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authormichi_cc <michi_cc@openttd.org>2011-03-14 22:24:08 +0000
committermichi_cc <michi_cc@openttd.org>2011-03-14 22:24:08 +0000
commite7bb220fdd8f96c99d9823c5059c41f71cb4267b (patch)
tree303fcaf36ac326aabfc1acb1a209b42040667e71 /src/settingsgen
parentf81dd357e8178d9f58f81dec64df5625189e9192 (diff)
downloadopenttd-e7bb220fdd8f96c99d9823c5059c41f71cb4267b.tar.xz
(svn r22254) -Codechange: Make settingsgen only update the output file if it actually changed.
Diffstat (limited to 'src/settingsgen')
-rw-r--r--src/settingsgen/settingsgen.cpp55
1 files changed, 53 insertions, 2 deletions
diff --git a/src/settingsgen/settingsgen.cpp b/src/settingsgen/settingsgen.cpp
index 16300292a..faedc3df0 100644
--- a/src/settingsgen/settingsgen.cpp
+++ b/src/settingsgen/settingsgen.cpp
@@ -18,6 +18,11 @@
#include <stdarg.h>
+#if (!defined(WIN32) && !defined(WIN64)) || defined(__CYGWIN__)
+#include <unistd.h>
+#include <sys/stat.h>
+#endif
+
#ifdef __MORPHOS__
#ifdef stderr
#undef stderr
@@ -347,6 +352,39 @@ static void CopyFile(const char *fname, FILE *out_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. */
static const OptionData _opts[] = {
GETOPT_NOVAL( 'v', "--version"),
@@ -447,15 +485,28 @@ int CDECL main(int argc, char *argv[])
_stored_output.Write(stdout);
CopyFile(after_file, stdout);
} else {
- FILE *fp = fopen(output_file, "w");
+ static const char * const tmp_output = "tmp2.xxx";
+
+ FILE *fp = fopen(tmp_output, "w");
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;
}
CopyFile(before_file, fp);
_stored_output.Write(fp);
CopyFile(after_file, 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;
}