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input: Clean up input file scanning 

Do not use Unix low-level I/O for reading a regular input file.
Read in the file header once and re-use the buffer for all input
modules participating in the scan. Also re-use a prefilled metadata
table instead of creating it anew for each input module tried.
This commit is contained in:
Daniel Elstner 2015-09-19 00:24:50 +02:00
parent ff85d65ec6
commit 5e364d4fe0
1 changed files with 46 additions and 54 deletions
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100
src/input/input.c
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@ -24,6 +24,8 @@
#include <unistd.h> #include <unistd.h>
#include <fcntl.h> #include <fcntl.h>
#include <errno.h> #include <errno.h>
#include <glib.h>
#include <glib/gstdio.h>
#include <libsigrok/libsigrok.h> #include <libsigrok/libsigrok.h>
#include "libsigrok-internal.h" #include "libsigrok-internal.h"
@ -414,14 +416,17 @@ SR_API int sr_input_scan_buffer(GString *buf, const struct sr_input **in)
*/ */
SR_API int sr_input_scan_file(const char *filename, const struct sr_input **in) SR_API int sr_input_scan_file(const char *filename, const struct sr_input **in)
{ {
FILE *stream;
const struct sr_input_module *imod; const struct sr_input_module *imod;
GHashTable *meta; GHashTable *meta;
GString *header_buf; GString *header;
struct stat st; struct stat st;
unsigned int midx, m, i; size_t count;
int fd, ret; unsigned int midx, i;
ssize_t size; int ret;
uint8_t mitem, avail_metadata[8]; uint8_t avail_metadata[8];
*in = NULL;
if (!filename || !filename[0]) { if (!filename || !filename[0]) {
sr_err("Invalid filename."); sr_err("Invalid filename.");
@ -438,18 +443,41 @@ SR_API int sr_input_scan_file(const char *filename, const struct sr_input **in)
return SR_ERR_ARG; return SR_ERR_ARG;
} }
stream = g_fopen(filename, "rb");
if (!stream) {
sr_err("Failed to open %s: %s", filename, g_strerror(errno));
return SR_ERR;
}
/* This actually allocates 256 bytes to allow for NUL termination. */
header = g_string_sized_new(255);
count = fread(header->str, 1, header->allocated_len - 1, stream);
if (count != header->allocated_len - 1 && ferror(stream)) {
sr_err("Failed to read %s: %s", filename, g_strerror(errno));
fclose(stream);
g_string_free(header, TRUE);
return SR_ERR;
}
fclose(stream);
g_string_set_size(header, count);
meta = g_hash_table_new(NULL, NULL);
g_hash_table_insert(meta, GINT_TO_POINTER(SR_INPUT_META_FILENAME),
(char *)filename);
g_hash_table_insert(meta, GINT_TO_POINTER(SR_INPUT_META_FILESIZE),
GSIZE_TO_POINTER(st.st_size));
g_hash_table_insert(meta, GINT_TO_POINTER(SR_INPUT_META_HEADER),
header);
midx = 0; midx = 0;
avail_metadata[midx++] = SR_INPUT_META_FILENAME; avail_metadata[midx++] = SR_INPUT_META_FILENAME;
avail_metadata[midx++] = SR_INPUT_META_FILESIZE; avail_metadata[midx++] = SR_INPUT_META_FILESIZE;
avail_metadata[midx++] = SR_INPUT_META_HEADER; avail_metadata[midx++] = SR_INPUT_META_HEADER;
avail_metadata[midx] = 0;
/* TODO: MIME type */ /* TODO: MIME type */
*in = NULL;
ret = SR_ERR; ret = SR_ERR;
header_buf = g_string_sized_new(128);
for (i = 0; input_module_list[i]; i++) {
g_string_truncate(header_buf, 0);
for (i = 0; input_module_list[i]; i++) {
imod = input_module_list[i]; imod = input_module_list[i];
if (!imod->metadata[0]) { if (!imod->metadata[0]) {
/* Module has no metadata for matching so will take /* Module has no metadata for matching so will take
@ -460,60 +488,24 @@ SR_API int sr_input_scan_file(const char *filename, const struct sr_input **in)
/* Cannot satisfy this module's requirements. */ /* Cannot satisfy this module's requirements. */
continue; continue;
meta = g_hash_table_new(NULL, NULL); sr_dbg("Trying module %s.", imod->id);
for (m = 0; m < sizeof(imod->metadata); m++) {
mitem = imod->metadata[m] & ~SR_INPUT_META_REQUIRED;
if (!mitem)
/* Metadata list is 0-terminated. */
break;
if (mitem == SR_INPUT_META_FILENAME) {
g_hash_table_insert(meta, GINT_TO_POINTER(mitem),
(gpointer)filename);
} else if (mitem == SR_INPUT_META_FILESIZE) {
g_hash_table_insert(meta, GINT_TO_POINTER(mitem),
GINT_TO_POINTER(st.st_size));
} else if (mitem == SR_INPUT_META_HEADER) {
if ((fd = open(filename, O_RDONLY)) < 0) {
sr_err("%s", g_strerror(errno));
return SR_ERR;
}
size = read(fd, header_buf->str, 128);
header_buf->len = size;
close(fd);
if (size <= 0) {
g_string_free(header_buf, TRUE);
sr_err("%s", g_strerror(errno));
return SR_ERR;
}
g_hash_table_insert(meta, GINT_TO_POINTER(mitem), header_buf);
}
}
if (g_hash_table_size(meta) == 0) {
/* No metadata for this module, so there's no way it
* can match. */
g_hash_table_destroy(meta);
continue;
}
sr_spew("Trying module %s.", imod->id);
ret = imod->format_match(meta); ret = imod->format_match(meta);
g_hash_table_destroy(meta); if (ret == SR_ERR) {
if (ret == SR_ERR_DATA) {
/* Module recognized this buffer, but cannot handle it. */
break;
} else if (ret == SR_ERR) {
/* Module didn't recognize this buffer. */ /* Module didn't recognize this buffer. */
continue; continue;
} else if (ret != SR_OK) { } else if (ret != SR_OK) {
/* Can be SR_ERR_NA. */ /* Module recognized this buffer, but cannot handle it. */
return ret; break;
} }
/* Found a matching module. */ /* Found a matching module. */
sr_spew("Module %s matched.", imod->id); sr_dbg("Module %s matched.", imod->id);
*in = sr_input_new(imod, NULL); *in = sr_input_new(imod, NULL);
break; break;
} }
g_string_free(header_buf, TRUE); g_hash_table_destroy(meta);
g_string_free(header, TRUE);
return ret; return ret;
} }