#include "cache.h"
#include "shared/util.h"
#include "shared/log.h" // only LOG_DEBUG
#include "error.h"
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <errno.h>
#include <assert.h>
int pt_cache_new (struct pt_cache **cache_ptr, const char *path, int mode)
{
struct pt_cache *cache;
int err;
// alloc
if ((cache = calloc(1, sizeof(*cache))) == NULL)
RETURN_ERROR(PT_ERR_MEM);
if ((cache->path = strdup(path)) == NULL)
JUMP_SET_ERROR(err, PT_ERR_MEM);
// init
cache->fd = -1;
cache->mode = mode;
// ok
*cache_ptr = cache;
return 0;
error:
// cleanup
if (cache)
pt_cache_destroy(cache);
return err;
}
int pt_cache_status (struct pt_cache *cache, const char *img_path)
{
struct stat st_img, st_cache;
// test original file
if (stat(img_path, &st_img) < 0)
RETURN_ERROR(PT_ERR_IMG_STAT);
// test cache file
if (stat(cache->path, &st_cache) < 0) {
// always stale if it doesn't exist yet
if (errno == ENOENT)
return PT_CACHE_NONE;
else
RETURN_ERROR(PT_ERR_CACHE_STAT);
}
// compare mtime
if (st_img.st_mtime > st_cache.st_mtime)
return PT_CACHE_STALE;
else
return PT_CACHE_FRESH;
}
int pt_cache_info (struct pt_cache *cache, struct pt_image_info *info)
{
struct stat st;
int err;
// ensure open
if ((err = pt_cache_open(cache)))
return err;
info->width = cache->header->width;
info->height = cache->header->height;
// stat
if (stat(cache->path, &st) < 0) {
// unknown
info->cache_mtime = 0;
info->cache_bytes = 0;
info->cache_blocks = 0;
} else {
// store
info->cache_mtime = st.st_mtime;
info->cache_bytes = st.st_size;
info->cache_blocks = st.st_blocks;
}
return 0;
}
/**
* Abort any incomplete open operation, cleaning up
*/
static void pt_cache_abort (struct pt_cache *cache)
{
if (cache->header != NULL) {
munmap(cache->header, PT_CACHE_HEADER_SIZE + cache->size);
cache->header = NULL;
cache->data = NULL;
}
if (cache->fd >= 0) {
close(cache->fd);
cache->fd = -1;
}
}
/**
* Open the cache file as an fd for reading
*
* XXX: needs locking
*/
static int pt_cache_open_read_fd (struct pt_cache *cache, int *fd_ptr)
{
int fd;
// actual open()
if ((fd = open(cache->path, O_RDONLY)) < 0)
RETURN_ERROR_ERRNO(PT_ERR_OPEN_MODE, EACCES);
// ok
*fd_ptr = fd;
return 0;
}
/**
* Open the .tmp cache file as an fd for writing
*/
static int pt_cache_open_tmp_fd (struct pt_cache *cache, int *fd_ptr)
{
int fd;
char tmp_path[1024];
// get .tmp path
if (path_with_fext(cache->path, tmp_path, sizeof(tmp_path), ".tmp"))
RETURN_ERROR(PT_ERR_PATH);
// open for write, create
// XXX: locking?
if ((fd = open(tmp_path, O_RDWR | O_CREAT, 0644)) < 0)
RETURN_ERROR(PT_ERR_CACHE_OPEN_TMP);
// ok
*fd_ptr = fd;
return 0;
}
/**
* Mmap the opened cache file using PT_CACHE_HEADER_SIZE plus the calculated size stored in cache->size
*/
static int pt_cache_open_mmap (struct pt_cache *cache, void **addr_ptr, bool readonly)
{
int prot = 0;
void *addr;
// determine prot
prot |= PROT_READ;
if (!readonly) {
assert(cache->mode & PT_OPEN_UPDATE);
prot |= PROT_WRITE;
}
// mmap() the full file including header
if ((addr = mmap(NULL, PT_CACHE_HEADER_SIZE + cache->size, prot, MAP_SHARED, cache->fd, 0)) == MAP_FAILED)
RETURN_ERROR(PT_ERR_CACHE_MMAP);
// ok
*addr_ptr = addr;
return 0;
}
/**
* Read in the cache header from the open file
*/
static int pt_cache_read_header (struct pt_cache *cache, struct pt_cache_header *header)
{
size_t len = sizeof(*header);
char *buf = (char *) header;
// seek to start
if (lseek(cache->fd, 0, SEEK_SET) != 0)
RETURN_ERROR(PT_ERR_CACHE_SEEK);
// write out full header
while (len) {
ssize_t ret;
// try and write out the header
if ((ret = read(cache->fd, buf, len)) <= 0)
RETURN_ERROR(PT_ERR_CACHE_READ);
// update offset
buf += ret;
len -= ret;
}
// done
return 0;
}
/**
* Write out the cache header into the opened file
*/
static int pt_cache_write_header (struct pt_cache *cache, const struct pt_cache_header *header)
{
size_t len = sizeof(*header);
const char *buf = (const char *) header;
// seek to start
if (lseek(cache->fd, 0, SEEK_SET) != 0)
RETURN_ERROR(PT_ERR_CACHE_SEEK);
// write out full header
while (len) {
ssize_t ret;
// try and write out the header
if ((ret = write(cache->fd, buf, len)) <= 0)
RETURN_ERROR(PT_ERR_CACHE_WRITE);
// update offset
buf += ret;
len -= ret;
}
// done
return 0;
}
/**
* Create a new .tmp cache file, open it, and write out the header.
*/
static int pt_cache_create (struct pt_cache *cache, struct pt_cache_header *header)
{
void *base;
int err;
// no access
if (!(cache->mode & PT_OPEN_UPDATE))
RETURN_ERROR(PT_ERR_OPEN_MODE);
// open as .tmp
if ((err = pt_cache_open_tmp_fd(cache, &cache->fd)))
return err;
// calculate data size
cache->size = header->height * header->row_bytes;
// grow file
if (ftruncate(cache->fd, PT_CACHE_HEADER_SIZE + cache->size) < 0)
JUMP_SET_ERROR(err, PT_ERR_CACHE_TRUNC);
// mmap header and data
if ((err = pt_cache_open_mmap(cache, &base, false)))
JUMP_ERROR(err);
cache->header = base;
cache->data = base + PT_CACHE_HEADER_SIZE;
// write header
// XXX: should just mmap...
if ((err = pt_cache_write_header(cache, header)))
JUMP_ERROR(err);
// done
return 0;
error:
// cleanup
pt_cache_abort(cache);
return err;
}
/**
* Rename the opened .tmp to .cache
*/
static int pt_cache_create_done (struct pt_cache *cache)
{
char tmp_path[1024];
// get .tmp path
if (path_with_fext(cache->path, tmp_path, sizeof(tmp_path), ".tmp"))
RETURN_ERROR(PT_ERR_PATH);
// rename
if (rename(tmp_path, cache->path) < 0)
RETURN_ERROR(PT_ERR_CACHE_RENAME_TMP);
// ok
return 0;
}
int pt_cache_open (struct pt_cache *cache)
{
struct pt_cache_header header;
void *base;
int err;
// ignore if already open
if (cache->header && cache->data)
return 0;
// open the .cache
if ((err = pt_cache_open_read_fd(cache, &cache->fd)))
return err;
// read in header
if ((err = pt_cache_read_header(cache, &header)))
JUMP_ERROR(err);
// calculate data size
cache->size = header.height * header.row_bytes;
// mmap header and data
if ((err = pt_cache_open_mmap(cache, &base, true)))
JUMP_ERROR(err);
cache->header = base;
cache->data = base + PT_CACHE_HEADER_SIZE;
// done
return 0;
error:
// cleanup
pt_cache_abort(cache);
return err;
}
#define min(a, b) (((a) < (b)) ? (a) : (b))
/**
* Decode the PNG data directly to mmap() - not good for sparse backgrounds
*/
static int decode_png_raw (struct pt_cache *cache, png_structp png, png_infop info)
{
// write out raw image data a row at a time
for (size_t row = 0; row < cache->header->height; row++) {
// read row data, non-interlaced
png_read_row(png, cache->data + row * cache->header->row_bytes, NULL);
}
return 0;
}
static int decode_png_sparse (struct pt_cache *cache, png_structp png, png_infop info)
{
// one row of pixel data
uint8_t *row_buf;
// alloc
if ((row_buf = malloc(cache->header->row_bytes)) == NULL)
RETURN_ERROR(PT_ERR_MEM);
// decode each row at a time
for (size_t row = 0; row < cache->header->height; row++) {
// read row data, non-interlaced
png_read_row(png, row_buf, NULL);
// skip background-colored regions to keep the cache file sparse
// ...in blocks of PT_CACHE_BLOCK_SIZE bytes
for (size_t col_base = 0; col_base < cache->header->width; col_base += PT_CACHE_BLOCK_SIZE) {
// size of this block in bytes
size_t block_size = min(PT_CACHE_BLOCK_SIZE * cache->header->col_bytes, cache->header->row_bytes - col_base);
// ...each pixel
for (
size_t col = col_base;
// BLOCK_SIZE * col_bytes wide, don't go over the edge
col < col_base + block_size;
col += cache->header->col_bytes
) {
// test this pixel
if (bcmp(row_buf + col, cache->header->params.background_color, cache->header->col_bytes)) {
// differs
memcpy(
cache->data + row * cache->header->row_bytes + col_base,
row_buf + col_base,
block_size
);
// skip to next block
break;
}
}
// skip this block
continue;
}
}
return 0;
}
int pt_cache_update_png (struct pt_cache *cache, png_structp png, png_infop info, const struct pt_image_params *params)
{
struct pt_cache_header header;
int err;
// XXX: check cache_mode
// XXX: check image doesn't use any options we don't handle
// XXX: close any already-opened cache file
memset(&header, 0, sizeof(header));
// fill in basic info
header.width = png_get_image_width(png, info);
header.height = png_get_image_height(png, info);
header.bit_depth = png_get_bit_depth(png, info);
header.color_type = png_get_color_type(png, info);
log_debug("width=%u, height=%u, bit_depth=%u, color_type=%u",
header.width, header.height, header.bit_depth, header.color_type
);
// only pack 1 pixel per byte, changes rowbytes
if (header.bit_depth < 8)
png_set_packing(png);
// fill in other info
header.row_bytes = png_get_rowbytes(png, info);
// calculate bpp as num_channels * bpc
// XXX: this assumes the packed bit depth will be either 8 or 16
header.col_bytes = png_get_channels(png, info) * (header.bit_depth == 16 ? 2 : 1);
log_debug("row_bytes=%u, col_bytes=%u", header.row_bytes, header.col_bytes);
// palette etc.
if (header.color_type == PNG_COLOR_TYPE_PALETTE) {
int num_palette;
png_colorp palette;
if (png_get_PLTE(png, info, &palette, &num_palette) == 0)
// XXX: PLTE chunk not read?
RETURN_ERROR(PT_ERR_PNG);
// should only be 256 of them at most
assert(num_palette <= PNG_MAX_PALETTE_LENGTH);
// copy
header.num_palette = num_palette;
memcpy(&header.palette, palette, num_palette * sizeof(*palette));
log_debug("num_palette=%u", num_palette);
}
// any params
if (params)
header.params = *params;
// create .tmp and write out header
if ((err = pt_cache_create(cache, &header)))
return err;
// decode
if ((err = decode_png_sparse(cache, png, info)))
return err;
// move from .tmp to .cache
if ((err = pt_cache_create_done(cache)))
// XXX: pt_cache_abort?
return err;
// done!
return 0;
}
/**
* Return a pointer to the pixel data on \a row, starting at \a col.
*/
static inline void* tile_row_col (struct pt_cache *cache, size_t row, size_t col)
{
return cache->data + (row * cache->header->row_bytes) + (col * cache->header->col_bytes);
}
/**
* Fill in a clipped region of \a width_px pixels at the given row segment
*/
static inline void tile_row_fill_clip (struct pt_cache *cache, png_byte *row, size_t width_px)
{
// XXX: use a configureable background color, or full transparency?
memset(row, /* 0xd7 */ 0x00, width_px * cache->header->col_bytes);
}
/**
* Write raw tile image data, directly from the cache
*/
static int write_png_data_direct (struct pt_cache *cache, png_structp png, png_infop info, const struct pt_tile_info *ti)
{
for (size_t row = ti->y; row < ti->y + ti->height; row++)
// write data directly
png_write_row(png, tile_row_col(cache, row, ti->x));
return 0;
}
/**
* Write clipped tile image data (a tile that goes over the edge of the actual image) by aligning the data from the cache as needed
*/
static int write_png_data_clipped (struct pt_cache *cache, png_structp png, png_infop info, const struct pt_tile_info *ti)
{
png_byte *rowbuf;
size_t row;
// image data goes from (ti->x ... clip_x, ti->y ... clip_y), remaining region is filled
size_t clip_x, clip_y;
// figure out if the tile clips over the right edge
// XXX: use min()
if (ti->x + ti->width > cache->header->width)
clip_x = cache->header->width;
else
clip_x = ti->x + ti->width;
// figure out if the tile clips over the bottom edge
// XXX: use min()
if (ti->y + ti->height > cache->header->height)
clip_y = cache->header->height;
else
clip_y = ti->y + ti->height;
// allocate buffer for a single row of image data
if ((rowbuf = malloc(ti->width * cache->header->col_bytes)) == NULL)
RETURN_ERROR(PT_ERR_MEM);
// how much data we actually have for each row, in px and bytes
// from [(tile x)---](clip x)
size_t row_px = clip_x - ti->x;
size_t row_bytes = row_px * cache->header->col_bytes;
// write the rows that we have
// from [(tile y]---](clip y)
for (row = ti->y; row < clip_y; row++) {
// copy in the actual tile data...
memcpy(rowbuf, tile_row_col(cache, row, ti->x), row_bytes);
// generate the data for the remaining, clipped, columns
tile_row_fill_clip(cache, rowbuf + row_bytes, (ti->width - row_px));
// write
png_write_row(png, rowbuf);
}
// generate the data for the remaining, clipped, rows
tile_row_fill_clip(cache, rowbuf, ti->width);
// write out the remaining rows as clipped data
for (; row < ti->y + ti->height; row++)
png_write_row(png, rowbuf);
// ok
return 0;
}
static size_t scale_by_zoom_factor (size_t value, int z)
{
if (z > 0)
return value << z;
else if (z < 0)
return value >> -z;
else
return value;
}
#define ADD_AVG(l, r) (l) = ((l) + (r)) / 2
static int png_pixel_data (png_color *out, struct pt_cache *cache, size_t row, size_t col)
{
if (cache->header->color_type == PNG_COLOR_TYPE_PALETTE) {
// palette entry number
int p;
if (cache->header->bit_depth == 8)
p = *((uint8_t *) tile_row_col(cache, row, col));
else
return -1;
if (p >= cache->header->num_palette)
return -1;
// reference data from palette
*out = cache->header->palette[p];
return 0;
} else {
return -1;
}
}
/**
* Write unscaled tile data
*/
static int write_png_data_unzoomed (struct pt_cache *cache, png_structp png, png_infop info, const struct pt_tile_info *ti)
{
int err;
// set basic info
png_set_IHDR(png, info, ti->width, ti->height, cache->header->bit_depth, cache->header->color_type,
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT
);
// set palette?
if (cache->header->color_type == PNG_COLOR_TYPE_PALETTE)
png_set_PLTE(png, info, cache->header->palette, cache->header->num_palette);
// write meta-info
png_write_info(png, info);
// our pixel data is packed into 1 pixel per byte (8bpp or 16bpp)
png_set_packing(png);
// figure out if the tile clips
if (ti->x + ti->width <= cache->header->width && ti->y + ti->height <= cache->header->height)
// doesn't clip, just use the raw data
err = write_png_data_direct(cache, png, info, ti);
else
// fill in clipped regions
err = write_png_data_clipped(cache, png, info, ti);
return err;
}
/**
* Write scaled tile data
*/
static int write_png_data_zoomed (struct pt_cache *cache, png_structp png, png_infop info, const struct pt_tile_info *ti)
{
// size of the image data in px
size_t data_width = scale_by_zoom_factor(ti->width, -ti->zoom);
size_t data_height = scale_by_zoom_factor(ti->height, -ti->zoom);
// input pixels per output pixel
size_t pixel_size = scale_by_zoom_factor(1, -ti->zoom);
// bytes per output pixel
size_t pixel_bytes = 3;
// size of the output tile in px
size_t row_width = ti->width;
// size of an output row in bytes (RGB)
size_t row_bytes = row_width * 3;
// buffer to hold output rows
uint8_t *row_buf;
// XXX: only supports zooming out...
if (ti->zoom >= 0)
RETURN_ERROR(PT_ERR_ZOOM);
if ((row_buf = malloc(row_bytes)) == NULL)
RETURN_ERROR(PT_ERR_MEM);
// define pixel format: 8bpp RGB
png_set_IHDR(png, info, ti->width, ti->height, 8, PNG_COLOR_TYPE_RGB,
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT
);
// write meta-info
png_write_info(png, info);
// ...each output row
for (size_t out_row = 0; out_row < ti->height; out_row++) {
memset(row_buf, 0, row_bytes);
// ...includes pixels starting from this row.
size_t in_row_offset = ti->y + scale_by_zoom_factor(out_row, -ti->zoom);
// ...each out row includes pixel_size in rows
for (size_t in_row = in_row_offset; in_row < in_row_offset + pixel_size && in_row < cache->header->height; in_row++) {
// and includes each input pixel
for (size_t in_col = ti->x; in_col < ti->x + data_width && in_col < cache->header->width; in_col++) {
png_color c;
// ...for this output pixel
size_t out_col = scale_by_zoom_factor(in_col - ti->x, ti->zoom);
// get pixel RGB data
if (png_pixel_data(&c, cache, in_row, in_col))
return -1;
// average the RGB data
ADD_AVG(row_buf[out_col * pixel_bytes + 0], c.red);
ADD_AVG(row_buf[out_col * pixel_bytes + 1], c.green);
ADD_AVG(row_buf[out_col * pixel_bytes + 2], c.blue);
}
}
// output
png_write_row(png, row_buf);
}
// done
return 0;
}
int pt_cache_tile_png (struct pt_cache *cache, png_structp png, png_infop info, const struct pt_tile_info *ti)
{
int err;
// ensure open
if ((err = pt_cache_open(cache)))
return err;
// check within bounds
if (ti->x >= cache->header->width || ti->y >= cache->header->height)
// completely outside
RETURN_ERROR(PT_ERR_TILE_CLIP);
// unscaled or scaled?
if (ti->zoom)
err = write_png_data_zoomed(cache, png, info, ti);
else
err = write_png_data_unzoomed(cache, png, info, ti);
if (err)
return err;
// done, flush remaining output
png_write_flush(png);
// ok
return 0;
}
void pt_cache_destroy (struct pt_cache *cache)
{
free(cache->path);
pt_cache_abort(cache);
free(cache);
}