The Tor Browser: comparison storage/src/FileSystemModule.cpp

--1:000000000000
+:e8e2a53ec5a7
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+* vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+* This Source Code Form is subject to the terms of the Mozilla Public
+* License, v. 2.0. If a copy of the MPL was not distributed with this
+* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include "FileSystemModule.h"
+#include "sqlite3.h"
+#include "nsString.h"
+#include "nsISimpleEnumerator.h"
+#include "nsIFile.h"
+namespace {
+struct VirtualTableCursorBase
+{
+VirtualTableCursorBase()
+{
+memset(&mBase, 0, sizeof(mBase));
+}
+sqlite3_vtab_cursor mBase;
+};
+struct VirtualTableCursor : public VirtualTableCursorBase
+{
+public:
+VirtualTableCursor()
+: mRowId(-1)
+{
+mCurrentFileName.SetIsVoid(true);
+}
+const nsString& DirectoryPath() const
+{
+return mDirectoryPath;
+}
+const nsString& CurrentFileName() const
+{
+return mCurrentFileName;
+}
+int64_t RowId() const
+{
+return mRowId;
+}
+nsresult Init(const nsAString& aPath);
+nsresult NextFile();
+private:
+nsCOMPtr<nsISimpleEnumerator> mEntries;
+nsString mDirectoryPath;
+nsString mCurrentFileName;
+int64_t mRowId;
+};
+nsresult
+VirtualTableCursor::Init(const nsAString& aPath)
+{
+nsCOMPtr<nsIFile> directory =
+do_CreateInstance(NS_LOCAL_FILE_CONTRACTID);
+NS_ENSURE_TRUE(directory, NS_ERROR_FAILURE);
+nsresult rv = directory->InitWithPath(aPath);
+NS_ENSURE_SUCCESS(rv, rv);
+rv = directory->GetPath(mDirectoryPath);
+NS_ENSURE_SUCCESS(rv, rv);
+rv = directory->GetDirectoryEntries(getter_AddRefs(mEntries));
+NS_ENSURE_SUCCESS(rv, rv);
+rv = NextFile();
+NS_ENSURE_SUCCESS(rv, rv);
+return NS_OK;
+}
+nsresult
+VirtualTableCursor::NextFile()
+{
+bool hasMore;
+nsresult rv = mEntries->HasMoreElements(&hasMore);
+NS_ENSURE_SUCCESS(rv, rv);
+if (!hasMore) {
+mCurrentFileName.SetIsVoid(true);
+return NS_OK;
+}
+nsCOMPtr<nsISupports> entry;
+rv = mEntries->GetNext(getter_AddRefs(entry));
+NS_ENSURE_SUCCESS(rv, rv);
+nsCOMPtr<nsIFile> file = do_QueryInterface(entry);
+NS_ENSURE_TRUE(file, NS_ERROR_FAILURE);
+rv = file->GetLeafName(mCurrentFileName);
+NS_ENSURE_SUCCESS(rv, rv);
+mRowId++;
+return NS_OK;
+}
+int Connect(sqlite3* aDB, void* aAux, int aArgc, const char* const* aArgv,
+sqlite3_vtab** aVtab, char** aErr)
+{
+static const char virtualTableSchema[] =
+"CREATE TABLE fs ("
+"name TEXT, "
+"path TEXT"
+")";
+int rc = sqlite3_declare_vtab(aDB, virtualTableSchema);
+if (rc != SQLITE_OK) {
+return rc;
+}
+sqlite3_vtab* vt = new sqlite3_vtab();
+memset(vt, 0, sizeof(*vt));
+*aVtab = vt;
+return SQLITE_OK;
+}
+int Disconnect(sqlite3_vtab* aVtab )
+{
+delete aVtab;
+return SQLITE_OK;
+}
+int BestIndex(sqlite3_vtab* aVtab, sqlite3_index_info* aInfo)
+{
+// Here we specify what index constraints we want to handle. That is, there
+// might be some columns with particular constraints in which we can help
+// SQLite narrow down the result set.
+//
+// For example, take the "path = x" where x is a directory. In this case,
+// we can narrow our search to just this directory instead of the entire file
+// system. This can be a significant optimization. So, we want to handle that
+// constraint. To do so, we would look for two specific input conditions:
+//
+// 1. aInfo->aConstraint[i].iColumn == 1
+// 2. aInfo->aConstraint[i].op == SQLITE_INDEX_CONSTRAINT_EQ
+//
+// The first states that the path column is being used in one of the input
+// constraints and the second states that the constraint involves the equal
+// operator.
+//
+// An even more specific search would be for name='xxx', in which case we
+// can limit the search to a single file, if it exists.
+//
+// What we have to do here is look for all of our index searches and select
+// the narrowest. We can only pick one, so obviously we want the one that
+// is the most specific, which leads to the smallest result set.
+for(int i = 0; i < aInfo->nConstraint; i++) {
+if (aInfo->aConstraint[i].iColumn == 1 && aInfo->aConstraint[i].usable) {
+if (aInfo->aConstraint[i].op & SQLITE_INDEX_CONSTRAINT_EQ) {
+aInfo->aConstraintUsage[i].argvIndex = 1;
+}
+break;
+}
+// TODO: handle single files (constrained also by the name column)
+}
+return SQLITE_OK;
+}
+int Open(sqlite3_vtab* aVtab, sqlite3_vtab_cursor** aCursor)
+{
+VirtualTableCursor* cursor = new VirtualTableCursor();
+*aCursor = reinterpret_cast<sqlite3_vtab_cursor*>(cursor);
+return SQLITE_OK;
+}
+int Close(sqlite3_vtab_cursor* aCursor)
+{
+VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+delete cursor;
+return SQLITE_OK;
+}
+int Filter(sqlite3_vtab_cursor* aCursor, int aIdxNum, const char* aIdxStr,
+int aArgc, sqlite3_value** aArgv)
+{
+VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+if(aArgc <= 0) {
+return SQLITE_OK;
+}
+nsDependentString path(
+reinterpret_cast<const char16_t*>(::sqlite3_value_text16(aArgv[0])));
+nsresult rv = cursor->Init(path);
+NS_ENSURE_SUCCESS(rv, SQLITE_ERROR);
+return SQLITE_OK;
+}
+int Next(sqlite3_vtab_cursor* aCursor)
+{
+VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+nsresult rv = cursor->NextFile();
+NS_ENSURE_SUCCESS(rv, SQLITE_ERROR);
+return SQLITE_OK;
+}
+int Eof(sqlite3_vtab_cursor* aCursor)
+{
+VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+return cursor->CurrentFileName().IsVoid() ? 1 : 0;
+}
+int Column(sqlite3_vtab_cursor* aCursor, sqlite3_context* aContext,
+int aColumnIndex)
+{
+VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+switch (aColumnIndex) {
+// name
+case 0: {
+const nsString& name = cursor->CurrentFileName();
+sqlite3_result_text16(aContext, name.get(),
+name.Length() * sizeof(char16_t),
+SQLITE_TRANSIENT);
+break;
+}
+// path
+case 1: {
+const nsString& path = cursor->DirectoryPath();
+sqlite3_result_text16(aContext, path.get(),
+path.Length() * sizeof(char16_t),
+SQLITE_TRANSIENT);
+break;
+}
+default:
+NS_NOTREACHED("Unsupported column!");
+}
+return SQLITE_OK;
+}
+int RowId(sqlite3_vtab_cursor* aCursor, sqlite3_int64* aRowid)
+{
+VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+*aRowid = cursor->RowId();
+return SQLITE_OK;
+}
+} // anonymous namespace
+namespace mozilla {
+namespace storage {
+int RegisterFileSystemModule(sqlite3* aDB, const char* aName)
+{
+static sqlite3_module module = {
+1,
+Connect,
+Connect,
+BestIndex,
+Disconnect,
+Disconnect,
+Open,
+Close,
+Filter,
+Next,
+Eof,
+Column,
+RowId,
+nullptr,
+nullptr,
+nullptr,
+nullptr,
+nullptr,
+nullptr,
+nullptr
+};
+return sqlite3_create_module(aDB, aName, &module, nullptr);
+}
+} // namespace storage
+} // namespace mozilla

The Tor Browser / file comparison

comparison: storage/src/FileSystemModule.cpp

storage/src/FileSystemModule.cpp