Set up a Basic "view" Command

BUG=1168231

Change-Id: I9f46b03f3c03a50382778c8d8ae404be8714ab31
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2644316
Auto-Submit: Robert Liao <robliao@chromium.org>
Reviewed-by: Wei Li <weili@chromium.org>
Commit-Queue: Robert Liao <robliao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#846202}

tools/win/chromeexts/BUILD.gn

@@ -10,6 +10,8 @@ shared_library("chromeexts") {
     "chromeexts.def",
     "commands/hwnd_command.cc",
     "commands/hwnd_command.h",
+    "commands/view_command.cc",
+    "commands/view_command.h",
   ]
 
   deps = [ "//base" ]

tools/win/chromeexts/chromeexts.cc

@@ -7,6 +7,7 @@
 
 #include "tools/win/chromeexts/chrome_exts_command.h"
 #include "tools/win/chromeexts/commands/hwnd_command.h"
+#include "tools/win/chromeexts/commands/view_command.h"
 
 namespace {
 using Microsoft::WRL::ComPtr;
@@ -38,3 +39,8 @@ HRESULT CALLBACK RunHwndCommand(IDebugClient* client, PCSTR args) {
   return tools::win::chromeexts::ChromeExtsCommand::Run<
       tools::win::chromeexts::HwndCommand>(client, args);
 }
+
+HRESULT CALLBACK RunViewCommand(IDebugClient* client, PCSTR args) {
+  return tools::win::chromeexts::ChromeExtsCommand::Run<
+      tools::win::chromeexts::ViewCommand>(client, args);
+}

tools/win/chromeexts/chromeexts.def

@@ -9,3 +9,4 @@ EXPORTS
   DebugExtensionUninitialize
   help
   hwnd = RunHwndCommand
+  view = RunViewCommand

tools/win/chromeexts/commands/view_command.cc

+// Copyright 2021 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "tools/win/chromeexts/commands/view_command.h"
+
+#include <dbgeng.h>
+#include <windows.h>
+#include <wrl/client.h>
+
+#include <string>
+#include <vector>
+
+#include "base/strings/utf_string_conversions.h"
+
+namespace tools {
+namespace win {
+namespace chromeexts {
+
+namespace {
+
+using Microsoft::WRL::ComPtr;
+
+class VirtualMemoryBlock {
+ public:
+  VirtualMemoryBlock(IDebugClient* debug_client,
+                     const std::string symbol,
+                     uint64_t address) {
+    unsigned long type_size;
+    if (FAILED(debug_client->QueryInterface(IID_PPV_ARGS(&symbols_))) ||
+        FAILED(
+            symbols_->GetSymbolTypeId(symbol.c_str(), &type_id_, &module_)) ||
+        FAILED(symbols_->GetTypeSize(module_, type_id_, &type_size))) {
+      return;
+    }
+
+    ComPtr<IDebugDataSpaces> data;
+    if (FAILED(symbols_.As(&data))) {
+      return;
+    }
+
+    storage_.resize(type_size);
+    data->ReadVirtual(address, storage_.data(), type_size, nullptr);
+  }
+
+  ~VirtualMemoryBlock() = default;
+
+  template <typename T>
+  T GetFieldValue(std::string field_name) const {
+    unsigned long field_type_id;
+    unsigned long field_offset;
+    unsigned long field_size;
+    if (FAILED(symbols_->GetFieldTypeAndOffset(
+            module_, type_id_, field_name.c_str(), &field_type_id,
+            &field_offset)) ||
+        FAILED(symbols_->GetTypeSize(module_, field_type_id, &field_size))) {
+      return T();
+    }
+
+    return *reinterpret_cast<const T*>(storage_.data() + field_offset);
+  }
+
+  VirtualMemoryBlock GetFieldMemoryBlock(std::string field_name) const {
+    unsigned long field_type_id;
+    unsigned long field_offset;
+    unsigned long field_size;
+    if (FAILED(symbols_->GetFieldTypeAndOffset(
+            module_, type_id_, field_name.c_str(), &field_type_id,
+            &field_offset)) ||
+        FAILED(symbols_->GetTypeSize(module_, field_type_id, &field_size))) {
+      return VirtualMemoryBlock();
+    }
+    VirtualMemoryBlock field;
+    field.symbols_ = symbols_;
+    auto start = storage_.cbegin() + field_offset;
+    auto end = start + field_size;
+    field.storage_ = std::vector<char>(start, end);
+    field.module_ = module_;
+    field.type_id_ = field_type_id;
+    return field;
+  }
+
+ private:
+  VirtualMemoryBlock() = default;
+
+  ComPtr<IDebugSymbols3> symbols_;
+  std::vector<char> storage_;
+  uint64_t module_ = 0;
+  unsigned long type_id_ = 0;
+};
+
+}  // namespace
+
+ViewCommand::ViewCommand() = default;
+
+ViewCommand::~ViewCommand() = default;
+
+HRESULT ViewCommand::Execute() {
+  auto remaining_arguments = command_line().GetArgs();
+  if (remaining_arguments.size() > 1) {
+    Printf("Unexpected number of arguments %d\n", remaining_arguments.size());
+  }
+
+  DEBUG_VALUE address_debug_value{};
+  if (FAILED(GetDebugClientAs<IDebugControl>()->Evaluate(
+          base::WideToASCII(remaining_arguments[0]).c_str(), DEBUG_VALUE_INT64,
+          &address_debug_value, nullptr))) {
+    Printf("Unevaluatable Expression %ws", remaining_arguments[0].c_str());
+  }
+
+  uint64_t address = reinterpret_cast<uint64_t>(address_debug_value.I64);
+
+  VirtualMemoryBlock view_block(GetDebugClientAs<IDebugClient>().Get(),
+                                "views!views::View", address);
+  VirtualMemoryBlock bounds_block = view_block.GetFieldMemoryBlock("bounds_");
+  VirtualMemoryBlock origin_block = bounds_block.GetFieldMemoryBlock("origin_");
+  VirtualMemoryBlock size_block = bounds_block.GetFieldMemoryBlock("size_");
+  Printf("Bounds: %d,%d (%dx%d)\n", origin_block.GetFieldValue<int>("x_"),
+         origin_block.GetFieldValue<int>("y_"),
+         size_block.GetFieldValue<int>("width_"),
+         size_block.GetFieldValue<int>("height_"));
+  Printf("Parent: 0x%08x\n", view_block.GetFieldValue<intptr_t>("parent_"));
+
+  return S_OK;
+}
+
+}  // namespace chromeexts
+}  // namespace win
+}  // namespace tools

tools/win/chromeexts/commands/view_command.h

+// Copyright 2021 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef TOOLS_WIN_CHROMEEXTS_COMMANDS_VIEW_COMMAND_H_
+#define TOOLS_WIN_CHROMEEXTS_COMMANDS_VIEW_COMMAND_H_
+
+#include "tools/win/chromeexts/chrome_exts_command.h"
+
+namespace tools {
+namespace win {
+namespace chromeexts {
+
+class ViewCommand : public ChromeExtsCommand {
+ public:
+  ViewCommand();
+  ViewCommand(const ViewCommand&) = delete;
+  ViewCommand& operator=(const ViewCommand&) = delete;
+  ~ViewCommand() override;
+
+ protected:
+  HRESULT Execute() override;
+};
+
+}  // namespace chromeexts
+}  // namespace win
+}  // namespace tools
+
+#endif  // TOOLS_WIN_CHROMEEXTS_COMMANDS_VIEW_COMMAND_H_