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/* -*- 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
#include "FileSystemModule.h"
#include "sqlite3.h"
#include "nsComponentManagerUtils.h"
#include "nsString.h"
#include "nsIDirectoryEnumerator.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<nsIDirectoryEnumerator> 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;
}
const char16_t* value =
static_cast<const char16_t*>(::sqlite3_value_text16(aArgv[0]));
nsDependentString path(value,
::sqlite3_value_bytes16(aArgv[0]) / sizeof(char16_t));
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:
MOZ_ASSERT_UNREACHABLE("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;
}
} // 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