add a download slices table into history download db

components/history/core/browser/download_database.cc

Index: components/history/core/browser/download_database.cc
diff --git a/components/history/core/browser/download_database.cc b/components/history/core/browser/download_database.cc
index 5994bf5e2564fcf5b8d27d9ef830866cedaa29d0..0bc7dd9d67d240bf8bd954ab4f708b7de5008ece 100644
--- a/components/history/core/browser/download_database.cc
+++ b/components/history/core/browser/download_database.cc
@@ -66,6 +66,11 @@ base::FilePath ColumnFilePath(sql::Statement& statement, int col) {
 
 }  // namespace
 
+// static
+bool DownloadDatabase::IsParallelDownloadingEnabled() {
+  return base::FeatureList::IsEnabled(kParallelDownloading);
+}
+
 DownloadDatabase::DownloadDatabase(
     DownloadInterruptReason download_interrupt_reason_none,
     DownloadInterruptReason download_interrupt_reason_crash)
@@ -312,15 +317,21 @@ bool DownloadDatabase::InitDownloadTable() {
       "url LONGVARCHAR NOT NULL, "          // URL.
       "PRIMARY KEY (id, chain_index) )";
 
+  bool ret;
   if (GetDB().DoesTableExist("downloads")) {
-    return EnsureColumnExists("end_time", "INTEGER NOT NULL DEFAULT 0") &&
-           EnsureColumnExists("opened", "INTEGER NOT NULL DEFAULT 0");
+    ret = EnsureColumnExists("end_time", "INTEGER NOT NULL DEFAULT 0") &&
+        EnsureColumnExists("opened", "INTEGER NOT NULL DEFAULT 0");
   } else {
     // If the "downloads" table doesn't exist, the downloads_url_chain
-    // table better not.
-    return (!GetDB().DoesTableExist("downloads_url_chain") &&
-            GetDB().Execute(kSchema) && GetDB().Execute(kUrlChainSchema));
+    // and the downloads_jobs table better not.
+    ret = !GetDB().DoesTableExist("downloads_url_chain") &&
+        !GetDB().DoesTableExist("downloads_jobs") &&
+        GetDB().Execute(kSchema) && GetDB().Execute(kUrlChainSchema);
   }
+  if (IsParallelDownloadingEnabled())
+    ret = ret && EnsureDownloadJobsTableExists();
+
+  return ret;
 }
 
 uint32_t DownloadDatabase::GetNextDownloadId() {
@@ -473,6 +484,39 @@ void DownloadDatabase::QueryDownloads(std::vector<DownloadRow>* results) {
     url_chain->push_back(GURL(statement_chain.ColumnString(2)));
   }
 
+  if (IsParallelDownloadingEnabled()) {

[asanka, 2017/02/01 22:34:10]

The DB schema shouldn't depend on a feature state.

It's okay to rev up the schema version. Doing so lets us know when we introduced
this table and will be important if we want to modify/remove it later.

Also, it doesn't matter that the feature isn't available by default on the
stable channel.

[qinmin, 2017/02/01 23:37:26]

removed all feature state checking in this file. So the downloads_jobs table
will now always be created. But the table and DownloadRow.download_job_info will
always be empty until we launch this feature

+    sql::Statement statement_download_job(GetDB().GetCachedStatement(
+        SQL_FROM_HERE,
+        "SELECT id, job_id, start_position, length, received_bytes, "
+        "state, interrupt_reason FROM downloads_jobs "
+        "ORDER BY id, job_id"));
+
+    while (statement_download_job.Step()) {
+      int column = 0;
+      // See the comment above about SQLITE lacking unsigned integers.
+      int64_t signed_id = statement_download_job.ColumnInt64(column++);
+      if (signed_id <= static_cast<int64_t>(kInvalidDownloadId))
+        continue;
+      int id = IntToDownloadId(signed_id);
+      DownloadJobInfo info;
+      info.id = IntToDownloadId(signed_id);
+      info.job_id = statement_download_job.ColumnInt(column++);
+      info.start_position = statement_download_job.ColumnInt64(column++);
+      info.length = statement_download_job.ColumnInt64(column++);
+      info.received_bytes = statement_download_job.ColumnInt64(column++);
+      info.state = IntToDownloadState(
+          statement_download_job.ColumnInt(column++));
+      info.interrupt_reason = IntToDownloadInterruptReason(
+          statement_download_job.ColumnInt(column++));
+      // Confirm the id has already been seen--if it hasn't, discard the
+      // record.
+      DCHECK(base::ContainsKey(info_map, id));
+      if (!base::ContainsKey(info_map, id))
+        continue;
+      info_map[id]->download_job_info.push_back(info);
+    }
+  }
+
   for (std::map<uint32_t, DownloadRow*>::iterator it = info_map.begin();
        it != info_map.end(); ++it) {
     DownloadRow* row = it->second;
@@ -533,7 +577,17 @@ bool DownloadDatabase::UpdateDownload(const DownloadRow& data) {
   statement.BindString(column++, data.last_modified);
   statement.BindInt(column++, DownloadIdToInt(data.id));
 
-  return statement.Run();
+  if (!statement.Run())
+    return false;
+
+  if (IsParallelDownloadingEnabled()) {
+    for (size_t i = 0; i < data.download_job_info.size(); ++i) {
+      if (!UpdateDownloadJob(data.id, data.download_job_info[i], false))
+        return false;
+    }
+  }
+
+  return true;
 }
 
 void DownloadDatabase::EnsureInProgressEntriesCleanedUp() {
@@ -548,6 +602,19 @@ void DownloadDatabase::EnsureInProgressEntriesCleanedUp() {
   statement.BindInt(2, DownloadStateToInt(DownloadState::IN_PROGRESS));
 
   statement.Run();
+
+  if (IsParallelDownloadingEnabled()) {
+    sql::Statement statement_download_job(GetDB().GetCachedStatement(
+        SQL_FROM_HERE,
+        "UPDATE downloads_jobs SET state=?, interrupt_reason=? WHERE state=?"));
+    statement_download_job.BindInt(
+        0, DownloadStateToInt(DownloadState::INTERRUPTED));
+    statement_download_job.BindInt(
+        1, DownloadInterruptReasonToInt(download_interrupt_reason_crash_));
+    statement_download_job.BindInt(
+        2, DownloadStateToInt(DownloadState::IN_PROGRESS));
+    statement_download_job.Run();
+  }
   in_progress_entry_cleanup_completed_ = true;
 }
 
@@ -650,6 +717,16 @@ bool DownloadDatabase::CreateDownload(const DownloadRow& info) {
     }
     statement_insert_chain.Reset(true);
   }
+
+  if (IsParallelDownloadingEnabled()) {
+    for (size_t i = 0; i < info.download_job_info.size(); ++i) {
+      if (!UpdateDownloadJob(info.id, info.download_job_info[i], true)) {
+        RemoveDownload(info.id);
+        return false;
+      }
+    }
+  }
+
   return true;
 }
 
@@ -665,6 +742,9 @@ void DownloadDatabase::RemoveDownload(uint32_t id) {
     return;
   }
   RemoveDownloadURLs(id);
+  if (IsParallelDownloadingEnabled()) {
+    RemoveDownloadJobs(id);
+  }
 }
 
 void DownloadDatabase::RemoveDownloadURLs(uint32_t id) {
@@ -686,4 +766,88 @@ size_t DownloadDatabase::CountDownloads() {
   return statement.ColumnInt(0);
 }
 
+bool DownloadDatabase::EnsureDownloadJobsTableExists() {
+  // TODO(qinmin): increment the current history database version by 1 once
+  // this feature is no longer experimental.
+  const char kJobsSchema[] =
+      "CREATE TABLE downloads_jobs ("
+      "id INTEGER NOT NULL,"                // downloads.id.
+      "job_id INTEGER NOT NULL,"            // Download job id.
+      "start_position INTEGER NOT NULL,"    // The start request position of the
+                                            // download job.
+      "length INTEGER NOT NULL,"            // length of the request, -1
+                                            // if not specified
+      "received_bytes INTEGER NOT NULL,"    // Total bytes downloaded.
+      "state INTEGER NOT NULL,"             // To be determined.
+      "interrupt_reason INTEGER NOT NULL, " // DownloadInterruptReason
+      "PRIMARY KEY (id, job_id) )";
+
+  return GetDB().DoesTableExist("downloads_jobs") ||
+      GetDB().Execute(kJobsSchema);
+}
+
+bool DownloadDatabase::UpdateDownloadJob(
+    const DownloadJobInfo& info, bool is_new_download) {
+  sql::Statement statement_query(GetDB().GetCachedStatement(
+      SQL_FROM_HERE,
+      "SELECT count(*) "
+      "FROM downloads_jobs "
+      "WHERE id=? AND job_id=?"));
+  statement_query.BindInt(0, info.id);
+  statement_query.BindInt(1, info.job_id);
+
+  bool job_exists = false;
+  if (statement_query.Step()) {
+    job_exists = statement_query.ColumnInt(0) > 0;
+    // There should not be any jobs in downloads_jobs for this id.  If there
+    // are, we don't want them to interfere with inserting the correct jobs,
+    // so just remove them.
+    if (is_new_download && job_exists)
+      RemoveDownloadJobs(info.id);
+  }
+  int column = 0;
+
+  if (!is_new_download && job_exists) {
+    sql::Statement statement_update(GetDB().GetCachedStatement(
+        SQL_FROM_HERE,
+        "UPDATE downloads_jobs "
+        "SET start_position=?, length=?, received_bytes=?, state=?, "
+        "interrupt_reason=? "
+        "WHERE id=? AND job_id=?"));
+    statement_update.BindInt64(column++, info.start_position);
+    statement_update.BindInt64(column++, info.length);
+    statement_update.BindInt64(column++, info.received_bytes);
+    statement_update.BindInt(column++, DownloadStateToInt(info.state));
+    statement_update.BindInt(
+        column++, DownloadInterruptReasonToInt(info.interrupt_reason));
+    statement_update.BindInt(column++, info.id);
+    statement_update.BindInt(column++, info.job_id);
+    return statement_update.Run();
+  } else {
+    sql::Statement statement_insert(GetDB().GetCachedStatement(
+        SQL_FROM_HERE,
+        "INSERT INTO downloads_jobs "
+        "(id, job_id, start_position, length, received_bytes, state, "
+        "interrupt_reason) "
+        "VALUES (?, ?, ?, ?, ?, ?, ?)"));
+    statement_insert.BindInt(column++, info.id);
+    statement_insert.BindInt(column++, info.job_id);
+    statement_insert.BindInt64(column++, info.start_position);
+    statement_insert.BindInt64(column++, info.length);
+    statement_insert.BindInt64(column++, info.received_bytes);
+    statement_insert.BindInt(column++, DownloadStateToInt(info.state));
+    statement_insert.BindInt(
+        column++, DownloadInterruptReasonToInt(info.interrupt_reason));
+
+    return statement_insert.Run();
+  }
+}
+
+void DownloadDatabase::RemoveDownloadJobs(uint32_t id) {
+  sql::Statement statement_delete(GetDB().GetCachedStatement(SQL_FROM_HERE,
+      "DELETE FROM downloads_jobs WHERE id=?"));
+  statement_delete.BindInt(0, id);
+  statement_delete.Run();
+}
+
 }  // namespace history