Customizable error handlers

This patch makes the usage(), die() and error() handlers customizable.
Nothing in the git code itself uses that but many other libgit users
(like Git.pm) will.

This is implemented using the mutator functions primarily because you
cannot directly modifying global variables of libgit from a program that
dlopen()ed it, apparently. But having functions for that is a better API
anyway.

Signed-off-by: Petr Baudis <pasky@suse.cz>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/git-compat-util.h b/git-compat-util.h
index 5d543d29f85e432a89bb8cbfbe2d18205599b06f..b3d4cf532e5728e6b962d0d65789f6e8e4bd7fe5 100644 (file)
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -40,6 +40,10 @@ extern void usage(const char *err) NORETURN;
 extern void die(const char *err, ...) NORETURN __attribute__((format (printf, 1, 2)));
 extern int error(const char *err, ...) __attribute__((format (printf, 1, 2)));
 
+extern void set_usage_routine(void (*routine)(const char *err) NORETURN);
+extern void set_die_routine(void (*routine)(const char *err, va_list params) NORETURN);
+extern void set_error_routine(void (*routine)(const char *err, va_list params));
+
 #ifdef NO_MMAP
 
 #ifndef PROT_READ

diff --git a/usage.c b/usage.c
index 1fa924c3d9ed8f70523685c26cf169316b366598..b781b0061ea5a100ac8f86a0a87d4ac92c77c407 100644 (file)
--- a/usage.c
+++ b/usage.c
@@ -12,20 +12,58 @@ static void report(const char *prefix, const char *err, va_list params)
        fputs("\n", stderr);
 }
 
-void usage(const char *err)
+void usage_builtin(const char *err)
 {
        fprintf(stderr, "usage: %s\n", err);
        exit(129);
 }
 
+void die_builtin(const char *err, va_list params)
+{
+       report("fatal: ", err, params);
+       exit(128);
+}
+
+void error_builtin(const char *err, va_list params)
+{
+       report("error: ", err, params);
+}
+
+
+/* If we are in a dlopen()ed .so write to a global variable would segfault
+ * (ugh), so keep things static. */
+static void (*usage_routine)(const char *err) NORETURN = usage_builtin;
+static void (*die_routine)(const char *err, va_list params) NORETURN = die_builtin;
+static void (*error_routine)(const char *err, va_list params) = error_builtin;
+
+void set_usage_routine(void (*routine)(const char *err) NORETURN)
+{
+       usage_routine = routine;
+}
+
+void set_die_routine(void (*routine)(const char *err, va_list params) NORETURN)
+{
+       die_routine = routine;
+}
+
+void set_error_routine(void (*routine)(const char *err, va_list params))
+{
+       error_routine = routine;
+}
+
+
+void usage(const char *err)
+{
+       usage_routine(err);
+}
+
 void die(const char *err, ...)
 {
        va_list params;
 
        va_start(params, err);
-       report("fatal: ", err, params);
+       die_routine(err, params);
        va_end(params);
-       exit(128);
 }
 
 int error(const char *err, ...)
@@ -33,7 +71,7 @@ int error(const char *err, ...)
        va_list params;
 
        va_start(params, err);
-       report("error: ", err, params);
+       error_routine(err, params);
        va_end(params);
        return -1;
 }