/* SPDX-License-Identifier: LGPL-3.0-or-later */
/*
 * common.c
 *
 * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
 */
#define SQFS_BUILDING_DLL
#include "internal.h"

static int set_block_size(sqfs_inode_generic_t **inode,
			  sqfs_u32 index, sqfs_u32 size)
{
	size_t min_size = (index + 1) * sizeof(sqfs_u32);
	size_t avail = (*inode)->payload_bytes_available;
	sqfs_inode_generic_t *new;
	size_t newsz;

	if (avail < min_size) {
		newsz = avail ? avail : (sizeof(sqfs_u32) * 4);
		while (newsz < min_size)
			newsz *= 2;

		if (SZ_ADD_OV(newsz, sizeof(**inode), &newsz))
			return SQFS_ERROR_OVERFLOW;

		if (sizeof(size_t) > sizeof(sqfs_u32)) {
			if ((newsz - sizeof(**inode)) > 0x0FFFFFFFFUL)
				return SQFS_ERROR_OVERFLOW;
		}

		new = realloc((*inode), newsz);
		if (new == NULL)
			return SQFS_ERROR_ALLOC;

		(*inode) = new;
		(*inode)->payload_bytes_available = newsz - sizeof(**inode);
	}

	(*inode)->extra[index] = size;

	if (min_size >= (*inode)->payload_bytes_used)
		(*inode)->payload_bytes_used = min_size;

	return 0;
}

static void release_old_block(sqfs_block_processor_t *proc, sqfs_block_t *blk)
{
	blk->next = proc->free_list;
	proc->free_list = blk;
}

int process_completed_block(sqfs_block_processor_t *proc, sqfs_block_t *blk)
{
	sqfs_u64 location;
	sqfs_u32 size;
	int err;

	err = proc->wr->write_data_block(proc->wr, blk->user, blk->size,
					 blk->checksum,
					 blk->flags & ~BLK_FLAG_INTERNAL,
					 blk->data, &location);
	if (err)
		goto out;

	proc->stats.output_bytes_generated += blk->size;

	if (blk->flags & SQFS_BLK_IS_SPARSE) {
		if (blk->inode != NULL) {
			sqfs_inode_make_extended(*(blk->inode));
			(*(blk->inode))->data.file_ext.sparse += blk->size;

			err = set_block_size(blk->inode, blk->index, 0);
			if (err)
				goto out;
		}
		proc->stats.sparse_block_count += 1;
	} else if (blk->size != 0) {
		size = blk->size;
		if (!(blk->flags & SQFS_BLK_IS_COMPRESSED))
			size |= 1 << 24;

		if (blk->flags & SQFS_BLK_FRAGMENT_BLOCK) {
			if (proc->frag_tbl != NULL) {
				err = sqfs_frag_table_set(proc->frag_tbl,
							  blk->index, location,
							  size);
				if (err)
					goto out;
			}
			proc->stats.frag_block_count += 1;
		} else {
			if (blk->inode != NULL) {
				err = set_block_size(blk->inode, blk->index,
						     size);
				if (err)
					goto out;
			}
			proc->stats.data_block_count += 1;
		}
	}

	if (blk->flags & SQFS_BLK_LAST_BLOCK && blk->inode != NULL)
		sqfs_inode_set_file_block_start(*(blk->inode), location);
out:
	release_old_block(proc, blk);
	return err;
}

static bool is_zero_block(unsigned char *ptr, size_t size)
{
	return ptr[0] == 0 && memcmp(ptr, ptr + 1, size - 1) == 0;
}

static int process_block(void *userptr, void *workitem)
{
	sqfs_compressor_t *cmp = ((worker_data_t *)userptr)->cmp;
	sqfs_u8 *scratch = ((worker_data_t *)userptr)->scratch;
	size_t scratch_size = ((worker_data_t *)userptr)->scratch_size;
	sqfs_block_t *block = workitem;
	sqfs_s32 ret;

	if (block->size == 0)
		return 0;

	if (!(block->flags & SQFS_BLK_IGNORE_SPARSE) &&
	    is_zero_block(block->data, block->size)) {
		block->flags |= SQFS_BLK_IS_SPARSE;
		return 0;
	}

	if (block->flags & SQFS_BLK_DONT_HASH) {
		block->checksum = 0;
	} else {
		block->checksum = xxh32(block->data, block->size);
	}

	if (block->flags & (SQFS_BLK_IS_FRAGMENT | SQFS_BLK_DONT_COMPRESS))
		return 0;

	ret = cmp->do_block(cmp, block->data, block->size,
			    scratch, scratch_size);
	if (ret < 0)
		return ret;

	if (ret > 0) {
		memcpy(block->data, scratch, ret);
		block->size = ret;
		block->flags |= SQFS_BLK_IS_COMPRESSED;
	}
	return 0;
}

int process_completed_fragment(sqfs_block_processor_t *proc,
			       sqfs_block_t *frag,
			       sqfs_block_t **blk_out)
{
	chunk_info_t *chunk, search;
	struct hash_entry *entry;
	sqfs_u32 index, offset;
	size_t size;
	int err;

	if (frag->flags & SQFS_BLK_IS_SPARSE) {
		if (frag->inode != NULL) {
			sqfs_inode_make_extended(*(frag->inode));
			set_block_size(frag->inode, frag->index, 0);
			(*(frag->inode))->data.file_ext.sparse += frag->size;
		}
		proc->stats.sparse_block_count += 1;
		release_old_block(proc, frag);
		return 0;
	}

	proc->stats.total_frag_count += 1;

	if (!(frag->flags & SQFS_BLK_DONT_DEDUPLICATE)) {
		search.hash = frag->checksum;
		search.size = frag->size;

		entry = hash_table_search_pre_hashed(proc->frag_ht,
						     search.hash, &search);

		if (entry != NULL) {
			if (frag->inode != NULL) {
				chunk = entry->data;
				sqfs_inode_set_frag_location(*(frag->inode),
							     chunk->index,
							     chunk->offset);
			}
			release_old_block(proc, frag);
			return 0;
		}
	}

	if (proc->frag_block != NULL) {
		size = proc->frag_block->size + frag->size;

		if (size > proc->max_block_size) {
			*blk_out = proc->frag_block;
			proc->frag_block = NULL;
		}
	}

	if (proc->frag_block == NULL) {
		if (proc->frag_tbl == NULL) {
			index = 0;
		} else {
			err = sqfs_frag_table_append(proc->frag_tbl,
						     0, 0, &index);
			if (err)
				goto fail;
		}

		offset = 0;
		proc->frag_block = frag;
		proc->frag_block->index = index;
		proc->frag_block->flags &= SQFS_BLK_DONT_COMPRESS;
		proc->frag_block->flags |= SQFS_BLK_FRAGMENT_BLOCK;
	} else {
		index = proc->frag_block->index;
		offset = proc->frag_block->size;

		memcpy(proc->frag_block->data + proc->frag_block->size,
		       frag->data, frag->size);

		proc->frag_block->size += frag->size;
		proc->frag_block->flags |=
			(frag->flags & SQFS_BLK_DONT_COMPRESS);
		release_old_block(proc, frag);
	}

	if (proc->frag_tbl != NULL) {
		err = SQFS_ERROR_ALLOC;
		chunk = calloc(1, sizeof(*chunk));
		if (chunk == NULL)
			goto fail_outblk;

		chunk->index = index;
		chunk->offset = offset;
		chunk->size = frag->size;
		chunk->hash = frag->checksum;

		entry = hash_table_insert_pre_hashed(proc->frag_ht, chunk->hash,
						     chunk, chunk);

		if (entry == NULL) {
			free(chunk);
			goto fail_outblk;
		}
	}

	if (frag->inode != NULL)
		sqfs_inode_set_frag_location(*(frag->inode), index, offset);

	proc->stats.actual_frag_count += 1;
	return 0;
fail:
	release_old_block(proc, frag);
fail_outblk:
	if (*blk_out != NULL) {
		release_old_block(proc, *blk_out);
		*blk_out = NULL;
	}
	return err;
}

static uint32_t chunk_info_hash(void *user, const void *key)
{
	const chunk_info_t *chunk = key;
	(void)user;
	return chunk->hash;
}

static bool chunk_info_equals(void *user, const void *k, const void *c)
{
	const chunk_info_t *key = k, *cmp = c;
	(void)user;
	return key->size == cmp->size && key->hash == cmp->hash;
}

static void ht_delete_function(struct hash_entry *entry)
{
	free(entry->data);
}

static void block_processor_destroy(sqfs_object_t *base)
{
	sqfs_block_processor_t *proc = (sqfs_block_processor_t *)base;
	sqfs_block_t *it;

	if (proc->frag_block != NULL)
		release_old_block(proc, proc->frag_block);

	free(proc->blk_current);

	while (proc->free_list != NULL) {
		it = proc->free_list;
		proc->free_list = it->next;
		free(it);
	}

	hash_table_destroy(proc->frag_ht, ht_delete_function);

	/* XXX: shut down the pool first before cleaning up the worker data */
	proc->pool->destroy(proc->pool);

	while (proc->workers != NULL) {
		worker_data_t *worker = proc->workers;
		proc->workers = worker->next;

		sqfs_destroy(worker->cmp);
		free(worker);
	}

	free(proc);
}

int sqfs_block_processor_create_ex(const sqfs_block_processor_desc_t *desc,
				   sqfs_block_processor_t **out)
{
	sqfs_block_processor_t *proc;
	size_t i, count;
	int ret;

	if (desc->size != sizeof(sqfs_block_processor_desc_t))
		return SQFS_ERROR_ARG_INVALID;

	proc = calloc(1, sizeof(*proc));
	if (proc == NULL)
		return SQFS_ERROR_ALLOC;

	proc->max_backlog = desc->max_backlog;
	proc->max_block_size = desc->max_block_size;
	proc->frag_tbl = desc->tbl;
	proc->wr = desc->wr;
	proc->file = desc->file;
	proc->uncmp = desc->uncmp;
	proc->stats.size = sizeof(proc->stats);
	((sqfs_object_t *)proc)->destroy = block_processor_destroy;

	/* create the thread pool */
	proc->pool = thread_pool_create(desc->num_workers, process_block);
	if (proc->pool == NULL) {
		free(proc);
		return SQFS_ERROR_INTERNAL;
	}

	/* create the worker compressors & scratch buffer */
	count = proc->pool->get_worker_count(proc->pool);

	for (i = 0; i < count; ++i) {
		worker_data_t *worker = alloc_flex(sizeof(*worker), 1,
						   desc->max_block_size);
		if (worker == NULL) {
			ret = SQFS_ERROR_ALLOC;
			goto fail_pool;
		}

		worker->scratch_size = desc->max_block_size;
		worker->next = proc->workers;
		proc->workers = worker;

		worker->cmp = sqfs_copy(desc->cmp);
		if (worker->cmp == NULL) {
			ret = SQFS_ERROR_ALLOC;
			goto fail_pool;
		}

		proc->pool->set_worker_ptr(proc->pool, i, worker);
	}

	/* create the fragment hash table */
	proc->frag_ht = hash_table_create(chunk_info_hash, chunk_info_equals);
	if (proc->frag_ht == NULL) {
		ret = SQFS_ERROR_ALLOC;
		goto fail_pool;
	}

	proc->frag_ht->user = proc;
	*out = proc;
	return 0;
fail_pool:
	proc->pool->destroy(proc->pool);
	while (proc->workers != NULL) {
		worker_data_t *worker = proc->workers;
		proc->workers = worker->next;

		if (worker->cmp != NULL)
			sqfs_destroy(worker->cmp);

		free(worker);
	}
	free(proc);
	return ret;
}

sqfs_block_processor_t *sqfs_block_processor_create(size_t max_block_size,
						    sqfs_compressor_t *cmp,
						    unsigned int num_workers,
						    size_t max_backlog,
						    sqfs_block_writer_t *wr,
						    sqfs_frag_table_t *tbl)
{
	sqfs_block_processor_desc_t desc;
	sqfs_block_processor_t *out;

	memset(&desc, 0, sizeof(desc));
	desc.size = sizeof(desc);
	desc.max_block_size = max_block_size;
	desc.num_workers = num_workers;
	desc.max_backlog = max_backlog;
	desc.cmp = cmp;
	desc.wr = wr;
	desc.tbl = tbl;

	if (sqfs_block_processor_create_ex(&desc, &out) != 0)
		return NULL;

	return out;
}