unpack-trees: allow Porcelain to give different error messages

diff --git a/write_or_die.c b/write_or_die.c
index 5c4bc8515ab9484131de7e065e08657315004f8c..32f99140205f8969d8a884b3cf9448eec3f1dd16 100644 (file)
--- a/write_or_die.c
+++ b/write_or_die.c
@@ -1,6 +1,46 @@
 #include "cache.h"
 
-int read_in_full(int fd, void *buf, size_t count)
+/*
+ * Some cases use stdio, but want to flush after the write
+ * to get error handling (and to get better interactive
+ * behaviour - not buffering excessively).
+ *
+ * Of course, if the flush happened within the write itself,
+ * we've already lost the error code, and cannot report it any
+ * more. So we just ignore that case instead (and hope we get
+ * the right error code on the flush).
+ *
+ * If the file handle is stdout, and stdout is a file, then skip the
+ * flush entirely since it's not needed.
+ */
+void maybe_flush_or_die(FILE *f, const char *desc)
+{
+       static int skip_stdout_flush = -1;
+       struct stat st;
+       char *cp;
+
+       if (f == stdout) {
+               if (skip_stdout_flush < 0) {
+                       cp = getenv("GIT_FLUSH");
+                       if (cp)
+                               skip_stdout_flush = (atoi(cp) == 0);
+                       else if ((fstat(fileno(stdout), &st) == 0) &&
+                                S_ISREG(st.st_mode))
+                               skip_stdout_flush = 1;
+                       else
+                               skip_stdout_flush = 0;
+               }
+               if (skip_stdout_flush && !ferror(f))
+                       return;
+       }
+       if (fflush(f)) {
+               if (errno == EPIPE)
+                       exit(0);
+               die("write failure on %s: %s", desc, strerror(errno));
+       }
+}
+
+ssize_t read_in_full(int fd, void *buf, size_t count)
 {
        char *p = buf;
        ssize_t total = 0;
@@ -17,7 +57,7 @@ int read_in_full(int fd, void *buf, size_t count)
        return total;
 }
 
-int write_in_full(int fd, const void *buf, size_t count)
+ssize_t write_in_full(int fd, const void *buf, size_t count)
 {
        const char *p = buf;
        ssize_t total = 0;