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authorMike Frysinger <vapier@gentoo.org>2022-12-24 15:02:00 -0500
committerMike Frysinger <vapier@gentoo.org>2022-12-24 21:33:24 -0500
commita5f08108c14ed37cd9f71e0828876d96e9de46da (patch)
treee9e7f127f5c80defb349db29e9f1fb078298ca22 /sim/ppc/lf.c
parent5d3539bd6bbd9cbd0fa1e09d93632ff08822f1c2 (diff)
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sim: igen: support in-place updates ourself
Every file that igen outputs is then processed with the move-if-changed shell script. This creates a lot of boilerplate in the build and not an insignificant amount of build-time overhead. Move the simple "is the file changed" logic into igen itself.
Diffstat (limited to 'sim/ppc/lf.c')
-rw-r--r--sim/ppc/lf.c85
1 files changed, 76 insertions, 9 deletions
diff --git a/sim/ppc/lf.c b/sim/ppc/lf.c
index c40de5b..e170a47 100644
--- a/sim/ppc/lf.c
+++ b/sim/ppc/lf.c
@@ -17,7 +17,7 @@
*/
-
+#include <stdbool.h>
#include <stdio.h>
#include <stdarg.h>
#include <ctype.h>
@@ -34,7 +34,9 @@ struct _lf {
int line_nr; /* nr complete lines written, curr line is line_nr+1 */
int indent;
int line_blank;
- const char *name;
+ const char *name; /* Output name with diagnostics. */
+ const char *filename; /* Output filename. */
+ char *tmpname; /* Temporary output filename. */
const char *program;
lf_file_references references;
lf_file_type type;
@@ -54,6 +56,7 @@ lf_open(const char *name,
new_lf->references = references;
new_lf->type = type;
new_lf->name = (real_name == NULL ? name : real_name);
+ new_lf->filename = name;
new_lf->program = program;
/* attach to stdout if pipe */
if (!strcmp(name, "-")) {
@@ -61,7 +64,11 @@ lf_open(const char *name,
}
else {
/* create a new file */
- new_lf->stream = fopen(name, "w");
+ char *tmpname = zalloc (strlen (name) + 5);
+ sprintf (tmpname, "%s.tmp", name);
+ new_lf->filename = name;
+ new_lf->tmpname = tmpname;
+ new_lf->stream = fopen(tmpname, "w+");
if (new_lf->stream == NULL) {
perror(name);
exit(1);
@@ -74,13 +81,73 @@ lf_open(const char *name,
void
lf_close(lf *file)
{
- if (file->stream != stdout) {
- if (fclose(file->stream)) {
- perror("lf_close.fclose");
- exit(1);
+ FILE *fp;
+ bool update = true;
+
+ /* If we wrote to stdout, no house keeping needed. */
+ if (file->stream == stdout)
+ return;
+
+ /* Rename the temp file to the real file if it's changed. */
+ fp = fopen (file->filename, "r");
+ if (fp != NULL)
+ {
+ off_t len;
+
+ fseek (fp, 0, SEEK_END);
+ len = ftell (fp);
+
+ if (len == ftell (file->stream))
+ {
+ off_t off;
+ size_t cnt;
+ char *oldbuf = zalloc (len);
+ char *newbuf = zalloc (len);
+
+ rewind (fp);
+ off = 0;
+ while ((cnt = fread (oldbuf + off, 1, len - off, fp)) > 0)
+ off += cnt;
+ ASSERT (off == len);
+
+ rewind (file->stream);
+ off = 0;
+ while ((cnt = fread (newbuf + off, 1, len - off, file->stream)) > 0)
+ off += cnt;
+ ASSERT (off == len);
+
+ if (memcmp (oldbuf, newbuf, len) == 0)
+ update = false;
+ }
+
+ fclose (fp);
}
- free(file);
- }
+
+ if (fclose (file->stream))
+ {
+ perror ("lf_close.fclose");
+ exit (1);
+ }
+
+ if (update)
+ {
+ if (rename (file->tmpname, file->filename) != 0)
+ {
+ perror ("lf_close.rename");
+ exit (1);
+ }
+ }
+ else
+ {
+ if (remove (file->tmpname) != 0)
+ {
+ perror ("lf_close.unlink");
+ exit (1);
+ }
+ }
+
+ free (file->tmpname);
+ free (file);
}