commit 9f8eb874348c84dca1f0cae315a8a3733931d09e
parent d314de4d5c0b8b597358611568784451b07b1d53
Author: Wilson Gheen <wilson@wilsonrgheen.com>
Date: Mon, 9 Jan 2023 16:50:05 -0600
Switch to buffering cache file instead of writing it in place
Diffstat:
| M | photomosaics.c | | | 197 | ++++++++++++++++++++++++++++++++++++++++++++----------------------------------- |
1 file changed, 111 insertions(+), 86 deletions(-)
diff --git a/photomosaics.c b/photomosaics.c
@@ -25,8 +25,9 @@ typedef enum { L, UL, XU, XUL, F } NUM_TYPES;
#define IMG_LIST_MAX_SIZE 5091
static const char *cache_filename = "/home/wilson/.cache/photomosaics/avgs";
-static FILE *cache = NULL;
-static long cache_size = 0;
+static char *cache_buf = NULL;
+static size_t cache_max_size;
+static ssize_t cache_size = 0;
static time_t cache_mtime;
static long *deletables;
static size_t deletables_ind = 0;
@@ -39,6 +40,10 @@ static size_t slen(const char *s, size_t maxlen) {
char *pos = memchr(s, '\0', maxlen);
return pos ? (size_t)(pos - s) : maxlen;
}
+static size_t indof(const char *s, char ch, size_t maxlen) {
+ char *pos = memchr(s, ch, maxlen);
+ return pos ? (size_t)(pos - s) : maxlen;
+}
static bool parse_num(const char *str, NUM_TYPES type, void *out) {
char *endptr;
@@ -90,7 +95,7 @@ static bool parse_ulong(char *str, unsigned long *out) {
return parse_num(str, UL, out);
}
-static Pixel hexstr_top(char *hs) {
+static Pixel hexstr_top(const char *hs) {
char rstr[3] = {hs[0], hs[1],};
char gstr[3] = {hs[2], hs[3],};
char bstr[3] = {hs[4], hs[5],};
@@ -101,76 +106,118 @@ static Pixel hexstr_top(char *hs) {
return p;
}
-static long cache_grep(char *key) {
- if(cache_size < 0)
+static ssize_t cache_grep(char *key) {
+ if(cache_size == -1)
return -1;
- if(!cache) {
+ if(!cache_buf) {
/* init cache */
- cache = fopen(cache_filename, "a+");
- struct stat tmp_st;
- if((!cache) || stat(cache_filename, &tmp_st)) {
- WARN("Couldn't open cache file '%s'. Please ensure the directory exists. Will stop attempting to cache for the remainder of execution.", cache_filename);
+ errno = 0;
+ FILE *cache_file = fopen(cache_filename, "r");
+ struct stat cache_st;
+ if(!cache_file) {
+ WARN("Couldn't open cache file '%s'. "
+ "Please ensure the directory exists.", cache_filename);
+ perror("fopen");
+ }
+ else {
+ if(stat(cache_filename, &cache_st) && errno == ENOENT) {
+ /* stat failed; create the file and try again just in case */
+ errno = 0;
+ FILE *tmp_cache_file = fopen(cache_filename, "a");
+ if(!tmp_cache_file) {
+ WARN("Couldn't open cache file '%s'. "
+ "Please ensure the directory exists.", cache_filename);
+ perror("fopen");
+ }
+ else {
+ assert(!fclose(tmp_cache_file));
+ if(stat(cache_filename, &cache_st)) {
+ WARN("Could not stat cache file '%s'", cache_filename);
+ perror("stat");
+ }
+ }
+ }
+ }
+ if(errno) {
+ WARN("Will stop attempting to cache to %s for the remainder of execution.", cache_filename);
cache_size = -1;
return -1;
}
- cache_mtime = tmp_st.st_mtime;
- fseek(cache, 0, SEEK_END);
- cache_size = ftell(cache);
- /* Just a guess, will realloc later if needed */
+
+ /* No errors, proceed to populate cache_buf */
+
+ cache_mtime = cache_st.st_mtime;
+ long cache_file_size = cache_st.st_size;
+ /* The following 2 mallocs are guesses; will realloc later if needed */
+ cache_max_size = (cache_file_size < 5822 ? 5822 : cache_file_size) + 5 * MAX_FN_LEN;
+ cache_buf = malloc(cache_max_size);
+ cache_buf[0] = 0; /* For the initial strncat later */
deletables = malloc(50 * sizeof(long));
+ cache_size = fread(cache_buf, 1, cache_file_size, cache_file);
+ assert(cache_size == cache_file_size);
+ assert(!fclose(cache_file));
}
- if(cache_size == 0)
- return -1;
- rewind(cache);
+
+ if(cache_size == 0) return -1;
+
char filename[MAX_FN_LEN];
struct stat file_st;
- long filename_pos = 0;
- for(int i=0, fn_ind=0; i < cache_size;) {
- // TODO handle this better in case EOF is an error
- if((filename[fn_ind]=fgetc(cache)) == EOF) return -1;
- i++;
- if(filename[fn_ind] == '\t') {
- filename[fn_ind] = 0;
- if(!strncmp(filename, key, fn_ind)) {
- //Already exists in cache
- assert(!stat(filename, &file_st));
- if(file_st.st_mtime < cache_mtime) {
- /* Cache entry is up to date */
- return filename_pos;
- }
- /* Not up to date. Caller will create a new cache entry,
- then we will delete this line at the end of the program */
- if(deletables_ind > 49) {
- deletables = realloc(deletables, (deletables_ind + 1) * sizeof(deletables[0]));
- assert(deletables);
- }
- deletables[deletables_ind++] = filename_pos;
- return -1;
+
+ for(ssize_t i=0, line_no=1; i < cache_size; line_no++) {
+ size_t fn_len = 0;
+ size_t fn_begin = i;
+ for(; i < cache_size; i++) {
+ if((filename[i-fn_begin]=cache_buf[i]) == '\t') {
+ fn_len = i - fn_begin;
+ filename[fn_len] = '\0';
+ i++;
+ break;
+ }
+ }
+ assert(fn_len);
+ if(!strncmp(filename, key, fn_len)) {
+ //Already exists in cache
+ assert(!stat(filename, &file_st));
+ if(file_st.st_mtime < cache_mtime) {
+ /* Cache entry is up to date */
+ return i;
}
- fn_ind = 0;
- for(char tmp=fgetc(cache); i < cache_size && tmp != '\n'; i++) {
- if(tmp == EOF) return -1;
- tmp = fgetc(cache);
+ /* Not up to date. Caller will create a new cache entry,
+ then we will delete this line at the end of the program */
+ if(deletables_ind > 49) {
+ deletables = realloc(deletables, (deletables_ind + 1) * sizeof(deletables[0]));
+ assert(deletables);
}
- /* Capture beginning of this line, in case this is the file in question */
- filename_pos = ftell(cache);
+ deletables[deletables_ind++] = fn_begin;
+ return -1;
}
- else fn_ind++;
+ while(cache_buf[i++] != '\n');
}
return -1;
}
static bool cache_fetch_pixel(char *key, Pixel *value) {
- long filename_pos = cache_grep(key);
- if(filename_pos < 0) return false;
+ ssize_t i = cache_grep(key);
+ if(i == -1) return false;
char hexstr[7];
- assert(fgets(hexstr, 7, cache) && strlen(hexstr) == 6);
+ assert(indof(cache_buf + i, '\n', cache_size - i) == 6);
+ hexstr[0] = 0;
+ strncat(hexstr, cache_buf + i, 6);
*value = hexstr_top(hexstr);
return true;
}
static bool cache_put_pixel(char *key, Pixel value) {
- if(!cache) return false;
- fseek(cache, 0, SEEK_END);
- fprintf(cache, "%s\t%02x%02x%02x\n", key, value.r, value.g, value.b);
+ if(!cache_buf) return false;
+ char entry[MAX_FN_LEN + 9];
+ int entry_length = sprintf(entry, "%s\t%02x%02x%02x\n", key, value.r, value.g, value.b);
+ size_t new_size_of_cache = cache_size + entry_length;
+ if(new_size_of_cache > cache_max_size) {
+ assert((cache_buf=realloc(cache_buf, new_size_of_cache)));
+ cache_max_size = new_size_of_cache;
+ }
+ strncat(cache_buf, entry, entry_length);
+ cache_size = new_size_of_cache;
+ cache_mtime = time(NULL);
+ assert(cache_mtime > 0);
return true;
}
@@ -289,7 +336,6 @@ static bool get_resized_pixel_info(char *filename, const size_t width, const siz
return z == pixels_arr_size;
}
else {
- /* TODO delete tempdir at end of execution */
if(files_inner_cached_ind == 0)
mkdtemp(temp_dirname);
const size_t filename_len = strlen(filename);
@@ -542,7 +588,7 @@ int main(int argc, char **argv) {
if(exception->severity != UndefinedException)
CatchException(exception);
-
+ /* Teardown */
if(files_inner_cached) {
for(size_t i=0; i < files_inner_cached_ind; i++) {
if(remove(inner_cache_tmp_files[i])) perror("remove");
@@ -551,50 +597,29 @@ int main(int argc, char **argv) {
}
if(remove(temp_dirname)) perror("remove");
}
- if(cache) {
- fclose(cache);
- char line[MAX_FN_LEN];
- size_t len = strlen(cache_filename);
- char *new_cache_name = malloc(len + 2);
- strcpy(new_cache_name, cache_filename);
- new_cache_name[len] = '2';
- new_cache_name[len+1] = 0;
- cache = fopen(cache_filename, "r");
- errno = 0;
+ if(cache_buf) {
+ FILE *cache = fopen(cache_filename, "w");
if(!cache) {
- WARN("Failed to reopen the cache file '%s' for reading "
+ WARN("Failed to reopen the cache file '%s' for writing "
"in order to update the cache properly:", cache_filename);
perror("fopen");
- }
- FILE *new_cache = fopen(new_cache_name, "w");
- if(!new_cache) {
- WARN("Failed to open file '%s' in order to update the cache properly:", new_cache_name);
- perror("fopen");
- }
- if(errno) {
WARN("The cache at '%s' may now contain duplicate entries.", cache_filename);
}
- else while(1) {
- long pos = ftell(cache);
- if(!fgets(line, MAX_FN_LEN, cache)) break;
+ else for(ssize_t i=0; i < cache_size;) {
bool keep = true;
- for(size_t i=0; i < deletables_ind; i++) {
- if(deletables[i] == pos) {
+ for(size_t j=0; j < deletables_ind; j++) {
+ if(deletables[j] == i) {
keep = false;
break;
}
}
- if(keep) fputs(line, new_cache);
+ size_t line_len = indof(cache_buf + i, '\n', cache_size - i);
+ if(keep) for(size_t j=0; j <= line_len; j++) assert(fputc(cache_buf[i+j], cache) != EOF);
+ i += line_len + 1;
}
+ if(cache) fclose(cache);
free(deletables);
- fclose(cache);
- fclose(new_cache);
- if(rename(new_cache_name, cache_filename)) {
- WARN("Overwriting cache file '%s' failed:", cache_filename);
- perror("rename");
- WARN("The cache at '%s' may now contain duplicate entries.", cache_filename);
- }
- free(new_cache_name);
+ free(cache_buf);
}
if(output_img) {
