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From: Emily Shaffer <emilyshaffer@google.com>
To: Heba Waly via GitGitGadget <gitgitgadget@gmail.com>
Cc: git@vger.kernel.org, Heba Waly <heba.waly@gmail.com>,
	Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH v2 11/20] sigchain: move doc to sigchain.h
Date: Wed, 6 Nov 2019 14:03:24 -0800	[thread overview]
Message-ID: <20191106220324.GD229589@google.com> (raw)
In-Reply-To: <3499b99538425f9605fead842c10bc63238f94b9.1573034387.git.gitgitgadget@gmail.com>

On Wed, Nov 06, 2019 at 09:59:38AM +0000, Heba Waly via GitGitGadget wrote:
> From: Heba Waly <heba.waly@gmail.com>
> 
> Move the documentation from Documentation/technical/api-sigchain.txt
> to sigchain.h as it's easier for the developers to find the usage
> information beside the code instead of looking for it in another doc file.
> 
> Also documentation/technical/api-sigchain.txt is removed because the
> information it has is now redundant and it'll be hard to keep it up to
> date and synchronized with the documentation in the header file.
> 
> Signed-off-by: Heba Waly <heba.waly@gmail.com>
> ---
>  Documentation/technical/api-sigchain.txt | 41 -----------------------
>  sigchain.h                               | 42 ++++++++++++++++++++++++
>  2 files changed, 42 insertions(+), 41 deletions(-)
>  delete mode 100644 Documentation/technical/api-sigchain.txt
> 
> diff --git a/Documentation/technical/api-sigchain.txt b/Documentation/technical/api-sigchain.txt
> deleted file mode 100644
> index 9e1189ef01..0000000000
> --- a/Documentation/technical/api-sigchain.txt
> +++ /dev/null
> @@ -1,41 +0,0 @@
> -sigchain API
> -============
> -
> -Code often wants to set a signal handler to clean up temporary files or
> -other work-in-progress when we die unexpectedly. For multiple pieces of
> -code to do this without conflicting, each piece of code must remember
> -the old value of the handler and restore it either when:
> -
> -  1. The work-in-progress is finished, and the handler is no longer
> -     necessary. The handler should revert to the original behavior
> -     (either another handler, SIG_DFL, or SIG_IGN).
> -
> -  2. The signal is received. We should then do our cleanup, then chain
> -     to the next handler (or die if it is SIG_DFL).
> -
> -Sigchain is a tiny library for keeping a stack of handlers. Your handler
> -and installation code should look something like:
> -
> -------------------------------------------
> -  void clean_foo_on_signal(int sig)
> -  {
> -	  clean_foo();
> -	  sigchain_pop(sig);
> -	  raise(sig);
> -  }
> -
> -  void other_func()
> -  {
> -	  sigchain_push_common(clean_foo_on_signal);
> -	  mess_up_foo();
> -	  clean_foo();
> -  }
> -------------------------------------------
> -
> -Handlers are given the typedef of sigchain_fun. This is the same type
> -that is given to signal() or sigaction(). It is perfectly reasonable to
> -push SIG_DFL or SIG_IGN onto the stack.
> -
> -You can sigchain_push and sigchain_pop individual signals. For
> -convenience, sigchain_push_common will push the handler onto the stack
> -for many common signals.
> diff --git a/sigchain.h b/sigchain.h
> index 138b20f54b..a990f18cf6 100644
> --- a/sigchain.h
> +++ b/sigchain.h
> @@ -1,12 +1,54 @@
>  #ifndef SIGCHAIN_H
>  #define SIGCHAIN_H
>  
> +/**
> + * Code often wants to set a signal handler to clean up temporary files or
> + * other work-in-progress when we die unexpectedly. For multiple pieces of
> + * code to do this without conflicting, each piece of code must remember
> + * the old value of the handler and restore it either when:
> + *
> + *   1. The work-in-progress is finished, and the handler is no longer
> + *      necessary. The handler should revert to the original behavior
> + *      (either another handler, SIG_DFL, or SIG_IGN).
> + *
> + *   2. The signal is received. We should then do our cleanup, then chain
> + *      to the next handler (or die if it is SIG_DFL).
> + *
> + * Sigchain is a tiny library for keeping a stack of handlers. Your handler
> + * and installation code should look something like:
> + *
> + * ------------------------------------------
> + *   void clean_foo_on_signal(int sig)
> + *   {
> + * 	  clean_foo();
> + * 	  sigchain_pop(sig);
> + * 	  raise(sig);
> + *   }
> + *
> + *   void other_func()
> + *   {
> + * 	  sigchain_push_common(clean_foo_on_signal);
> + * 	  mess_up_foo();
> + * 	  clean_foo();
> + *   }
> + * ------------------------------------------
> + *
> + */
> +
> +/**
> + * Handlers are given the typedef of sigchain_fun. This is the same type
> + * that is given to signal() or sigaction(). It is perfectly reasonable to
> + * push SIG_DFL or SIG_IGN onto the stack.
> + */
>  typedef void (*sigchain_fun)(int);
>  
> +/* You can sigchain_push and sigchain_pop individual signals. */
>  int sigchain_push(int sig, sigchain_fun f);
>  int sigchain_pop(int sig);
>  
> +/* push the handler onto the stack for many common signals. */
It was lacking in the original doc too, but I want to know which common
signals it pushes for. Is it too much work for you to peek in the
implementation and let us know?
>  void sigchain_push_common(sigchain_fun f);
> +
>  void sigchain_pop_common(void);
>  
>  #endif /* SIGCHAIN_H */
> -- 
> gitgitgadget
> 

Otherwise this one looks fine for me.

 - Emily

  reply	other threads:[~2019-11-06 22:03 UTC|newest]

Thread overview: 123+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-29 10:00 [PATCH 00/10] [Outreachy] Move doc to header files Heba Waly via GitGitGadget
2019-10-29 10:00 ` [PATCH 01/10] diff: move doc to diff.h and diffcore.h Heba Waly via GitGitGadget
2019-10-29 10:00 ` [PATCH 02/10] dir: move doc to dir.h Heba Waly via GitGitGadget
2019-10-29 10:00 ` [PATCH 03/10] graph: move doc to graph.h and graph.c Heba Waly via GitGitGadget
2019-10-29 10:00 ` [PATCH 04/10] merge: move doc to ll-merge.h Heba Waly via GitGitGadget
2019-10-30 22:09   ` Elijah Newren
2019-10-31 19:35     ` Heba Waly
2019-11-02  4:28     ` Junio C Hamano
2019-10-29 10:00 ` [PATCH 05/10] sha1-array: move doc to sha1-array.h Heba Waly via GitGitGadget
2019-10-29 10:00 ` [PATCH 06/10] remote: move doc to remote.h and refspec.h Heba Waly via GitGitGadget
2019-10-29 10:00 ` [PATCH 07/10] refs: move doc to refs.h Heba Waly via GitGitGadget
2019-10-29 10:00 ` [PATCH 08/10] attr: move doc to attr.h Heba Waly via GitGitGadget
2019-10-29 10:00 ` [PATCH 09/10] revision: move doc to revision.h Heba Waly via GitGitGadget
2019-10-29 23:57   ` Emily Shaffer
2019-10-29 10:00 ` [PATCH 10/10] pathspec: move doc to pathspec.h Heba Waly via GitGitGadget
2019-11-06  9:59 ` [PATCH v2 00/20] [Outreachy] Move doc to header files Heba Waly via GitGitGadget
2019-11-06  9:59   ` [PATCH v2 01/20] diff: move doc to diff.h and diffcore.h Heba Waly via GitGitGadget
2019-11-06  9:59   ` [PATCH v2 02/20] dir: move doc to dir.h Heba Waly via GitGitGadget
2019-11-07  1:16     ` Emily Shaffer
2019-11-11  0:20       ` Heba Waly
2019-11-06  9:59   ` [PATCH v2 03/20] graph: move doc to graph.h and graph.c Heba Waly via GitGitGadget
2019-11-06  9:59   ` [PATCH v2 04/20] merge: move doc to ll-merge.h Heba Waly via GitGitGadget
2019-11-06  9:59   ` [PATCH v2 05/20] sha1-array: move doc to sha1-array.h Heba Waly via GitGitGadget
2019-11-06  9:59   ` [PATCH v2 06/20] remote: move doc to remote.h and refspec.h Heba Waly via GitGitGadget
2019-11-06  9:59   ` [PATCH v2 07/20] refs: move doc to refs.h Heba Waly via GitGitGadget
2019-11-06  9:59   ` [PATCH v2 08/20] attr: move doc to attr.h Heba Waly via GitGitGadget
2019-11-06  9:59   ` [PATCH v2 09/20] revision: move doc to revision.h Heba Waly via GitGitGadget
2019-11-06  9:59   ` [PATCH v2 10/20] pathspec: move doc to pathspec.h Heba Waly via GitGitGadget
2019-11-07  1:26     ` Emily Shaffer
2019-11-10  1:40       ` Heba Waly
2019-11-06  9:59   ` [PATCH v2 11/20] sigchain: move doc to sigchain.h Heba Waly via GitGitGadget
2019-11-06 22:03     ` Emily Shaffer [this message]
2019-11-11  1:04       ` Heba Waly
2019-11-06  9:59   ` [PATCH v2 12/20] cache: move doc to cache.h Heba Waly via GitGitGadget
2019-11-06 22:04     ` Emily Shaffer
2019-11-06  9:59   ` [PATCH v2 13/20] argv-array: move doc to argv-array.h Heba Waly via GitGitGadget
2019-11-06  9:59   ` [PATCH v2 14/20] credential: move doc to credential.h Heba Waly via GitGitGadget
2019-11-06  9:59   ` [PATCH v2 15/20] parse-options: move doc to parse-options.h Heba Waly via GitGitGadget
2019-11-11  2:45     ` Junio C Hamano
2019-11-11 21:38       ` Heba Waly
2019-11-12  5:57         ` Junio C Hamano
2019-11-15  9:55           ` Heba Waly
2019-11-15 11:37             ` Junio C Hamano
2019-11-15 23:28               ` Emily Shaffer
2019-11-17 11:34                 ` Heba Waly
2019-11-06  9:59   ` [PATCH v2 16/20] run-command: move doc to run-command.h Heba Waly via GitGitGadget
2019-11-06  9:59   ` [PATCH v2 17/20] trace: move doc to trace.h Heba Waly via GitGitGadget
2019-11-07  1:32     ` Emily Shaffer
2019-11-06  9:59   ` [PATCH v2 18/20] tree-walk: move doc to tree-walk.h Heba Waly via GitGitGadget
2019-11-06  9:59   ` [PATCH v2 19/20] submodule-config: move doc to submodule-config.h Heba Waly via GitGitGadget
2019-11-06  9:59   ` [PATCH v2 20/20] trace2: move doc to trace2.h Heba Waly via GitGitGadget
2019-11-11 21:27   ` [PATCH v3 00/21] [Outreachy] Move doc to header files Heba Waly via GitGitGadget
2019-11-11 21:27     ` [PATCH v3 01/21] diff: move doc to diff.h and diffcore.h Heba Waly via GitGitGadget
2019-11-12  7:20       ` Junio C Hamano
2019-11-14 12:22         ` Heba Waly
2019-11-11 21:27     ` [PATCH v3 02/21] dir: move doc to dir.h Heba Waly via GitGitGadget
2019-11-11 21:27     ` [PATCH v3 03/21] graph: move doc to graph.h and graph.c Heba Waly via GitGitGadget
2019-11-11 21:27     ` [PATCH v3 04/21] merge: move doc to ll-merge.h Heba Waly via GitGitGadget
2019-11-11 21:27     ` [PATCH v3 05/21] sha1-array: move doc to sha1-array.h Heba Waly via GitGitGadget
2019-11-11 21:27     ` [PATCH v3 06/21] remote: move doc to remote.h and refspec.h Heba Waly via GitGitGadget
2019-11-11 21:27     ` [PATCH v3 07/21] refs: move doc to refs.h Heba Waly via GitGitGadget
2019-11-11 21:27     ` [PATCH v3 08/21] attr: move doc to attr.h Heba Waly via GitGitGadget
2019-11-11 21:27     ` [PATCH v3 09/21] revision: move doc to revision.h Heba Waly via GitGitGadget
2019-11-11 21:27     ` [PATCH v3 10/21] pathspec: move doc to pathspec.h Heba Waly via GitGitGadget
2019-11-11 21:27     ` [PATCH v3 11/21] sigchain: move doc to sigchain.h Heba Waly via GitGitGadget
2019-11-11 21:27     ` [PATCH v3 12/21] cache: move doc to cache.h Heba Waly via GitGitGadget
2019-11-12  7:05       ` Junio C Hamano
2019-11-14 10:14         ` Heba Waly
2019-11-11 21:27     ` [PATCH v3 13/21] argv-array: move doc to argv-array.h Heba Waly via GitGitGadget
2019-11-11 21:27     ` [PATCH v3 14/21] credential: move doc to credential.h Heba Waly via GitGitGadget
2019-11-11 21:27     ` [PATCH v3 15/21] parse-options: move doc to parse-options.h Heba Waly via GitGitGadget
2019-11-11 21:27     ` [PATCH v3 16/21] run-command: move doc to run-command.h Heba Waly via GitGitGadget
2019-11-11 21:28     ` [PATCH v3 17/21] trace: move doc to trace.h Heba Waly via GitGitGadget
2019-11-11 21:28     ` [PATCH v3 18/21] tree-walk: move doc to tree-walk.h Heba Waly via GitGitGadget
2019-11-11 21:28     ` [PATCH v3 19/21] submodule-config: move doc to submodule-config.h Heba Waly via GitGitGadget
2019-11-11 21:28     ` [PATCH v3 20/21] trace2: move doc to trace2.h Heba Waly via GitGitGadget
2019-11-12  7:02       ` Junio C Hamano
2019-11-14 10:30         ` Heba Waly
2019-11-11 21:28     ` [PATCH v3 21/21] api-index: remove api doc index files Heba Waly via GitGitGadget
2019-11-15  9:53     ` [PATCH v4 00/21] [Outreachy] Move doc to header files Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 01/21] diff: move doc to diff.h and diffcore.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 02/21] dir: move doc to dir.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 03/21] graph: move doc to graph.h and graph.c Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 04/21] merge: move doc to ll-merge.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 05/21] sha1-array: move doc to sha1-array.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 06/21] remote: move doc to remote.h and refspec.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 07/21] refs: move doc to refs.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 08/21] attr: move doc to attr.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 09/21] revision: move doc to revision.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 10/21] pathspec: move doc to pathspec.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 11/21] sigchain: move doc to sigchain.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 12/21] cache: move doc to cache.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 13/21] argv-array: move doc to argv-array.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 14/21] credential: move doc to credential.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 15/21] parse-options: move doc to parse-options.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 16/21] run-command: move doc to run-command.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 17/21] trace: move doc to trace.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 18/21] tree-walk: move doc to tree-walk.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 19/21] submodule-config: move doc to submodule-config.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 20/21] trace2: move doc to trace2.h Heba Waly via GitGitGadget
2019-11-15  9:53       ` [PATCH v4 21/21] api-index: remove api doc index files Heba Waly via GitGitGadget
2019-11-17 21:04       ` [PATCH v5 00/21] [Outreachy] Move doc to header files Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 01/21] diff: move doc to diff.h and diffcore.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 02/21] dir: move doc to dir.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 03/21] graph: move doc to graph.h and graph.c Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 04/21] merge: move doc to ll-merge.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 05/21] sha1-array: move doc to sha1-array.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 06/21] remote: move doc to remote.h and refspec.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 07/21] refs: move doc to refs.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 08/21] attr: move doc to attr.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 09/21] revision: move doc to revision.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 10/21] pathspec: move doc to pathspec.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 11/21] sigchain: move doc to sigchain.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 12/21] cache: move doc to cache.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 13/21] argv-array: move doc to argv-array.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 14/21] credential: move doc to credential.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 15/21] parse-options: add link to doc file in parse-options.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 16/21] run-command: move doc to run-command.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 17/21] trace: move doc to trace.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 18/21] tree-walk: move doc to tree-walk.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 19/21] submodule-config: move doc to submodule-config.h Heba Waly via GitGitGadget
2019-11-17 21:04         ` [PATCH v5 20/21] trace2: move doc to trace2.h Heba Waly via GitGitGadget
2019-11-17 21:05         ` [PATCH v5 21/21] api-index: remove api doc index files Heba Waly via GitGitGadget

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