacturerPnpId = edid.pnpId;
 
     constexpr uint8_t kModelYearFlag = 0xff;
@@ -181,7 +177,6 @@ std::optional<Edid> parseEdid(const DisplayIdentificationData& edid) {
 
     constexpr size_t kDescriptorCount = 4;
     constexpr size_t kDescriptorLength = 18;
-    static_assert(kDescriptorLength - kEdidHeaderLength < DeviceProductInfo::TEXT_BUFFER_SIZE);
 
     for (size_t i = 0; i < kDescriptorCount; i++) {
         if (view.size() < kDescriptorLength) {
diff --git a/services/surfaceflinger/tests/unittests/DisplayIdentificationTest.cpp b/services/surfaceflinger/tests/unittests/DisplayIdentificationTest.cpp
index c2ddfcee45..2c7a28164a 100644
--- a/services/surfaceflinger/tests/unittests/DisplayIdentificationTest.cpp
+++ b/services/surfaceflinger/tests/unittests/DisplayIdentificationTest.cpp
@@ -293,9 +293,9 @@ TEST(DisplayIdentificationTest, deviceProductInfo) {
         ASSERT_TRUE(displayIdInfo);
         ASSERT_TRUE(displayIdInfo->deviceProductInfo);
         const auto& info = *displayIdInfo->deviceProductInfo;
-        EXPECT_STREQ("", info.name.data());
+        EXPECT_EQ("", info.name);
         EXPECT_STREQ("SEC", info.manufacturerPnpId.data());
-        EXPECT_STREQ("12610", info.productId.data());
+        EXPECT_EQ("12610", info.productId);
         ASSERT_TRUE(std::holds_alternative<ManufactureYear>(info.manufactureOrModelDate));
         EXPECT_EQ(2011, std::get<ManufactureYear>(info.manufactureOrModelDate).year);
     }
@@ -304,9 +304,9 @@ TEST(DisplayIdentificationTest, deviceProductInfo) {
         ASSERT_TRUE(displayIdInfo);
         ASSERT_TRUE(displayIdInfo->deviceProductInfo);
         const auto& info = *displayIdInfo->deviceProductInfo;
-        EXPECT_STREQ("HP ZR30w", info.name.data());
+        EXPECT_EQ("HP ZR30w", info.name);
         EXPECT_STREQ("HWP", info.manufacturerPnpId.data());
-        EXPECT_STREQ("10348", info.productId.data());
+        EXPECT_EQ("10348", info.productId);
         ASSERT_TRUE(std::holds_alternative<ManufactureWeekAndYear>(info.manufactureOrModelDate));
         const auto& date = std::get<ManufactureWeekAndYear>(info.manufactureOrModelDate);
         EXPECT_EQ(2012, date.year);
@@ -317,9 +317,9 @@ TEST(DisplayIdentificationTest, deviceProductInfo) {
         ASSERT_TRUE(displayIdInfo);
         ASSERT_TRUE(displayIdInfo->deviceProductInfo);
         const auto& info = *displayIdInfo->deviceProductInfo;
-        EXPECT_STREQ("SAMSUNG", info.name.data());
+        EXPECT_EQ("SAMSUNG", info.name);
         EXPECT_STREQ("SAM", info.manufacturerPnpId.data());
-        EXPECT_STREQ("2302", info.productId.data());
+        EXPECT_EQ("2302", info.productId);
         ASSERT_TRUE(std::holds_alternative<ManufactureWeekAndYear>(info.manufactureOrModelDate));
         const auto& date = std::get<ManufactureWeekAndYear>(info.manufactureOrModelDate);
         EXPECT_EQ(2011, date.year);
@@ -330,9 +330,9 @@ TEST(DisplayIdentificationTest, deviceProductInfo) {
         ASSERT_TRUE(displayIdInfo);
         ASSERT_TRUE(displayIdInfo->deviceProductInfo);
         const auto& info = *displayIdInfo->deviceProductInfo;
-        EXPECT_STREQ("Panasonic-TV", info.name.data());
+        EXPECT_EQ("Panasonic-TV", info.name);
         EXPECT_STREQ("MEI", info.manufacturerPnpId.data());
-        EXPECT_STREQ("41622", info.productId.data());
+        EXPECT_EQ("41622", info.productId);
         ASSERT_TRUE(std::holds_alternative<ManufactureYear>(info.manufactureOrModelDate));
         const auto& date = std::get<ManufactureYear>(info.manufactureOrModelDate);
         EXPECT_EQ(2019, date.year);
@@ -342,9 +342,9 @@ TEST(DisplayIdentificationTest, deviceProductInfo) {
         ASSERT_TRUE(displayIdInfo);
         ASSERT_TRUE(displayIdInfo->deviceProductInfo);
         const auto& info = *displayIdInfo->deviceProductInfo;
-        EXPECT_STREQ("Hisense", info.name.data());
+        EXPECT_EQ("Hisense", info.name);
         EXPECT_STREQ("HEC", info.manufacturerPnpId.data());
-        EXPECT_STREQ("0", info.productId.data());
+        EXPECT_EQ("0", info.productId);
         ASSERT_TRUE(std::holds_alternative<ManufactureWeekAndYear>(info.manufactureOrModelDate));
         const auto& date = std::get<ManufactureWeekAndYear>(info.manufactureOrModelDate);
         EXPECT_EQ(2019, date.year);
@@ -355,9 +355,9 @@ TEST(DisplayIdentificationTest, deviceProductInfo) {
         ASSERT_TRUE(displayIdInfo);
         ASSERT_TRUE(displayIdInfo->deviceProductInfo);
         const auto& info = *displayIdInfo->deviceProductInfo;
-        EXPECT_STREQ("LP2361", info.name.data());
+        EXPECT_EQ("LP2361", info.name);
         EXPECT_STREQ("CTL", info.manufacturerPnpId.data());
-        EXPECT_STREQ("9373", info.productId.data());
+        EXPECT_EQ("9373", info.productId);
         ASSERT_TRUE(std::holds_alternative<ModelYear>(info.manufactureOrModelDate));
         EXPECT_EQ(2013, std::get<ModelYear>(info.manufactureOrModelDate).year);
     }