Add a utility class to retrieve the components of an MSI product

chrome/browser/conflicts/msi_util_win.cc

+// Copyright 2017 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/browser/conflicts/msi_util_win.h"
+
+#include <windows.h>
+
+#include <msi.h>
+#include <msiquery.h>
+
+#include <utility>
+
+#include "base/strings/string_util.h"
+#include "base/threading/thread_restrictions.h"
+
+namespace {
+
+// Retrieves the file path to the product's installer.
+bool GetMsiPath(const base::string16& product_guid, base::string16* result) {
+  DWORD buffer_size = 0;
+  if (::MsiGetProductInfo(product_guid.c_str(), INSTALLPROPERTY_LOCALPACKAGE,

[chrisha1, 2017/05/05 20:01:40]

Document that you're querying first for the required buffer length.

OR

If you know this is typically less than say, MAX_PATH, then you could start with
a string of this size and only call out a second time if the result doesn't fit.

[Patrick Monette, 2017/05/06 00:54:37]

Done. Let me know if you have any idea to make the code looks nicer.

+                          L"", &buffer_size) != ERROR_MORE_DATA)
+    return false;
+
+  // Must account for the null terminator.
+  buffer_size++;
+
+  return ::MsiGetProductInfo(product_guid.c_str(), INSTALLPROPERTY_LOCALPACKAGE,
+                             base::WriteInto(result, buffer_size),
+                             &buffer_size) == ERROR_SUCCESS;
+}
+
+// Returns the string value at position |index| in the given |record_handle|.
+// Note that columns are 1-indexed.
+bool GetRecordString(MSIHANDLE record_handle,
+                     size_t index,
+                     base::string16* result) {
+  DWORD buffer_size = 0;
+  if (::MsiRecordGetString(record_handle, index, L"", &buffer_size) !=
+      ERROR_MORE_DATA)
+    return false;
+
+  // Must account for the null terminator.
+  buffer_size++;

[chrisha1, 2017/05/05 20:01:40]

Ditto for this read. If you have reason to believe there's a reasonable starting
buffer size, start with that to minimize round trips.

[Patrick Monette, 2017/05/06 00:54:37]

Done.

+
+  return ::MsiRecordGetString(record_handle, index,
+                              base::WriteInto(result, buffer_size),
+                              &buffer_size) == ERROR_SUCCESS;
+}
+
+// Inspects the installer file and extracts the component guids. Each .msi file
+// is actually an SQL database.
+bool GetMsiComponentGuids(const base::string16& msi_database_path,
+                          std::vector<base::string16>* component_guids) {
+  PMSIHANDLE msi_database_handle;
+  if (::MsiOpenDatabase(msi_database_path.c_str(), MSIDBOPEN_READONLY,
+                        &msi_database_handle) != ERROR_SUCCESS) {
+    return false;
+  }
+
+  PMSIHANDLE components_view_handle;
+  if (::MsiDatabaseOpenView(msi_database_handle,
+                            L"SELECT ComponentId FROM Component",
+                            &components_view_handle) != ERROR_SUCCESS) {
+    return false;
+  }
+
+  if (::MsiViewExecute(components_view_handle, 0) != ERROR_SUCCESS)
+    return false;
+
+  PMSIHANDLE record_handle;
+  while (::MsiViewFetch(components_view_handle, &record_handle) ==
+         ERROR_SUCCESS) {
+    // The record only have the ComponentId column, and its index is 1.
+    base::string16 component_guid;
+    if (GetRecordString(record_handle, 1, &component_guid))
+      component_guids->push_back(std::move(component_guid));
+  }
+
+  return true;
+}
+
+// Retrieves the |path| to the given component.
+bool GetMsiComponentPath(const base::string16& product_guid,
+                         const base::string16& component_guid,
+                         base::string16* path) {
+  DWORD buffer_size = 0;
+  if (::MsiGetComponentPath(product_guid.c_str(), component_guid.c_str(), L"",

[chrisha1, 2017/05/05 20:01:40]

Ditto.

[Patrick Monette, 2017/05/06 00:54:37]

Done.

+                            &buffer_size) != INSTALLSTATE_MOREDATA) {
+    return false;
+  }
+
+  // Must account for the null terminator.
+  buffer_size++;
+
+  return ::MsiGetComponentPath(product_guid.c_str(), component_guid.c_str(),
+                               base::WriteInto(path, buffer_size),
+                               &buffer_size) == INSTALLSTATE_LOCAL;
+}
+
+}  // namespace
+
+// The most efficient way to get the list of components associated to an
+// installed product is to inspect the installer file. A copy of the installer
+// exists somewhere on the file system because Windows needs it to uninstall the
+// product.
+//
+// So this function retrieves the path to the installer, extract the component

[chrisha1, 2017/05/05 20:01:40]

extracts*

[Patrick Monette, 2017/05/06 00:54:37]

Done.

+// GUIDS from it, and uses those to find the path of each component.
+bool MsiUtil::GetMsiComponentPaths(
+    const base::string16& product_guid,
+    std::vector<base::string16>* component_paths) {
+  base::ThreadRestrictions::AssertIOAllowed();
+
+  base::string16 msi_path;
+  if (!GetMsiPath(product_guid, &msi_path))
+    return false;
+
+  std::vector<base::string16> component_guids;
+  if (!GetMsiComponentGuids(msi_path, &component_guids))
+    return false;
+
+  for (const auto& component_guid : component_guids) {
+    base::string16 component_path;
+    if (!GetMsiComponentPath(product_guid, component_guid, &component_path))
+      continue;
+
+    component_paths->push_back(std::move(component_path));
+  }
+
+  return true;
+}