* stream.c (tail_strategy): Execute the strategy code also

in the case that the stream's FILE * handle is null. This handles
opening the file for the first time.
(make_stdio_stream_common): Do not use the FILE * handle if it is null.
(open_tail): Do not open the file immediately and error out.
This is undesirable because log files might not exist at the time
open_tail is called on them. Instead, produce a stream which contains
a null file handle, and use tail_strategy to poll for the file
to come into existence.

* utf8.c (w_freopen): Just in case freopen doesn't like a null
pointer for the existing stream, use fopen instead if that is the case.

3 files changed, 24 insertions, 17 deletions

diff --git a/ChangeLog b/ChangeLog
index ca50a21c..ed2b531b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,20 @@
 2013-12-02  Kaz Kylheku  <kaz@kylheku.com>
 
+	* stream.c (tail_strategy): Execute the strategy code also
+	in the case that the stream's FILE * handle is null. This handles
+	opening the file for the first time.
+	(make_stdio_stream_common): Do not use the FILE * handle if it is null.
+	(open_tail): Do not open the file immediately and error out.
+	This is undesirable because log files might not exist at the time
+	open_tail is called on them. Instead, produce a stream which contains
+	a null file handle, and use tail_strategy to poll for the file
+	to come into existence.
+
+	* utf8.c (w_freopen): Just in case freopen doesn't like a null
+	pointer for the existing stream, use fopen instead if that is the case.
+
+2013-12-02  Kaz Kylheku  <kaz@kylheku.com>
+
 	* genvim.txr: Missing catch and finally keywords added.
 
 	* txr.vim: Regenerated.
diff --git a/stream.c b/stream.c
index 8bae32eb..b401c911 100644
--- a/stream.c
+++ b/stream.c
@@ -360,17 +360,17 @@ static void tail_calc(unsigned long *state, int *sec, int *mod)
 
 static void tail_strategy(val stream, unsigned long *state)
 {
+  struct stdio_handle *h = (struct stdio_handle *) stream->co.handle;
   int sec, mod;
 
   tail_calc(state, &sec, &mod);
 
   sleep(sec);
 
-  if (*state % mod == 0) {
-    struct stdio_handle *h = (struct stdio_handle *) stream->co.handle;
-    long save_pos, size;
+  if (*state % mod == 0 || h->f == 0) {
+    long save_pos = 0, size;
 
-    if ((save_pos = ftell(h->f)) == -1)
+    if (h->f != 0 && (save_pos = ftell(h->f)) == -1)
       return;
 
     for (;;) {
@@ -925,7 +925,7 @@ static val make_stdio_stream_common(FILE *f, val descr, struct cobj_ops *ops)
   utf8_decoder_init(&h->ud);
   h->pid = 0;
 #if HAVE_ISATTY
-  h->is_real_time = (isatty(fileno(h->f)) == 1);
+  h->is_real_time = (h->f != 0 && isatty(fileno(h->f)) == 1);
 #else
   h->is_real_time = 0;
 #endif
@@ -1798,22 +1798,14 @@ val open_file(val path, val mode_str)
 
 val open_tail(val path, val mode_str, val seek_end_p)
 {
-  FILE *f = w_fopen(c_str(path), c_str(mode_str));
   struct stdio_handle *h;
   val stream;
+  unsigned long state = 0;
 
-  if (!f)
-    uw_throwf(file_error_s, lit("error opening ~a: ~a/~s"),
-              path, num(errno), string_utf8(strerror(errno)), nao);
-
-  if (seek_end_p)
-    if (fseek(f, 0, SEEK_END) < 0)
-      uw_throwf(file_error_s, lit("error seeking to end of ~a: ~a/~s"),
-                path, num(errno), string_utf8(strerror(errno)), nao);
-
-  stream = make_tail_stream(f, path);
+  stream = make_tail_stream(0, path);
   h = (struct stdio_handle *) stream->co.handle;
   h->mode = mode_str;
+  tail_strategy(stream, &state);
   return stream;
 }
 
diff --git a/utf8.c b/utf8.c
index 99e21978..a65c864e 100644
--- a/utf8.c
+++ b/utf8.c
@@ -376,7 +376,7 @@ FILE *w_freopen(const wchar_t *wname, const wchar_t *wmode, FILE *fold)
 {
   char *name = utf8_dup_to(wname);
   char *mode = utf8_dup_to(wmode);
-  FILE *f = freopen(name, mode, fold);
+  FILE *f = fold ? freopen(name, mode, fold) : fopen(name, mode);
   free(name);
   free(mode);
   return f;