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(svn r22254) -Codechange: Make settingsgen only update the output file if it actually changed.

release/1.2
michi_cc 2011-03-14 22:24:08 +00:00
parent f81dd357e8
commit e7bb220fdd
1 changed files with 53 additions and 2 deletions
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55
src/settingsgen/settingsgen.cpp
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@ -18,6 +18,11 @@
#include <stdarg.h> #include <stdarg.h>
#if (!defined(WIN32) && !defined(WIN64)) || defined(__CYGWIN__)
#include <unistd.h>
#include <sys/stat.h>
#endif
#ifdef __MORPHOS__ #ifdef __MORPHOS__
#ifdef stderr #ifdef stderr
#undef stderr #undef stderr
@ -347,6 +352,39 @@ static void CopyFile(const char *fname, FILE *out_fp)
fclose(in_fp); fclose(in_fp);
} }
/**
* Compare two files for identity.
* @param n1 First file.
* @param n2 Second file.
* @return True if both files are identical.
*/
static bool CompareFiles(const char *n1, const char *n2)
{
FILE *f2 = fopen(n2, "rb");
if (f2 == NULL) return false;
FILE *f1 = fopen(n1, "rb");
if (f1 == NULL) error("can't open %s", n1);
size_t l1, l2;
do {
char b1[4096];
char b2[4096];
l1 = fread(b1, 1, sizeof(b1), f1);
l2 = fread(b2, 1, sizeof(b2), f2);
if (l1 != l2 || memcmp(b1, b2, l1) != 0) {
fclose(f2);
fclose(f1);
return false;
}
} while (l1 != 0);
fclose(f2);
fclose(f1);
return true;
}
/** Options of settingsgen. */ /** Options of settingsgen. */
static const OptionData _opts[] = { static const OptionData _opts[] = {
GETOPT_NOVAL( 'v', "--version"), GETOPT_NOVAL( 'v', "--version"),
@ -447,15 +485,28 @@ int CDECL main(int argc, char *argv[])
_stored_output.Write(stdout); _stored_output.Write(stdout);
CopyFile(after_file, stdout); CopyFile(after_file, stdout);
} else { } else {
FILE *fp = fopen(output_file, "w"); static const char * const tmp_output = "tmp2.xxx";
FILE *fp = fopen(tmp_output, "w");
if (fp == NULL) { if (fp == NULL) {
fprintf(stderr, "settingsgen: Warning: Cannot open file %s\n", output_file); fprintf(stderr, "settingsgen: Warning: Cannot open file %s\n", tmp_output);
return 1; return 1;
} }
CopyFile(before_file, fp); CopyFile(before_file, fp);
_stored_output.Write(fp); _stored_output.Write(fp);
CopyFile(after_file, fp); CopyFile(after_file, fp);
fclose(fp); fclose(fp);
if (CompareFiles(tmp_output, output_file)) {
/* Files are equal. tmp2.xxx is not needed. */
unlink(tmp_output);
} else {
/* Rename tmp2.xxx to output file. */
#if defined(WIN32) || defined(WIN64)
unlink(output_file);
#endif
if (rename(tmp_output, output_file) == -1) error("rename() failed");
}
} }
return 0; return 0;
} }