# [PATCH] Customizable error handlers 4 messages from 2006-06-23 to 2006-06-23. Participants: Petr Baudis, Junio C Hamano. Thread: https://gitlist.dev/t/4636 ## Petr Baudis, 2006-06-23 13:32 Subject: [PATCH] Customizable error handlers Message-ID: <20060623133227.27854.65567.stgit@machine.or.cz> URL: https://gitlist.dev/e/20060623133227.27854.65567.stgit%40machine.or.cz ``` 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 --- git-compat-util.h | 10 +++++++--- usage.c | 50 +++++++++++++++++++++++++++++++++++++++++++++----- 2 files changed, 52 insertions(+), 8 deletions(-) diff --git a/git-compat-util.h b/git-compat-util.h index 5d543d2..e954002 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -36,9 +36,13 @@ #endif #endif /* General helper functions */ -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))); +void usage(const char *err) NORETURN; +void die(const char *err, ...) NORETURN __attribute__((format (printf, 1, 2))); +int error(const char *err, ...) __attribute__((format (printf, 1, 2))); + +void set_usage_routine(void (*routine)(const char *err) NORETURN); +void set_die_routine(void (*routine)(const char *err, va_list params) NORETURN); +void set_error_routine(int (*routine)(const char *err, va_list params)); #ifdef NO_MMAP diff --git a/usage.c b/usage.c index 1fa924c..445456d 100644 --- a/usage.c +++ b/usage.c @@ -12,28 +12,68 @@ static void report(const char *prefix, c 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); +} + +int error_builtin(const char *err, va_list params) +{ + report("error: ", err, params); + return -1; +} + + +/* 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 int (*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(int (*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, ...) { va_list params; + int ret; va_start(params, err); - report("error: ", err, params); + ret = error_routine(err, params); va_end(params); - return -1; + return ret; } ``` ## Petr Baudis, 2006-06-23 13:38 Subject: Re: [PATCH] Customizable error handlers Message-ID: <20060623133847.GN21864@pasky.or.cz> URL: https://gitlist.dev/e/20060623133847.GN21864%40pasky.or.cz In-Reply-To: <20060623133227.27854.65567.stgit@machine.or.cz> ``` Dear diary, on Fri, Jun 23, 2006 at 03:32:27PM CEST, I got a letter where Petr Baudis said that... > diff --git a/git-compat-util.h b/git-compat-util.h > index 5d543d2..e954002 100644 > --- a/git-compat-util.h > +++ b/git-compat-util.h > @@ -36,9 +36,13 @@ #endif > #endif > > /* General helper functions */ > -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))); > +void usage(const char *err) NORETURN; > +void die(const char *err, ...) NORETURN __attribute__((format (printf, 1, 2))); > +int error(const char *err, ...) __attribute__((format (printf, 1, 2))); Wah, this kind of slipped through. Below is a patch without the externs removed. Sorry about the noise. > int error(const char *err, ...) > { > va_list params; > + int ret; > > va_start(params, err); > - report("error: ", err, params); > + ret = error_routine(err, params); > va_end(params); > - return -1; > + return ret; > } BTW, I don't mind if you just force the return value to -1 here. It might be saner. --- [PATCH] 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 --- diff --git a/git-compat-util.h b/git-compat-util.h index 5d543d2..0c5ceb3 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -40,6 +40,10 @@ extern void usage(const char *err) NORET 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(int (*routine)(const char *err, va_list params)); + #ifdef NO_MMAP #ifndef PROT_READ diff --git a/usage.c b/usage.c index 1fa924c..445456d 100644 --- a/usage.c +++ b/usage.c @@ -12,28 +12,68 @@ static void report(const char *prefix, c 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); +} + +int error_builtin(const char *err, va_list params) +{ + report("error: ", err, params); + return -1; +} + + +/* 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 int (*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(int (*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, ...) { va_list params; + int ret; va_start(params, err); - report("error: ", err, params); + ret = error_routine(err, params); va_end(params); - return -1; + return ret; } -- Petr "Pasky" Baudis Stuff: http://pasky.or.cz/ A person is just about as big as the things that make them angry. ``` ## Junio C Hamano, 2006-06-23 23:14 Subject: Re: [PATCH] Customizable error handlers Message-ID: <7vsllv8ny8.fsf@assigned-by-dhcp.cox.net> URL: https://gitlist.dev/e/7vsllv8ny8.fsf%40assigned-by-dhcp.cox.net In-Reply-To: <20060623133847.GN21864@pasky.or.cz> ``` Petr Baudis writes: > Dear diary, on Fri, Jun 23, 2006 at 03:32:27PM CEST, I got a letter > where Petr Baudis said that... >> diff --git a/git-compat-util.h b/git-compat-util.h >> index 5d543d2..e954002 100644 >> --- a/git-compat-util.h >> +++ b/git-compat-util.h >> @@ -36,9 +36,13 @@ #endif >> #endif >> >> /* General helper functions */ >> -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))); >> +void usage(const char *err) NORETURN; >> +void die(const char *err, ...) NORETURN __attribute__((format (printf, 1, 2))); >> +int error(const char *err, ...) __attribute__((format (printf, 1, 2))); > > Wah, this kind of slipped through. Below is a patch without the > externs removed. Oh, I first thought you did that on purpose as a cleanup. After all don't they mean the same thing? ``` ## Petr Baudis, 2006-06-23 23:18 Subject: Re: [PATCH] Customizable error handlers Message-ID: <20060623231807.GO21864@pasky.or.cz> URL: https://gitlist.dev/e/20060623231807.GO21864%40pasky.or.cz In-Reply-To: <7vsllv8ny8.fsf@assigned-by-dhcp.cox.net> ``` Dear diary, on Sat, Jun 24, 2006 at 01:14:07AM CEST, I got a letter where Junio C Hamano said that... > Petr Baudis writes: > > > Dear diary, on Fri, Jun 23, 2006 at 03:32:27PM CEST, I got a letter > > where Petr Baudis said that... > >> diff --git a/git-compat-util.h b/git-compat-util.h > >> index 5d543d2..e954002 100644 > >> --- a/git-compat-util.h > >> +++ b/git-compat-util.h > >> @@ -36,9 +36,13 @@ #endif > >> #endif > >> > >> /* General helper functions */ > >> -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))); > >> +void usage(const char *err) NORETURN; > >> +void die(const char *err, ...) NORETURN __attribute__((format (printf, 1, 2))); > >> +int error(const char *err, ...) __attribute__((format (printf, 1, 2))); > > > > Wah, this kind of slipped through. Below is a patch without the > > externs removed. > > Oh, I first thought you did that on purpose as a cleanup. After > all don't they mean the same thing? AFAIK they do, but we use extern everywhere and I personally consider it good style to externize declarations of, well, external functions. -- Petr "Pasky" Baudis Stuff: http://pasky.or.cz/ A person is just about as big as the things that make them angry. ```