Precache tracking database

components/precache/core/precache_url_table.cc

Index: components/precache/core/precache_url_table.cc
diff --git a/components/precache/core/precache_url_table.cc b/components/precache/core/precache_url_table.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3a6b409d51db70d23bc0e20d734875bbea0a05ea
--- /dev/null
+++ b/components/precache/core/precache_url_table.cc
@@ -0,0 +1,115 @@
+// Copyright 2013 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/precache/core/precache_url_table.h"
+
+#include <string>
+
+#include "base/logging.h"
+#include "base/strings/stringprintf.h"
+#include "sql/connection.h"
+#include "sql/statement.h"
+
+using sql::Statement;
+
+namespace {
+
+const char kUrlTableName[] = "precache_urls";

[Scott Hess - ex-Googler, 2013/11/19 18:47:48]

Same comment as for stats table.

[sclittle, 2013/11/19 23:27:10]

Done.

+
+// Returns the spec of the given URL.
+std::string GetKey(const GURL& url) {
+  return url.spec();
+}
+
+}  // namespace
+
+namespace precache {
+
+PrecacheURLTable::PrecacheURLTable() : db_(NULL) {}
+
+PrecacheURLTable::~PrecacheURLTable() {}
+
+void PrecacheURLTable::Init(sql::Connection* db) {
+  DCHECK(!db_);  // Init must only be called once.
+  DCHECK(db);    // The database connection must be non-NULL.
+  db_ = db;
+  CreateTableIfNonExistent();
+}
+
+void PrecacheURLTable::AddURL(const GURL& url,
+                              const base::Time& precache_time) {
+  DCHECK(db_);

[Scott Hess - ex-Googler, 2013/11/19 18:47:48]

I think all of these DCHECK(db_) can be gotten rid of.  Every method immediately
dereferences db_, so it will only provide a trivial improvement to diagnostics.

[sclittle, 2013/11/19 23:27:10]

Done.

+
+  Statement statement(db_->GetCachedStatement(
+      SQL_FROM_HERE,
+      base::StringPrintf("INSERT OR REPLACE INTO %s (url, time) VALUES(?,?)",
+                         kUrlTableName).c_str()));
+
+  statement.BindString(0, GetKey(url));
+  statement.BindInt64(1, precache_time.ToInternalValue());
+  statement.Run();
+}
+
+bool PrecacheURLTable::HasURL(const GURL& url) {
+  DCHECK(db_);
+
+  Statement statement(db_->GetCachedStatement(
+      SQL_FROM_HERE, base::StringPrintf("SELECT time FROM %s WHERE url=?",
+                                        kUrlTableName).c_str()));
+
+  statement.BindString(0, GetKey(url));
+  return statement.Step();
+}
+
+void PrecacheURLTable::DeleteURL(const GURL& url) {
+  DCHECK(db_);
+
+  Statement statement(db_->GetCachedStatement(
+      SQL_FROM_HERE,
+      base::StringPrintf("DELETE FROM %s WHERE url=?", kUrlTableName).c_str()));
+
+  statement.BindString(0, GetKey(url));
+  statement.Run();
+}
+
+void PrecacheURLTable::DeleteAllPrecachedBefore(const base::Time& delete_end) {
+  DCHECK(db_);
+
+  Statement statement(db_->GetCachedStatement(
+      SQL_FROM_HERE, base::StringPrintf("DELETE FROM %s WHERE time < ?",
+                                        kUrlTableName).c_str()));
+
+  statement.BindInt64(0, delete_end.ToInternalValue());
+  statement.Run();
+}
+
+void PrecacheURLTable::GetAllDataForTesting(std::map<GURL, base::Time>* map) {
+  DCHECK(db_);
+  DCHECK(map);  // |map| must not be NULL.
+  map->clear();
+
+  Statement statement(db_->GetCachedStatement(
+      SQL_FROM_HERE,
+      base::StringPrintf("SELECT url, time FROM %s", kUrlTableName).c_str()));
+
+  while (statement.Step()) {
+    GURL url = GURL(statement.ColumnString(0));
+    (*map)[url] = base::Time::FromInternalValue(statement.ColumnInt64(1));
+  }
+}
+
+void PrecacheURLTable::CreateTableIfNonExistent() {
+  DCHECK(db_);
+
+  if (db_->DoesTableExist(kUrlTableName))

[Scott Hess - ex-Googler, 2013/11/19 18:47:48]

Same comment as for stats table.

[sclittle, 2013/11/19 23:27:10]

Done.

+    return;
+
+  if (!db_->Execute(base::StringPrintf(
+           "CREATE TABLE %s (url TEXT, time INTEGER, PRIMARY KEY(url))",

[Scott Hess - ex-Googler, 2013/11/19 18:47:48]

"url TEXT PRIMARY KEY" should work fine here.

[sclittle, 2013/11/19 23:27:10]

Done.

+           kUrlTableName).c_str())) {
+    DLOG(WARNING) << "Could not create precache URL table in database.";

[Scott Hess - ex-Googler, 2013/11/19 18:47:48]

Note that the sql/ library is going to complain loudly if this fails in debug
mode.

[sclittle, 2013/11/19 23:27:10]

Good point; if this fails in debug mode, Execute() would DLOG(FATAL), so this
warning would never be printed.

+  }
+}
+
+}  // namespace precache