file_systems/bfs/Index.cpp

/*
 * Copyright 2001-2017, Axel Dörfler, axeld@pinc-software.de.
 * This file may be used under the terms of the MIT License.
 */


//! Index access functions


#include "Index.h"

#include <file_systems/QueryParserUtils.h>

#include "Debug.h"
#include "Volume.h"
#include "Inode.h"
#include "BPlusTree.h"


Index::Index(Volume* volume)
	:
	fVolume(volume),
	fNode(NULL),
	fName(NULL)
{
}


Index::~Index()
{
	if (fNode == NULL)
		return;

	if (fVolume->ID() >= 0)
		put_vnode(fVolume->FSVolume(), fNode->ID());
}


void
Index::Unset()
{
	if (fNode == NULL)
		return;

	if (fVolume->ID() >= 0)
		put_vnode(fVolume->FSVolume(), fNode->ID());
	fNode = NULL;
	fName = NULL;
}


/*!	Sets the index to specified one. Returns an error if the index could
	not be found or initialized.
	Note, Index::Update() may be called on the object even if this method
	failed previously. In this case, it will only update live queries for
	the updated attribute.
*/
status_t
Index::SetTo(const char* name)
{
	// remove the old node, if the index is set for the second time
	Unset();

	fName = name;
		// only stores the pointer, so it assumes that it will stay constant
		// in further comparisons (currently only used in Index::Update())

	// Note, the name is saved even if the index couldn't be initialized!
	// This is used to optimize Index::Update() in case there is no index

	Inode* indices = fVolume->IndicesNode();
	if (indices == NULL)
		return B_ENTRY_NOT_FOUND;

	InodeReadLocker locker(indices);

	BPlusTree* tree = indices->Tree();
	if (tree == NULL)
		return B_BAD_VALUE;

	ino_t id;
	status_t status = tree->Find((uint8*)name, (uint16)strlen(name), &id);
	if (status != B_OK)
		return status;

	Vnode vnode(fVolume, id);
	if (vnode.Get(&fNode) != B_OK)
		return B_ENTRY_NOT_FOUND;

	if (fNode == NULL) {
		FATAL(("fatal error at Index::InitCheck(), get_vnode() returned "
			"NULL pointer\n"));
		return B_ERROR;
	}

	vnode.Keep();
	return B_OK;
}


/*!	Returns a standard type code for the stat() index type codes. Returns
	zero if the type is not known (can only happen if the mode field is
	corrupted somehow or not that of an index).
*/
uint32
Index::Type()
{
	if (fNode == NULL)
		return 0;

	switch (fNode->Mode() & (S_STR_INDEX | S_INT_INDEX | S_UINT_INDEX
			| S_LONG_LONG_INDEX | S_ULONG_LONG_INDEX | S_FLOAT_INDEX
			| S_DOUBLE_INDEX)) {
		case S_INT_INDEX:
			return B_INT32_TYPE;
		case S_UINT_INDEX:
			return B_UINT32_TYPE;
		case S_LONG_LONG_INDEX:
			return B_INT64_TYPE;
		case S_ULONG_LONG_INDEX:
			return B_UINT64_TYPE;
		case S_FLOAT_INDEX:
			return B_FLOAT_TYPE;
		case S_DOUBLE_INDEX:
			return B_DOUBLE_TYPE;
		case S_STR_INDEX:
			return B_STRING_TYPE;
	}
	FATAL(("index has unknown type!\n"));
	return 0;
}


size_t
Index::KeySize()
{
	if (fNode == NULL)
		return 0;

	int32 mode = fNode->Mode() & (S_STR_INDEX | S_INT_INDEX | S_UINT_INDEX
		| S_LONG_LONG_INDEX | S_ULONG_LONG_INDEX | S_FLOAT_INDEX
		| S_DOUBLE_INDEX);

	if (mode == S_STR_INDEX)
		// string indices don't have a fixed key size
		return 0;

	switch (mode) {
		case S_INT_INDEX:
		case S_UINT_INDEX:
			return sizeof(int32);
		case S_LONG_LONG_INDEX:
		case S_ULONG_LONG_INDEX:
			return sizeof(int64);
		case S_FLOAT_INDEX:
			return sizeof(float);
		case S_DOUBLE_INDEX:
			return sizeof(double);
	}
	FATAL(("index has unknown type!\n"));
	return 0;
}


status_t
Index::Create(Transaction& transaction, const char* name, uint32 type)
{
	Unset();

	int32 mode = 0;
	switch (type) {
		case B_INT32_TYPE:
			mode = S_INT_INDEX;
			break;
		case B_UINT32_TYPE:
			mode = S_UINT_INDEX;
			break;
		case B_INT64_TYPE:
			mode = S_LONG_LONG_INDEX;
			break;
		case B_UINT64_TYPE:
			mode = S_ULONG_LONG_INDEX;
			break;
		case B_FLOAT_TYPE:
			mode = S_FLOAT_INDEX;
			break;
		case B_DOUBLE_TYPE:
			mode = S_DOUBLE_INDEX;
			break;
		case B_STRING_TYPE:
		case B_MIME_STRING_TYPE:
			// B_MIME_STRING_TYPE is the only supported non-standard type, but
			// will be handled like a B_STRING_TYPE internally
			mode = S_STR_INDEX;
			break;
		default:
			return B_BAD_TYPE;
	}

	// do we need to create the index directory first?
	if (fVolume->IndicesNode() == NULL) {
		status_t status = fVolume->CreateIndicesRoot(transaction);
		if (status < B_OK)
			RETURN_ERROR(status);
	}

	// Inode::Create() will keep the inode locked for us
	return Inode::Create(transaction, fVolume->IndicesNode(), name,
		S_INDEX_DIR | S_DIRECTORY | mode, 0, type, NULL, NULL, &fNode);
}


/*!	Updates the specified index, the oldKey will be removed from, the newKey
	inserted into the tree.
	If the method returns B_BAD_INDEX, it means the index couldn't be found -
	the most common reason will be that the index doesn't exist.
	You may not want to let the whole transaction fail because of that.
*/
status_t
Index::Update(Transaction& transaction, const char* name, int32 type,
	const uint8* oldKey, uint16 oldLength, const uint8* newKey,
	uint16 newLength, Inode* inode)
{
	if (name == NULL
		|| (oldKey == NULL && newKey == NULL)
		|| (oldKey != NULL && oldLength == 0)
		|| (newKey != NULL && newLength == 0))
		return B_BAD_VALUE;

	// B_MIME_STRING_TYPE is the only supported non-standard type
	if (type == B_MIME_STRING_TYPE)
		type = B_STRING_TYPE;

	// If the two keys are identical, don't do anything - only compare if the
	// type has been set, until we have a real type code, we can't do much
	// about the comparison here
	if (oldLength == 0) {
		if (newLength == 0)
			return B_OK;
	} else if (newLength != 0 && !QueryParser::compareKeys(type,
			oldKey, oldLength, newKey, newLength)) {
		return B_OK;
	}

	// update all live queries about the change, if they have an index or not
	fVolume->UpdateLiveQueries(inode, name, type, oldKey, oldLength,
		newKey, newLength);

	if (((name != fName || strcmp(name, fName)) && SetTo(name) != B_OK)
		|| fNode == NULL)
		return B_BAD_INDEX;

	BPlusTree* tree = Node()->Tree();
	if (tree == NULL)
		return B_BAD_VALUE;

	// remove the old key from the tree

	Node()->WriteLockInTransaction(transaction);

	status_t status = B_OK;

	if (oldKey != NULL) {
		status = tree->Remove(transaction, (const uint8*)oldKey, oldLength,
			inode->ID());
		if (status == B_ENTRY_NOT_FOUND) {
			// That's not nice, but no reason to let the whole thing fail
			INFORM(("Could not find value in index \"%s\"!\n", name));
		} else if (status != B_OK)
			return status;
	}

	// add the new key to the tree

	if (newKey != NULL) {
		status = tree->Insert(transaction, (const uint8*)newKey, newLength,
			inode->ID());
	}

	RETURN_ERROR(status);
}


status_t
Index::InsertName(Transaction& transaction, const char* name, Inode* inode)
{
	return UpdateName(transaction, NULL, name, inode);
}


status_t
Index::RemoveName(Transaction& transaction, const char* name, Inode* inode)
{
	return UpdateName(transaction, name, NULL, inode);
}


status_t
Index::UpdateName(Transaction& transaction, const char* oldName,
	const char* newName, Inode* inode)
{
	ASSERT(inode->IsRegularNode());

	uint16 oldLength = oldName != NULL ? strlen(oldName) : 0;
	uint16 newLength = newName != NULL ? strlen(newName) : 0;
	return Update(transaction, "name", B_STRING_TYPE, (uint8*)oldName,
		oldLength, (uint8*)newName, newLength, inode);
}


status_t
Index::InsertSize(Transaction& transaction, Inode* inode)
{
	ASSERT(inode->InSizeIndex());

	off_t size = inode->Size();
	return Update(transaction, "size", B_INT64_TYPE, NULL, 0, (uint8*)&size,
		sizeof(int64), inode);
}


status_t
Index::RemoveSize(Transaction& transaction, Inode* inode)
{
	ASSERT(inode->InSizeIndex());

	// Inode::OldSize() is the size that's in the index
	off_t size = inode->OldSize();
	return Update(transaction, "size", B_INT64_TYPE, (uint8*)&size,
		sizeof(int64), NULL, 0, inode);
}


status_t
Index::UpdateSize(Transaction& transaction, Inode* inode)
{
	ASSERT(inode->InSizeIndex());

	off_t oldSize = inode->OldSize();
	off_t newSize = inode->Size();

	status_t status = Update(transaction, "size", B_INT64_TYPE,
		(uint8*)&oldSize, sizeof(int64), (uint8*)&newSize, sizeof(int64),
		inode);
	if (status == B_OK)
		inode->UpdateOldSize();

	return status;
}


status_t
Index::InsertLastModified(Transaction& transaction, Inode* inode)
{
	ASSERT(inode->InLastModifiedIndex());

	off_t modified = inode->LastModified();
	return Update(transaction, "last_modified", B_INT64_TYPE, NULL, 0,
		(uint8*)&modified, sizeof(int64), inode);
}


status_t
Index::RemoveLastModified(Transaction& transaction, Inode* inode)
{
	ASSERT(inode->InLastModifiedIndex());

	// Inode::OldLastModified() is the value which is in the index
	off_t modified = inode->OldLastModified();
	return Update(transaction, "last_modified", B_INT64_TYPE,
		(uint8*)&modified, sizeof(int64), NULL, 0, inode);
}


status_t
Index::UpdateLastModified(Transaction& transaction, Inode* inode,
	bigtime_t modified)
{
	ASSERT(inode->InLastModifiedIndex());

	bigtime_t oldModified = inode->OldLastModified();
	if (modified == -1)
		modified = bfs_inode::ToInode(real_time_clock_usecs());

	status_t status = Update(transaction, "last_modified", B_INT64_TYPE,
		(uint8*)&oldModified, sizeof(int64), (uint8*)&modified,
		sizeof(int64), inode);

	inode->Node().last_modified_time = HOST_ENDIAN_TO_BFS_INT64(modified);
	// No matter if the index exists or not, we will update the old last
	// modified field, since this is also being used to determine whether
	// or not to send out notifications.
	if (status == B_OK || status == B_BAD_INDEX)
		inode->UpdateOldLastModified();

	return status;
}