[Payments] Add web app manifest section table in SQLite web database

components/payments/android/web_app_manifest_section_table.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 "components/payments/android/web_app_manifest_section_table.h"
+
+#include <stdint.h>
+
+#include <memory>
+
+#include "base/logging.h"
+#include "sql/statement.h"
+#include "sql/transaction.h"
+
+namespace payments {
+namespace {
+
+// Note that the fingerprint is calculated with SHA-256.
+const size_t kFingerPrintLength = 32;
+
+WebDatabaseTable::TypeKey GetKey() {
+  // We just need a unique constant. Use the address of a static that
+  // COMDAT folding won't touch in an optimizing linker.
+  static int table_key = 0;
+  return reinterpret_cast<void*>(&table_key);
+}
+
+// Converts 2-dimensional vector |fingerprints| to 1-dimesional vector.
+std::unique_ptr<std::vector<uint8_t>> SerializeFingerPrints(
+    const std::vector<std::vector<uint8_t>>& fingerprints) {
+  auto serialized_fingerprints = base::MakeUnique<std::vector<uint8_t>>();
+
+  for (const auto& fingerprint : fingerprints) {
+    DCHECK_EQ(fingerprint.size(), kFingerPrintLength);
+    serialized_fingerprints->insert(serialized_fingerprints->end(),
+                                    fingerprint.begin(), fingerprint.end());
+  }
+
+  return serialized_fingerprints;
+}
+
+// Converts 1-dimensional vector created by SerializeFingerPrints back to
+// 2-dimensional vector. Each vector of the second dimensional vector has exact
+// kFingerPrintLength number of elements.
+bool DeserializeFingerPrints(
+    const std::vector<uint8_t>& fingerprints,
+    std::vector<std::vector<uint8_t>>& deserialized_fingerprints) {
+  if (fingerprints.size() % kFingerPrintLength != 0)
+    return false;
+
+  for (size_t i = 0; i < fingerprints.size(); i += kFingerPrintLength) {
+    deserialized_fingerprints.emplace_back(
+        fingerprints.begin() + i,
+        fingerprints.begin() + i + kFingerPrintLength);
+  }
+  return true;
+}
+
+}  // namespace
+
+WebAppManifestSectionTable::WebAppManifestSectionTable() {}
+
+WebAppManifestSectionTable::~WebAppManifestSectionTable() {}
+
+WebAppManifestSectionTable* WebAppManifestSectionTable::FromWebDatabase(
+    WebDatabase* db) {
+  return static_cast<WebAppManifestSectionTable*>(db->GetTable(GetKey()));
+}
+
+WebDatabaseTable::TypeKey WebAppManifestSectionTable::GetTypeKey() const {
+  return GetKey();
+}
+
+bool WebAppManifestSectionTable::CreateTablesIfNecessary() {
+  if (!db_->Execute("CREATE TABLE IF NOT EXISTS web_app_manifest_section ( "
+                    "id VARCHAR, "
+                    "min_version INTEGER NOT NULL DEFAULT 0, "
+                    "fingerprints BLOB) ")) {
+    NOTREACHED();
+    return false;
+  }
+
+  return true;
+}
+
+bool WebAppManifestSectionTable::IsSyncable() {
+  return false;
+}
+
+bool WebAppManifestSectionTable::MigrateToVersion(
+    int version,
+    bool* update_compatible_version) {
+  return true;
+}
+
+bool WebAppManifestSectionTable::AddWebAppManifest(
+    mojom::WebAppManifestSection* manifest) {
+  DCHECK(manifest != nullptr);
+  if (manifest->id.empty())
+    return false;
+
+  sql::Transaction transaction(db_);
+  if (!transaction.Begin())
+    return false;
+
+  sql::Statement s1(db_->GetUniqueStatement(
+      "DELETE FROM web_app_manifest_section WHERE id=?"));
+  s1.BindString(0, manifest->id);
+  if (!s1.Run())
+    return false;
+
+  sql::Statement s2(
+      db_->GetUniqueStatement("INSERT INTO web_app_manifest_section "
+                              "(id, min_version, fingerprints) "
+                              "VALUES (?, ?, ?)"));
+  int index = 0;
+  s2.BindString(index++, manifest->id);
+  s2.BindInt64(index++, manifest->min_version);
+  std::unique_ptr<std::vector<uint8_t>> serialized_fingerprints =
+      SerializeFingerPrints(manifest->fingerprints);
+  s2.BindBlob(index, serialized_fingerprints->data(),
+              serialized_fingerprints->size());
+  if (!s2.Run())
+    return false;
+
+  if (!transaction.Commit())
+    return false;
+
+  return true;
+}
+
+mojom::WebAppManifestSectionPtr WebAppManifestSectionTable::GetWebAppManifest(
+    std::string web_app) {
+  sql::Statement s(
+      db_->GetUniqueStatement("SELECT id, min_version, fingerprints "
+                              "FROM web_app_manifest_section "
+                              "WHERE id=?"
+                              "LIMIT 1"));

[Scott Hess - ex-Googler, 2017/04/11 19:31:46]

Why are you doing the LIMIT 1, here?

Oooooh.  Shouldn't you have a unique index on [id]?  Then you could also use
INSERT OR REPLACE in AddWebAppManifest(), which would allow you to drop the
DELETE and remove the explicit sql::Transaction (because the INSERT OR REPLACE
is implicitly atomic).

[gogerald1, 2017/04/11 21:53:30]

Done.

+  s.BindString(0, web_app);
+
+  if (!s.is_valid())
+    return nullptr;

[Scott Hess - ex-Googler, 2017/04/11 19:31:46]

This is implicit in s.Step().  It will return |false| if the statement is
invalid.  There are a few edge cases involving testing of error-handling which
sometimes need an explicit is_valid() test, but if you don't need it, best to
drop it.

Also, Chromium style below would be to if(!s.Step()) return nullptr, then
un-nest the current if() block.

[gogerald1, 2017/04/11 21:53:30]

Done.

+
+  if (s.Step()) {
+    mojom::WebAppManifestSectionPtr manifest =
+        mojom::WebAppManifestSection::New();
+
+    int index = 0;
+    manifest->id = s.ColumnString(index++);
+    manifest->min_version = s.ColumnInt64(index++);
+
+    std::vector<uint8_t> fingerprints;
+    if (!s.ColumnBlobAsVector(index, &fingerprints))
+      return nullptr;
+
+    if (!DeserializeFingerPrints(fingerprints, manifest->fingerprints))
+      return nullptr;
+
+    return manifest;
+  }
+
+  return nullptr;
+}
+
+}  // payments