1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/storage/src/FileSystemModule.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,304 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
1.5 + * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
1.6 + * This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#include "FileSystemModule.h"
1.11 +
1.12 +#include "sqlite3.h"
1.13 +#include "nsString.h"
1.14 +#include "nsISimpleEnumerator.h"
1.15 +#include "nsIFile.h"
1.16 +
1.17 +namespace {
1.18 +
1.19 +struct VirtualTableCursorBase
1.20 +{
1.21 + VirtualTableCursorBase()
1.22 + {
1.23 + memset(&mBase, 0, sizeof(mBase));
1.24 + }
1.25 +
1.26 + sqlite3_vtab_cursor mBase;
1.27 +};
1.28 +
1.29 +struct VirtualTableCursor : public VirtualTableCursorBase
1.30 +{
1.31 +public:
1.32 + VirtualTableCursor()
1.33 + : mRowId(-1)
1.34 + {
1.35 + mCurrentFileName.SetIsVoid(true);
1.36 + }
1.37 +
1.38 + const nsString& DirectoryPath() const
1.39 + {
1.40 + return mDirectoryPath;
1.41 + }
1.42 +
1.43 + const nsString& CurrentFileName() const
1.44 + {
1.45 + return mCurrentFileName;
1.46 + }
1.47 +
1.48 + int64_t RowId() const
1.49 + {
1.50 + return mRowId;
1.51 + }
1.52 +
1.53 + nsresult Init(const nsAString& aPath);
1.54 + nsresult NextFile();
1.55 +
1.56 +private:
1.57 + nsCOMPtr<nsISimpleEnumerator> mEntries;
1.58 +
1.59 + nsString mDirectoryPath;
1.60 + nsString mCurrentFileName;
1.61 +
1.62 + int64_t mRowId;
1.63 +};
1.64 +
1.65 +nsresult
1.66 +VirtualTableCursor::Init(const nsAString& aPath)
1.67 +{
1.68 + nsCOMPtr<nsIFile> directory =
1.69 + do_CreateInstance(NS_LOCAL_FILE_CONTRACTID);
1.70 + NS_ENSURE_TRUE(directory, NS_ERROR_FAILURE);
1.71 +
1.72 + nsresult rv = directory->InitWithPath(aPath);
1.73 + NS_ENSURE_SUCCESS(rv, rv);
1.74 +
1.75 + rv = directory->GetPath(mDirectoryPath);
1.76 + NS_ENSURE_SUCCESS(rv, rv);
1.77 +
1.78 + rv = directory->GetDirectoryEntries(getter_AddRefs(mEntries));
1.79 + NS_ENSURE_SUCCESS(rv, rv);
1.80 +
1.81 + rv = NextFile();
1.82 + NS_ENSURE_SUCCESS(rv, rv);
1.83 +
1.84 + return NS_OK;
1.85 +}
1.86 +
1.87 +nsresult
1.88 +VirtualTableCursor::NextFile()
1.89 +{
1.90 + bool hasMore;
1.91 + nsresult rv = mEntries->HasMoreElements(&hasMore);
1.92 + NS_ENSURE_SUCCESS(rv, rv);
1.93 +
1.94 + if (!hasMore) {
1.95 + mCurrentFileName.SetIsVoid(true);
1.96 + return NS_OK;
1.97 + }
1.98 +
1.99 + nsCOMPtr<nsISupports> entry;
1.100 + rv = mEntries->GetNext(getter_AddRefs(entry));
1.101 + NS_ENSURE_SUCCESS(rv, rv);
1.102 +
1.103 + nsCOMPtr<nsIFile> file = do_QueryInterface(entry);
1.104 + NS_ENSURE_TRUE(file, NS_ERROR_FAILURE);
1.105 +
1.106 + rv = file->GetLeafName(mCurrentFileName);
1.107 + NS_ENSURE_SUCCESS(rv, rv);
1.108 +
1.109 + mRowId++;
1.110 +
1.111 + return NS_OK;
1.112 +}
1.113 +
1.114 +int Connect(sqlite3* aDB, void* aAux, int aArgc, const char* const* aArgv,
1.115 + sqlite3_vtab** aVtab, char** aErr)
1.116 +{
1.117 + static const char virtualTableSchema[] =
1.118 + "CREATE TABLE fs ("
1.119 + "name TEXT, "
1.120 + "path TEXT"
1.121 + ")";
1.122 +
1.123 + int rc = sqlite3_declare_vtab(aDB, virtualTableSchema);
1.124 + if (rc != SQLITE_OK) {
1.125 + return rc;
1.126 + }
1.127 +
1.128 + sqlite3_vtab* vt = new sqlite3_vtab();
1.129 + memset(vt, 0, sizeof(*vt));
1.130 +
1.131 + *aVtab = vt;
1.132 +
1.133 + return SQLITE_OK;
1.134 +}
1.135 +
1.136 +int Disconnect(sqlite3_vtab* aVtab )
1.137 +{
1.138 + delete aVtab;
1.139 +
1.140 + return SQLITE_OK;
1.141 +}
1.142 +
1.143 +int BestIndex(sqlite3_vtab* aVtab, sqlite3_index_info* aInfo)
1.144 +{
1.145 + // Here we specify what index constraints we want to handle. That is, there
1.146 + // might be some columns with particular constraints in which we can help
1.147 + // SQLite narrow down the result set.
1.148 + //
1.149 + // For example, take the "path = x" where x is a directory. In this case,
1.150 + // we can narrow our search to just this directory instead of the entire file
1.151 + // system. This can be a significant optimization. So, we want to handle that
1.152 + // constraint. To do so, we would look for two specific input conditions:
1.153 + //
1.154 + // 1. aInfo->aConstraint[i].iColumn == 1
1.155 + // 2. aInfo->aConstraint[i].op == SQLITE_INDEX_CONSTRAINT_EQ
1.156 + //
1.157 + // The first states that the path column is being used in one of the input
1.158 + // constraints and the second states that the constraint involves the equal
1.159 + // operator.
1.160 + //
1.161 + // An even more specific search would be for name='xxx', in which case we
1.162 + // can limit the search to a single file, if it exists.
1.163 + //
1.164 + // What we have to do here is look for all of our index searches and select
1.165 + // the narrowest. We can only pick one, so obviously we want the one that
1.166 + // is the most specific, which leads to the smallest result set.
1.167 +
1.168 + for(int i = 0; i < aInfo->nConstraint; i++) {
1.169 + if (aInfo->aConstraint[i].iColumn == 1 && aInfo->aConstraint[i].usable) {
1.170 + if (aInfo->aConstraint[i].op & SQLITE_INDEX_CONSTRAINT_EQ) {
1.171 + aInfo->aConstraintUsage[i].argvIndex = 1;
1.172 + }
1.173 + break;
1.174 + }
1.175 +
1.176 + // TODO: handle single files (constrained also by the name column)
1.177 + }
1.178 +
1.179 + return SQLITE_OK;
1.180 +}
1.181 +
1.182 +int Open(sqlite3_vtab* aVtab, sqlite3_vtab_cursor** aCursor)
1.183 +{
1.184 + VirtualTableCursor* cursor = new VirtualTableCursor();
1.185 +
1.186 + *aCursor = reinterpret_cast<sqlite3_vtab_cursor*>(cursor);
1.187 +
1.188 + return SQLITE_OK;
1.189 +}
1.190 +
1.191 +int Close(sqlite3_vtab_cursor* aCursor)
1.192 +{
1.193 + VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
1.194 +
1.195 + delete cursor;
1.196 +
1.197 + return SQLITE_OK;
1.198 +}
1.199 +
1.200 +int Filter(sqlite3_vtab_cursor* aCursor, int aIdxNum, const char* aIdxStr,
1.201 + int aArgc, sqlite3_value** aArgv)
1.202 +{
1.203 + VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
1.204 +
1.205 + if(aArgc <= 0) {
1.206 + return SQLITE_OK;
1.207 + }
1.208 +
1.209 + nsDependentString path(
1.210 + reinterpret_cast<const char16_t*>(::sqlite3_value_text16(aArgv[0])));
1.211 +
1.212 + nsresult rv = cursor->Init(path);
1.213 + NS_ENSURE_SUCCESS(rv, SQLITE_ERROR);
1.214 +
1.215 + return SQLITE_OK;
1.216 +}
1.217 +
1.218 +int Next(sqlite3_vtab_cursor* aCursor)
1.219 +{
1.220 + VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
1.221 +
1.222 + nsresult rv = cursor->NextFile();
1.223 + NS_ENSURE_SUCCESS(rv, SQLITE_ERROR);
1.224 +
1.225 + return SQLITE_OK;
1.226 +}
1.227 +
1.228 +int Eof(sqlite3_vtab_cursor* aCursor)
1.229 +{
1.230 + VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
1.231 + return cursor->CurrentFileName().IsVoid() ? 1 : 0;
1.232 +}
1.233 +
1.234 +int Column(sqlite3_vtab_cursor* aCursor, sqlite3_context* aContext,
1.235 + int aColumnIndex)
1.236 +{
1.237 + VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
1.238 +
1.239 + switch (aColumnIndex) {
1.240 + // name
1.241 + case 0: {
1.242 + const nsString& name = cursor->CurrentFileName();
1.243 + sqlite3_result_text16(aContext, name.get(),
1.244 + name.Length() * sizeof(char16_t),
1.245 + SQLITE_TRANSIENT);
1.246 + break;
1.247 + }
1.248 +
1.249 + // path
1.250 + case 1: {
1.251 + const nsString& path = cursor->DirectoryPath();
1.252 + sqlite3_result_text16(aContext, path.get(),
1.253 + path.Length() * sizeof(char16_t),
1.254 + SQLITE_TRANSIENT);
1.255 + break;
1.256 + }
1.257 + default:
1.258 + NS_NOTREACHED("Unsupported column!");
1.259 + }
1.260 +
1.261 + return SQLITE_OK;
1.262 +}
1.263 +
1.264 +int RowId(sqlite3_vtab_cursor* aCursor, sqlite3_int64* aRowid)
1.265 +{
1.266 + VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
1.267 +
1.268 + *aRowid = cursor->RowId();
1.269 +
1.270 + return SQLITE_OK;
1.271 +}
1.272 +
1.273 +} // anonymous namespace
1.274 +
1.275 +namespace mozilla {
1.276 +namespace storage {
1.277 +
1.278 +int RegisterFileSystemModule(sqlite3* aDB, const char* aName)
1.279 +{
1.280 + static sqlite3_module module = {
1.281 + 1,
1.282 + Connect,
1.283 + Connect,
1.284 + BestIndex,
1.285 + Disconnect,
1.286 + Disconnect,
1.287 + Open,
1.288 + Close,
1.289 + Filter,
1.290 + Next,
1.291 + Eof,
1.292 + Column,
1.293 + RowId,
1.294 + nullptr,
1.295 + nullptr,
1.296 + nullptr,
1.297 + nullptr,
1.298 + nullptr,
1.299 + nullptr,
1.300 + nullptr
1.301 + };
1.302 +
1.303 + return sqlite3_create_module(aDB, aName, &module, nullptr);
1.304 +}
1.305 +
1.306 +} // namespace storage
1.307 +} // namespace mozilla
