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