content/browser/indexed_db/docs/open_and_verify_leveldb_database.code2flow

// Copyright 2018 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.

// open_and_verify_leveldb_database.pdf was created from this file by
// https://www.code2flow.com/app

function OpenLevelDB {
  |Read free disk space|;
  Histogram(FreeDiskSpace);
  switch (leveldb_env::OpenDB) {
    case Status Not OK:{
      Histogram(LevelDBOpenErrors);
      if (disk space < 100kb)
        Report disk space as failure reason;
      return leveldb_env::OpenDB error status;
    }
    case Status OK: {
      Histogram(LevelDB.OpenTime);
      return Status::OK;
    }
  }
}

OpenAndVerifyLevelDBDatabase;
switch (Create IDB Directory) {
  case Failure:
    Histogram(FAILED_DIRECTORY);
    return IOError("Unable to create IndexedDB database path");
  case Success:
}
Create File path & blob path;
if (File Path is too long) {
  Histogram(ORIGIN_TOO_LONG);
  return IOError("File path too long);
}

call OpenLevelDB;

switch(OpenLevelDB status) {
  case IOError:
    Histogram(OPEN_NO_RECOVERY);
    return OpenLevelDB error status;
  case Corruption:
    Set data loss info;
    break;
  case OK:
    if (Corruption Info Exists & Last Open was corrupt) {
      Histogram(FAILED_PRIOR_CORRUPTION);
      db_.reset();
      Populate data loss info
      (previous corruption);
      break;
    }
    switch (try to read schema) {
      case Failure reading schema:
        Histogram(FAILED_IO_ERROR_CHECKING_SCHEMA);
        db_.reset();
        Populate data loss info
        (schema checking failure);
        break;
      case Schema is unknown:
        Histogram(FAILED_UNKNOWN_SCHEMA);
        db_.reset();
        Populate data loss info
        (unknown schema);
        break;
      case Success & Valid:
        Histogram(OPEN_SUCCESS);
        goto end;
    }
}
switch(DestroyLevelDB(file_path)) {
  case Not OK:
    Histogram(CLEANUP_DESTROY_FAILED);
    return DestroyLevelDB error status;
  case OK:
}
call OpenLevelDB;
switch(OpenLevelDB status) {
  case Not OK:
    Histogram(CLEANUP_REOPEN_FAILED);
    return OpenLevelDB error status;
  case OK:
    Histogram(CLEANUP_REOPEN_SUCCESS);
}

end:
Histogram(OPEN_SUCCESS);
block {
Create BackingStore;
switch (Parse schema & metadata) {
  case Failure:
    Delete Database & BackingStore;
    break;
  case Success:
    if (Should we clean blob journal?) {
    switch(CleanUpBlobJournal) {
      case OK:
        report `Status::OK`;
        goto done;
      case Not OK:
        Histogram(FAILED_CLEANUP_JOURNAL_ERROR);
        return CleanUpBlobJournal error status;
    }
  }
}
return BackingStore error status;
}

done:
return done;