From 293e331d69def60110bdc49b6453af905e0509b3 Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicholas.marriott@gmail.com>
Date: Mon, 18 Feb 2013 23:20:21 +0000
Subject: [PATCH] Add functions to allocate and free command contexts rather
 than doing it all on the stack.

---
 cfg.c                | 35 ++++++++++++++++++---------------
 cmd-command-prompt.c | 19 +++++++++---------
 cmd-confirm-before.c | 19 +++++++++---------
 cmd-if-shell.c       | 20 +++++++------------
 cmd-list.c           |  5 +++--
 cmd-run-shell.c      | 22 ++++++++-------------
 cmd.c                | 46 +++++++++++++++++++++++++++++++-------------
 control.c            | 18 +++++++++--------
 key-bindings.c       | 21 ++++++++++----------
 server-client.c      | 25 +++++++++++++-----------
 tmux.h               | 11 +++++++----
 window-choose.c      | 19 +++++++++---------
 12 files changed, 142 insertions(+), 118 deletions(-)

diff --git a/cfg.c b/cfg.c
index c5c8c657..55922299 100644
--- a/cfg.c
+++ b/cfg.c
@@ -80,7 +80,7 @@ load_cfg(const char *path, struct cmd_ctx *ctxin, struct causelist *causes)
 	char		*buf, *copy, *line, *cause;
 	size_t		 len, oldlen;
 	struct cmd_list	*cmdlist;
-	struct cmd_ctx	 ctx;
+	struct cmd_ctx	*ctx;
 	enum cmd_retval	 retval;
 
 	if ((f = fopen(path, "rb")) == NULL) {
@@ -90,6 +90,21 @@ load_cfg(const char *path, struct cmd_ctx *ctxin, struct causelist *causes)
 
 	cfg_references++;
 
+	ctx = cmd_get_ctx();
+	if (ctxin == NULL) {
+		ctx->msgdata = NULL;
+		ctx->curclient = NULL;
+		ctx->cmdclient = NULL;
+	} else {
+		ctx->msgdata = ctxin->msgdata;
+		ctx->curclient = ctxin->curclient;
+		ctx->cmdclient = ctxin->cmdclient;
+	}
+
+	ctx->error = cfg_error;
+	ctx->print = cfg_print;
+	ctx->info = cfg_print;
+
 	n = 0;
 	line = NULL;
 	retval = CMD_RETURN_NORMAL;
@@ -146,22 +161,8 @@ load_cfg(const char *path, struct cmd_ctx *ctxin, struct causelist *causes)
 		if (cmdlist == NULL)
 			continue;
 
-		if (ctxin == NULL) {
-			ctx.msgdata = NULL;
-			ctx.curclient = NULL;
-			ctx.cmdclient = NULL;
-		} else {
-			ctx.msgdata = ctxin->msgdata;
-			ctx.curclient = ctxin->curclient;
-			ctx.cmdclient = ctxin->cmdclient;
-		}
-
-		ctx.error = cfg_error;
-		ctx.print = cfg_print;
-		ctx.info = cfg_print;
-
 		cfg_cause = NULL;
-		switch (cmd_list_exec(cmdlist, &ctx)) {
+		switch (cmd_list_exec(cmdlist, ctx)) {
 		case CMD_RETURN_YIELD:
 			if (retval != CMD_RETURN_ATTACH)
 				retval = CMD_RETURN_YIELD;
@@ -186,6 +187,8 @@ load_cfg(const char *path, struct cmd_ctx *ctxin, struct causelist *causes)
 	}
 	fclose(f);
 
+	cmd_free_ctx(ctx);
+
 	cfg_references--;
 
 	return (retval);
diff --git a/cmd-command-prompt.c b/cmd-command-prompt.c
index ea380353..2a0e1aa7 100644
--- a/cmd-command-prompt.c
+++ b/cmd-command-prompt.c
@@ -150,7 +150,7 @@ cmd_command_prompt_callback(void *data, const char *s)
 	struct cmd_command_prompt_cdata	*cdata = data;
 	struct client			*c = cdata->c;
 	struct cmd_list			*cmdlist;
-	struct cmd_ctx			 ctx;
+	struct cmd_ctx			*ctx;
 	char				*cause, *new_template, *prompt, *ptr;
 	char				*input = NULL;
 
@@ -184,17 +184,18 @@ cmd_command_prompt_callback(void *data, const char *s)
 		return (0);
 	}
 
-	ctx.msgdata = NULL;
-	ctx.curclient = c;
+	ctx = cmd_get_ctx();
+	ctx->msgdata = NULL;
+	ctx->curclient = c;
+	ctx->cmdclient = NULL;
 
-	ctx.error = key_bindings_error;
-	ctx.print = key_bindings_print;
-	ctx.info = key_bindings_info;
+	ctx->error = key_bindings_error;
+	ctx->print = key_bindings_print;
+	ctx->info = key_bindings_info;
 
-	ctx.cmdclient = NULL;
-
-	cmd_list_exec(cmdlist, &ctx);
+	cmd_list_exec(cmdlist, ctx);
 	cmd_list_free(cmdlist);
+	cmd_free_ctx(ctx);
 
 	if (c->prompt_callbackfn != (void *) &cmd_command_prompt_callback)
 		return (1);
diff --git a/cmd-confirm-before.c b/cmd-confirm-before.c
index 329027cc..33733c33 100644
--- a/cmd-confirm-before.c
+++ b/cmd-confirm-before.c
@@ -108,7 +108,7 @@ cmd_confirm_before_callback(void *data, const char *s)
 	struct cmd_confirm_before_data	*cdata = data;
 	struct client			*c = cdata->c;
 	struct cmd_list			*cmdlist;
-	struct cmd_ctx	 	 	 ctx;
+	struct cmd_ctx	 	 	*ctx;
 	char				*cause;
 
 	if (s == NULL || *s == '\0')
@@ -125,17 +125,18 @@ cmd_confirm_before_callback(void *data, const char *s)
 		return (0);
 	}
 
-	ctx.msgdata = NULL;
-	ctx.curclient = c;
+	ctx = cmd_get_ctx();
+	ctx->msgdata = NULL;
+	ctx->curclient = c;
+	ctx->cmdclient = NULL;
 
-	ctx.error = key_bindings_error;
-	ctx.print = key_bindings_print;
-	ctx.info = key_bindings_info;
+	ctx->error = key_bindings_error;
+	ctx->print = key_bindings_print;
+	ctx->info = key_bindings_info;
 
-	ctx.cmdclient = NULL;
-
-	cmd_list_exec(cmdlist, &ctx);
+	cmd_list_exec(cmdlist, ctx);
 	cmd_list_free(cmdlist);
+	cmd_free_ctx(ctx);
 
 	return (0);
 }
diff --git a/cmd-if-shell.c b/cmd-if-shell.c
index 636cf805..6f0b151a 100644
--- a/cmd-if-shell.c
+++ b/cmd-if-shell.c
@@ -47,7 +47,7 @@ const struct cmd_entry cmd_if_shell_entry = {
 struct cmd_if_shell_data {
 	char		*cmd_if;
 	char		*cmd_else;
-	struct cmd_ctx	 ctx;
+	struct cmd_ctx	*ctx;
 };
 
 enum cmd_retval
@@ -63,12 +63,9 @@ cmd_if_shell_exec(struct cmd *self, struct cmd_ctx *ctx)
 		cdata->cmd_else = xstrdup(args->argv[2]);
 	else
 		cdata->cmd_else = NULL;
-	memcpy(&cdata->ctx, ctx, sizeof cdata->ctx);
 
-	if (ctx->cmdclient != NULL)
-		ctx->cmdclient->references++;
-	if (ctx->curclient != NULL)
-		ctx->curclient->references++;
+	cdata->ctx = ctx;
+	cmd_ref_ctx(ctx);
 
 	job_run(shellcmd, cmd_if_shell_callback, cmd_if_shell_free, cdata);
 
@@ -79,7 +76,7 @@ void
 cmd_if_shell_callback(struct job *job)
 {
 	struct cmd_if_shell_data	*cdata = job->data;
-	struct cmd_ctx			*ctx = &cdata->ctx;
+	struct cmd_ctx			*ctx = cdata->ctx;
 	struct cmd_list			*cmdlist;
 	char				*cause, *cmd;
 
@@ -105,14 +102,11 @@ void
 cmd_if_shell_free(void *data)
 {
 	struct cmd_if_shell_data	*cdata = data;
-	struct cmd_ctx			*ctx = &cdata->ctx;
+	struct cmd_ctx			*ctx = cdata->ctx;
 
-	if (ctx->cmdclient != NULL) {
-		ctx->cmdclient->references--;
+	if (ctx->cmdclient != NULL)
 		ctx->cmdclient->flags |= CLIENT_EXIT;
-	}
-	if (ctx->curclient != NULL)
-		ctx->curclient->references--;
+	cmd_free_ctx(ctx);
 
 	free(cdata->cmd_else);
 	free(cdata->cmd_if);
diff --git a/cmd-list.c b/cmd-list.c
index 1717ec3b..6820d007 100644
--- a/cmd-list.c
+++ b/cmd-list.c
@@ -97,7 +97,7 @@ cmd_list_exec(struct cmd_list *cmdlist, struct cmd_ctx *ctx)
 	TAILQ_FOREACH(cmd, &cmdlist->list, qentry) {
 		if (guards)
 			ctx->print(ctx, "%%begin");
-		n = cmd_exec(cmd, ctx);
+		n = cmd->entry->exec(cmd, ctx);
 		if (guards)
 			ctx->print(ctx, "%%end");
 
@@ -146,7 +146,8 @@ cmd_list_free(struct cmd_list *cmdlist)
 	while (!TAILQ_EMPTY(&cmdlist->list)) {
 		cmd = TAILQ_FIRST(&cmdlist->list);
 		TAILQ_REMOVE(&cmdlist->list, cmd, qentry);
-		cmd_free(cmd);
+		args_free(cmd->args);
+		free(cmd);
 	}
 	free(cmdlist);
 }
diff --git a/cmd-run-shell.c b/cmd-run-shell.c
index 44e796df..03cbc292 100644
--- a/cmd-run-shell.c
+++ b/cmd-run-shell.c
@@ -47,7 +47,7 @@ const struct cmd_entry cmd_run_shell_entry = {
 
 struct cmd_run_shell_data {
 	char		*cmd;
-	struct cmd_ctx	 ctx;
+	struct cmd_ctx	*ctx;
 	u_int		 wp_id;
 };
 
@@ -55,7 +55,7 @@ void
 cmd_run_shell_print(struct job *job, const char *msg)
 {
 	struct cmd_run_shell_data	*cdata = job->data;
-	struct cmd_ctx			*ctx = &cdata->ctx;
+	struct cmd_ctx			*ctx = cdata->ctx;
 	struct window_pane		*wp;
 
 	wp = window_pane_find_by_id(cdata->wp_id);
@@ -84,12 +84,9 @@ cmd_run_shell_exec(struct cmd *self, struct cmd_ctx *ctx)
 	cdata = xmalloc(sizeof *cdata);
 	cdata->cmd = xstrdup(args->argv[0]);
 	cdata->wp_id = wp->id;
-	memcpy(&cdata->ctx, ctx, sizeof cdata->ctx);
 
-	if (ctx->cmdclient != NULL)
-		ctx->cmdclient->references++;
-	if (ctx->curclient != NULL)
-		ctx->curclient->references++;
+	cdata->ctx = ctx;
+	cmd_ref_ctx(ctx);
 
 	job_run(shellcmd, cmd_run_shell_callback, cmd_run_shell_free, cdata);
 
@@ -100,7 +97,7 @@ void
 cmd_run_shell_callback(struct job *job)
 {
 	struct cmd_run_shell_data	*cdata = job->data;
-	struct cmd_ctx			*ctx = &cdata->ctx;
+	struct cmd_ctx			*ctx = cdata->ctx;
 	char				*cmd, *msg, *line;
 	size_t				 size;
 	int				 retcode;
@@ -154,14 +151,11 @@ void
 cmd_run_shell_free(void *data)
 {
 	struct cmd_run_shell_data	*cdata = data;
-	struct cmd_ctx			*ctx = &cdata->ctx;
+	struct cmd_ctx			*ctx = cdata->ctx;
 
-	if (ctx->cmdclient != NULL) {
-		ctx->cmdclient->references--;
+	if (ctx->cmdclient != NULL)
 		ctx->cmdclient->flags |= CLIENT_EXIT;
-	}
-	if (ctx->curclient != NULL)
-		ctx->curclient->references--;
+	cmd_free_ctx(ctx);
 
 	free(cdata->cmd);
 	free(cdata);
diff --git a/cmd.c b/cmd.c
index 52c1a303..23e86cff 100644
--- a/cmd.c
+++ b/cmd.c
@@ -132,6 +132,39 @@ struct winlink	*cmd_find_window_offset(const char *, struct session *, int *);
 int		 cmd_find_index_offset(const char *, struct session *, int *);
 struct window_pane *cmd_find_pane_offset(const char *, struct winlink *);
 
+struct cmd_ctx *
+cmd_get_ctx(void)
+{
+	struct cmd_ctx	*ctx;
+
+	ctx = xcalloc(1, sizeof *ctx);
+	ctx->references = 0;
+
+	cmd_ref_ctx(ctx);
+	return (ctx);
+}
+
+void
+cmd_free_ctx(struct cmd_ctx *ctx)
+{
+	if (ctx->cmdclient != NULL)
+		ctx->cmdclient->references--;
+	if (ctx->curclient != NULL)
+		ctx->curclient->references--;
+	if (--ctx->references == 0)
+		free(ctx);
+}
+
+void
+cmd_ref_ctx(struct cmd_ctx *ctx)
+{
+	ctx->references++;
+	if (ctx->cmdclient != NULL)
+		ctx->cmdclient->references++;
+	if (ctx->curclient != NULL)
+		ctx->curclient->references++;
+}
+
 int
 cmd_pack_argv(int argc, char **argv, char *buf, size_t len)
 {
@@ -281,19 +314,6 @@ usage:
 	return (NULL);
 }
 
-enum cmd_retval
-cmd_exec(struct cmd *cmd, struct cmd_ctx *ctx)
-{
-	return (cmd->entry->exec(cmd, ctx));
-}
-
-void
-cmd_free(struct cmd *cmd)
-{
-	args_free(cmd->args);
-	free(cmd);
-}
-
 size_t
 cmd_print(struct cmd *cmd, char *buf, size_t len)
 {
diff --git a/control.c b/control.c
index b5ec6bdb..f00f57f9 100644
--- a/control.c
+++ b/control.c
@@ -93,7 +93,7 @@ void
 control_callback(struct client *c, int closed, unused void *data)
 {
 	char		*line, *cause;
-	struct cmd_ctx	 ctx;
+	struct cmd_ctx	*ctx;
 	struct cmd_list	*cmdlist;
 
 	if (closed)
@@ -108,22 +108,24 @@ control_callback(struct client *c, int closed, unused void *data)
 			break;
 		}
 
-		ctx.msgdata = NULL;
-		ctx.cmdclient = NULL;
-		ctx.curclient = c;
+		ctx = cmd_get_ctx();
+		ctx->msgdata = NULL;
+		ctx->cmdclient = NULL;
+		ctx->curclient = c;
 
-		ctx.error = control_msg_error;
-		ctx.print = control_msg_print;
-		ctx.info = control_msg_info;
+		ctx->error = control_msg_error;
+		ctx->print = control_msg_print;
+		ctx->info = control_msg_info;
 
 		if (cmd_string_parse(line, &cmdlist, &cause) != 0) {
 			control_write(c, "%%error in line \"%s\": %s", line,
 			    cause);
 			free(cause);
 		} else {
-			cmd_list_exec(cmdlist, &ctx);
+			cmd_list_exec(cmdlist, ctx);
 			cmd_list_free(cmdlist);
 		}
+		cmd_free_ctx(ctx);
 
 		free(line);
 	}
diff --git a/key-bindings.c b/key-bindings.c
index cf5237d4..a25d3700 100644
--- a/key-bindings.c
+++ b/key-bindings.c
@@ -262,18 +262,18 @@ key_bindings_info(struct cmd_ctx *ctx, const char *fmt, ...)
 void
 key_bindings_dispatch(struct key_binding *bd, struct client *c)
 {
-	struct cmd_ctx	 ctx;
+	struct cmd_ctx	*ctx;
 	struct cmd	*cmd;
 	int		 readonly;
 
-	ctx.msgdata = NULL;
-	ctx.curclient = c;
+	ctx = cmd_get_ctx();
+	ctx->msgdata = NULL;
+	ctx->cmdclient = NULL;
+	ctx->curclient = c;
 
-	ctx.error = key_bindings_error;
-	ctx.print = key_bindings_print;
-	ctx.info = key_bindings_info;
-
-	ctx.cmdclient = NULL;
+	ctx->error = key_bindings_error;
+	ctx->print = key_bindings_print;
+	ctx->info = key_bindings_info;
 
 	readonly = 1;
 	TAILQ_FOREACH(cmd, &bd->cmdlist->list, qentry) {
@@ -281,9 +281,10 @@ key_bindings_dispatch(struct key_binding *bd, struct client *c)
 			readonly = 0;
 	}
 	if (!readonly && c->flags & CLIENT_READONLY) {
-		key_bindings_info(&ctx, "Client is read-only");
+		key_bindings_info(ctx, "client is read-only");
 		return;
 	}
 
-	cmd_list_exec(bd->cmdlist, &ctx);
+	cmd_list_exec(bd->cmdlist, ctx);
+	cmd_free_ctx(ctx);
 }
diff --git a/server-client.c b/server-client.c
index d4449a50..1500419c 100644
--- a/server-client.c
+++ b/server-client.c
@@ -864,24 +864,24 @@ server_client_msg_info(struct cmd_ctx *ctx, const char *fmt, ...)
 void
 server_client_msg_command(struct client *c, struct msg_command_data *data)
 {
-	struct cmd_ctx	 ctx;
+	struct cmd_ctx	*ctx;
 	struct cmd_list	*cmdlist = NULL;
 	int		 argc;
 	char	       **argv, *cause;
 
-	ctx.error = server_client_msg_error;
-	ctx.print = server_client_msg_print;
-	ctx.info = server_client_msg_info;
+	ctx = cmd_get_ctx();
+	ctx->msgdata = data;
+	ctx->curclient = NULL;
+	ctx->cmdclient = c;
 
-	ctx.msgdata = data;
-	ctx.curclient = NULL;
-
-	ctx.cmdclient = c;
+	ctx->error = server_client_msg_error;
+	ctx->print = server_client_msg_print;
+	ctx->info = server_client_msg_info;
 
 	argc = data->argc;
 	data->argv[(sizeof data->argv) - 1] = '\0';
 	if (cmd_unpack_argv(data->argv, sizeof data->argv, argc, &argv) != 0) {
-		server_client_msg_error(&ctx, "command too long");
+		server_client_msg_error(ctx, "command too long");
 		goto error;
 	}
 
@@ -892,13 +892,13 @@ server_client_msg_command(struct client *c, struct msg_command_data *data)
 	}
 
 	if ((cmdlist = cmd_list_parse(argc, argv, &cause)) == NULL) {
-		server_client_msg_error(&ctx, "%s", cause);
+		server_client_msg_error(ctx, "%s", cause);
 		cmd_free_argv(argc, argv);
 		goto error;
 	}
 	cmd_free_argv(argc, argv);
 
-	switch (cmd_list_exec(cmdlist, &ctx))
+	switch (cmd_list_exec(cmdlist, ctx))
 	{
 	case CMD_RETURN_ERROR:
 	case CMD_RETURN_NORMAL:
@@ -909,11 +909,14 @@ server_client_msg_command(struct client *c, struct msg_command_data *data)
 		break;
 	}
 	cmd_list_free(cmdlist);
+	cmd_free_ctx(ctx);
 	return;
 
 error:
 	if (cmdlist != NULL)
 		cmd_list_free(cmdlist);
+	cmd_free_ctx(ctx);
+
 	c->flags |= CLIENT_EXIT;
 }
 
diff --git a/tmux.h b/tmux.h
index d602b145..df47cdb3 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1362,8 +1362,10 @@ struct cmd_ctx {
 	 * cmdclient and curclient may both be NULL if the command is in the
 	 * configuration file.
 	 */
-	struct client  *curclient;
-	struct client  *cmdclient;
+	struct client		*curclient;
+	struct client		*cmdclient;
+
+	int			 references;
 
 	struct msg_command_data	*msgdata;
 
@@ -1710,13 +1712,14 @@ long long	 args_strtonum(
 		    struct args *, u_char, long long, long long, char **);
 
 /* cmd.c */
+struct cmd_ctx	*cmd_get_ctx(void);
+void		 cmd_free_ctx(struct cmd_ctx *);
+void		 cmd_ref_ctx(struct cmd_ctx *);
 int		 cmd_pack_argv(int, char **, char *, size_t);
 int		 cmd_unpack_argv(char *, size_t, int, char ***);
 char	       **cmd_copy_argv(int, char *const *);
 void		 cmd_free_argv(int, char **);
 struct cmd	*cmd_parse(int, char **, char **);
-enum cmd_retval	 cmd_exec(struct cmd *, struct cmd_ctx *);
-void		 cmd_free(struct cmd *);
 size_t		 cmd_print(struct cmd *, char *, size_t);
 struct session	*cmd_current_session(struct cmd_ctx *, int);
 struct client	*cmd_current_client(struct cmd_ctx *);
diff --git a/window-choose.c b/window-choose.c
index d37527de..e48db7e5 100644
--- a/window-choose.c
+++ b/window-choose.c
@@ -200,7 +200,7 @@ window_choose_data_free(struct window_choose_data *wcd)
 void
 window_choose_data_run(struct window_choose_data *cdata)
 {
-	struct cmd_ctx		 ctx;
+	struct cmd_ctx		*ctx;
 	struct cmd_list		*cmdlist;
 	char			*cause;
 
@@ -220,17 +220,18 @@ window_choose_data_run(struct window_choose_data *cdata)
 		return;
 	}
 
-	ctx.msgdata = NULL;
-	ctx.curclient = cdata->start_client;
+	ctx = cmd_get_ctx();
+	ctx->msgdata = NULL;
+	ctx->curclient = cdata->start_client;
+	ctx->cmdclient = NULL;
 
-	ctx.error = key_bindings_error;
-	ctx.print = key_bindings_print;
-	ctx.info = key_bindings_info;
+	ctx->error = key_bindings_error;
+	ctx->print = key_bindings_print;
+	ctx->info = key_bindings_info;
 
-	ctx.cmdclient = NULL;
-
-	cmd_list_exec(cmdlist, &ctx);
+	cmd_list_exec(cmdlist, ctx);
 	cmd_list_free(cmdlist);
+	cmd_free_ctx(ctx);
 }
 
 void