Windows install_static refactor.

chrome/install_static/product_install_details.cc

+// Copyright 2016 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 "chrome/install_static/product_install_details.h"
+
+#include <windows.h>
+#include <assert.h>
+
+#include <algorithm>
+
+#include "chrome/install_static/install_modes.h"
+#include "chrome/install_static/install_util.h"
+#include "chrome_elf/nt_registry/nt_registry.h"
+
+namespace install_static {
+
+namespace {
+
+// Returns the executable path for the current process.
+std::wstring GetCurrentProcessExePath() {
+  std::wstring exe_path(MAX_PATH, L'\0');
+  DWORD length = ::GetModuleFileName(nullptr, &exe_path[0], exe_path.size());
+  if (!length)
+    return std::wstring();
+  exe_path.resize(length);
+  return exe_path;
+}
+
+const InstallConstants* FindInstallMode(const std::wstring& suffix) {
+  // Search for a mode with the matching suffix.
+  for (int i = 0; i < NUM_INSTALL_MODES; ++i) {
+    const InstallConstants& mode = kInstallModes[i];
+    if (!_wcsicmp(suffix.c_str(), mode.install_suffix))
+      return &mode;
+  }
+  // The first mode is always the default if all else fails.
+  return &kInstallModes[0];
+}
+
+}  // namespace
+
+void InitializeModuleProductDetails() {
+  InstallDetails::SetForProcess(MakeProductDetails(GetCurrentProcessExePath()));
+}
+
+bool IsPathParentOf(const wchar_t* parent,
+                    size_t parent_len,
+                    const std::wstring& path) {
+  // Ignore all terminating path separators in |parent|.
+  while (parent_len && parent[parent_len - 1] == L'\\')
+    --parent_len;
+  // Pass if the parent was all separators.
+  if (!parent_len)
+    return false;
+  // This is a match if |parent| exactly matches |path| or is followed by a
+  // separator.
+  return !::wcsnicmp(path.c_str(), parent, parent_len) &&
+         (path.size() == parent_len || path[parent_len] == L'\\');
+}
+
+bool PathIsInProgramFiles(const std::wstring& path) {
+  static constexpr const wchar_t* kProgramFilesVariables[] = {
+      L"PROGRAMFILES",  // With or without " (x86)" according to exe bitness.
+      L"PROGRAMFILES(X86)",  // Always "C:\Program Files (x86)"
+      L"PROGRAMW6432",       // Always "C:\Program Files" under WoW64.
+  };
+  wchar_t value[MAX_PATH];

[robertshield, 2016/10/17 05:27:23]

= {} (though it's not really needed here, but to guard against future
refactorings)

[grt (UTC plus 2), 2016/10/24 11:17:51]

added
  *value = L'\0';
on the next line so that it's a properly terminated string. Do you think it's
necessary to zero out the whole thing?

[robertshield, 2016/10/24 14:59:26]

Probably not?  GetEnvironmentVariable is documented as null-terminating the
string that gets returned, so this is probably fine. I'm really just being
paranoid, on account of them being out to get me.

[grt (UTC plus 2), 2016/10/24 19:36:00]

This code uses the length provided by GEV rather than trusting that it's
properly terminated, so I think it's safe. Let me know if it keeps you up and
night and I'll change it.

+  for (const wchar_t* variable : kProgramFilesVariables) {
+    *value = L'\0';
+    DWORD ret = ::GetEnvironmentVariableW(variable, value, _countof(value));
+    if (ret && ret < _countof(value) && IsPathParentOf(value, ret, path))
+      return true;
+  }
+
+  return false;
+}
+
+std::wstring GetInstallSuffix(const std::wstring& exe_path) {
+  // Search backwards from the end of the path for "\Application", using a
+  // manual search for the sake of case-insensitivity.
+  static constexpr wchar_t kInstallBinaryDir[] = L"\\Application";
+  constexpr size_t kInstallBinaryDirLength = _countof(kInstallBinaryDir) - 1;
+  if (exe_path.size() < kProductPathNameLength + kInstallBinaryDirLength)
+    return std::wstring();
+  std::wstring::const_reverse_iterator scan =
+      exe_path.crbegin() + (kInstallBinaryDirLength - 1);
+  while (_wcsnicmp(&*scan, kInstallBinaryDir, kInstallBinaryDirLength) &&
+         ++scan != exe_path.crend()) {
+  }
+  if (scan == exe_path.crend())
+    return std::wstring();
+
+  // Ensure that the dir is followed by a separator or is at the end of the
+  // path.
+  if (scan - exe_path.crbegin() != kInstallBinaryDirLength - 1 &&
+      *(scan - kInstallBinaryDirLength) != L'\\') {
+    return std::wstring();
+  }
+
+  // Scan backwards to the next separator or the beginning of the path.
+  std::wstring::const_reverse_iterator name =
+      std::find(scan + 1, exe_path.crend(), L'\\');
+  // Back up one character to ignore the separator/end of iteration.
+  if (name == exe_path.crend())
+    name = exe_path.crbegin() + exe_path.size() - 1;
+  else
+    --name;
+
+  // Check for a match of the product directory name.
+  if (_wcsnicmp(&*name, kProductPathName, kProductPathNameLength))
+    return std::wstring();
+
+  // Return the (possibly empty) suffix betwixt the product name and install
+  // binary dir.
+  return std::wstring(&*(name - kProductPathNameLength),
+                      (name - scan) - kProductPathNameLength);
+}
+
+bool IsMultiInstall(const InstallConstants& mode, bool system_level) {
+  assert(mode.supports_multi_install);
+  std::wstring args;
+  return nt::QueryRegValueSZ(system_level ? nt::HKLM : nt::HKCU, nt::WOW6432,
+                             GetClientStateKeyPath(mode.app_guid).c_str(),
+                             L"UninstallArguments", &args) &&
+         args.find(L"--multi-install") != std::wstring::npos;
+}
+
+std::unique_ptr<PrimaryInstallDetails> MakeProductDetails(
+    const std::wstring& exe_path) {
+  std::unique_ptr<PrimaryInstallDetails> details(new PrimaryInstallDetails());
+
+  const InstallConstants* mode = FindInstallMode(GetInstallSuffix(exe_path));
+  const bool system_level =
+      mode->supports_system_level && PathIsInProgramFiles(exe_path);
+  const bool multi_install =
+      mode->supports_multi_install && IsMultiInstall(*mode, system_level);
+
+  details->set_mode(mode);
+  details->set_system_level(system_level);
+  details->set_multi_install(multi_install);
+  details->set_channel(DetermineChannel(*mode, system_level, multi_install));
+
+  return details;
+}
+
+}  // namespace install_static