[PATCH v2] libtracefs: Add trace_sql.bash for tracefs_sql() bash completions

[Steven Rostedt <rostedt@goodmis.org>]

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

trace-cmd and the internal sqlhist programs can take SQL input to be passed
into the tracefs_sql() function. This can be a bit complex, so create a
bash completion script that uses trace-cmd to allow for tab completions on a
bash command line to fill in the next commands.

This should simplify creating bash completions as well as make some
shortcuts known.

Other completions can include this file and use tracefs_sql_completion()
function.

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
Changes since v1: https://lore.kernel.org/all/20250410114740.31b51642@gandalf.local.home/

- Rename the global function to tracefs_sql_completion() for better
  namespace handling.

- Have tracefs_sql_completion() return 0 if it handled the completion
  or 1 if it did not.

 Makefile             |   5 +-
 meson.build          |   1 +
 scripts/utils.mk     |   8 +
 src/meson.build      |   4 +
 src/tracefs_sql.bash | 351 +++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 368 insertions(+), 1 deletion(-)
 create mode 100644 src/tracefs_sql.bash

diff --git a/Makefile b/Makefile
index 6e80226..49a5477 100644
--- a/Makefile
+++ b/Makefile
@@ -300,7 +300,10 @@ install_libs: libs install_pkgconfig
 	$(Q)$(call do_install,$(src)/include/tracefs.h,$(includedir_SQ),644)
 	$(Q)$(call install_ld_config)
 
-install: install_libs
+install_bash_completion: force
+	$(Q)$(call do_install_data,$(src)/src/tracefs_sql.bash,$(BASH_COMPLETE_DIR))
+
+install: install_libs install_bash_completion
 
 install_pkgconfig: $(PKG_CONFIG_FILE)
 	$(Q)$(call , $(PKG_CONFIG_FILE)) \
diff --git a/meson.build b/meson.build
index 2258ca0..04cedb1 100644
--- a/meson.build
+++ b/meson.build
@@ -21,6 +21,7 @@ threads_dep = dependency('threads', required: true)
 cunit_dep = dependency('cunit', required : false)
 
 prefixdir = get_option('prefix')
+datadir = join_paths(prefixdir, get_option('datadir'))
 bindir = join_paths(prefixdir, get_option('bindir'))
 mandir = join_paths(prefixdir, get_option('mandir'))
 htmldir = join_paths(prefixdir, get_option('htmldir'))
diff --git a/scripts/utils.mk b/scripts/utils.mk
index 4d0f8bc..379d47f 100644
--- a/scripts/utils.mk
+++ b/scripts/utils.mk
@@ -187,6 +187,14 @@ define do_install
 	$(INSTALL) $(if $3,-m $3,) $1 '$(DESTDIR_SQ)$2'
 endef
 
+define do_install_data
+	$(print_install)				\
+	if [ ! -d '$(DESTDIR_SQ)$2' ]; then		\
+		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$2';	\
+	fi;						\
+	$(INSTALL) -m 644 $1 '$(DESTDIR_SQ)$2'
+endef
+
 define do_install_pkgconfig_file
 	if [ -n "${pkgconfig_dir}" ]; then 					\
 		$(call do_install,$(PKG_CONFIG_FILE),$(pkgconfig_dir),644); 	\
diff --git a/src/meson.build b/src/meson.build
index 31fd9ed..202df9d 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -63,3 +63,7 @@ pkg.generate(
 libtracefs_dep = declare_dependency(
     include_directories: ['.'],
     link_with: libtracefs)
+
+install_data(
+    'tracefs_sql.bash',
+    install_dir: datadir + '/bash-completion/completions')
diff --git a/src/tracefs_sql.bash b/src/tracefs_sql.bash
new file mode 100644
index 0000000..57a782a
--- /dev/null
+++ b/src/tracefs_sql.bash
@@ -0,0 +1,351 @@
+make_small() {
+    local w=$1
+
+    echo $w | tr A-Z a-z
+}
+
+prev_keyword() {
+    local i=$1
+    shift
+    local words=("$@")
+
+    while [ $i -gt 0 ]; do
+	let i=$i-1
+	local w=`make_small ${words[$i]}`
+
+	case $w in
+	    select)
+		      echo "select"
+		      return
+		      ;;
+		  from)
+		      echo "from"
+		      return
+		      ;;
+		  as)
+		      echo "as"
+		      return
+		      ;;
+		  on)
+		      echo "on"
+		      return
+		      ;;
+		  join)
+		      echo "join"
+		      return
+		      ;;
+		  where)
+		      echo "where"
+		      return
+		      ;;
+		  *)
+		      if [ "$w" != "${w%%,}" ]; then
+			  echo ","
+			  return
+		      fi
+		      if [ "$w" != "${w%%=}" ]; then
+			  echo "="
+			  return
+		      fi
+		      if [ "$w" != "${w%%&}" ]; then
+			  echo "&"
+			  return
+		      fi
+		      ;;
+	    esac
+	done
+	    echo ""
+}
+
+prev_command() {
+    local i=$1
+    shift
+    local words=("$@")
+
+    while [ $i -gt 0 ]; do
+	let i=$i-1
+	local w=`make_small ${words[$i]}`
+
+	case $w in
+	    select)
+		      echo "select"
+		      return
+		      ;;
+		  from)
+		      echo "from"
+		      return
+		      ;;
+		  on)
+		      echo "on"
+		      return
+		      ;;
+		  join)
+		      echo "join"
+		      return
+		      ;;
+		  where)
+		      echo "where"
+		      return
+		      ;;
+	    esac
+	done
+	    echo ""
+}
+
+add_vars() {
+    local words=("$@")
+
+    local i=$COMP_CWORD
+
+    local event=""
+
+    let found_from=0
+    let found_as=0
+
+    while [ $i -gt 0 ]; do
+	let i=$i-1
+	local w=`make_small ${words[$i]}`
+
+	case $w in
+	    "from")
+		let found_from=1
+		;;
+	    "as")
+		# Do not add the event itself if it was used by name
+		if [ $found_as -eq 0 ]; then
+		    event=${words[$i-1]};
+		fi
+		let found_as=1
+		;;
+	    *)
+		if [ $found_from -eq 1 ]; then
+		    start=`echo $w | sed -e 's/\.[^\.]*$//'`
+		    if [ "$start" != "$w" -a "$start" == "${start%%\.*}" -a \
+		         "$start" != "$event" ]; then
+			echo -n "$start "
+		    fi
+		fi
+		;;
+	esac
+    done
+}
+
+add_options() {
+    local cur="$1"
+    local list="$2"
+
+    COMPREPLY=( $(compgen -W "${list}" -- "${cur}") )
+}
+
+print_fields() {
+    local event=$1
+    local var=$2
+    local extra=$3
+
+    local list=`trace-cmd list -e "^${event/\./:}\$" -F |  cut -d';' -f1 | sed -ne 's/\t.*:.* \(.*\)/\1/p' |sed -e 's/\[.*\]//'`
+
+    for field in $list $extra; do
+	if [ -z "$var" ]; then
+	    echo "$event.$field"
+	else
+	    echo "$var.$field"
+	fi
+    done
+}
+
+select_options() {
+    local cur=$1
+    local extra=$2
+    local list=`list_events "${cur/\./:}" | sed -e 's/:/./g'`
+    local select_list=" TIMESTAMP_DELTA TIMESTAMP_DELTA_USECS $extra"
+    local select_fields=" TIMESTAMP TIMESTAMP_USECS STACKTRACE COMM"
+    add_options "$cur" "$list $select_list"
+    local cnt=${#COMPREPLY[@]}
+    if [ $cnt -eq 1 ]; then
+	local comp=${COMPREPLY[0]}
+	local w=$(compgen -W "$select_list" -- "$comp" )
+	if [ -z "$w" ]; then
+	    COMPREPLY=("$comp.")
+	    compopt -o nospace
+	fi
+    elif [ $cnt -eq 0 ]; then
+	local w=`echo $cur | sed -e 's/\.[^\.]*$//'`
+	list=`print_fields $w "" "$select_fields"`
+	COMPREPLY=( $(compgen -W "${list}" -- "${cur}") )
+    fi
+}
+
+check_as() {
+    local words=("$@")
+
+    last_key=`prev_keyword $COMP_CWORD ${words[@]}`
+    if [ "$last_key" != "as" ]; then
+	echo -n "AS"
+    fi
+}
+
+on_list() {
+    local type=$1
+    shift
+    local words=("$@")
+
+    local i=$COMP_CWORD
+
+    local var=""
+
+    while [ $i -gt 0 ]; do
+	let i=$i-1
+	local w=`make_small ${words[$i]}`
+	case $w in
+	    "from"|"join")
+		if [ $w == $type ]; then
+		    print_fields ${words[$i+1]} "$var"
+		    return
+		fi
+		var=""
+		;;
+	    as)
+		var=${words[$i+1]}
+		;;
+	esac
+    done
+}
+
+update_completion() {
+    local cur=$1
+    shift
+    local words=("$@")
+
+    if [ ${#COMPREPLY[@]} -gt 0 ]; then
+	return
+    fi
+
+    for w in ${words[@]}; do
+	if [ "$w" != "${w##$cur}" ]; then
+	    COMPREPLY=("$w")
+	    return
+	fi
+    done
+}
+
+# return 0 if it was handled, otherwise return 1
+tracefs_sql_completion()
+{
+    local prev=$1
+    local cur=$2
+    shift 2
+    local words=("$@")
+
+    if [ "$cur" != "${cur%%,}" ]; then
+	COMPREPLY=("$cur")
+	return 0
+    fi
+
+    local p=`make_small $prev`
+
+    if [ "$p" != "${p%%,}" ]; then
+	p=`prev_command $COMP_CWORD ${words[@]}`
+    fi
+
+    case "$p" in
+	"select")
+	    select_options "$cur"
+	    ;;
+	"on")
+	    list=`on_list "from" ${words[@]}`
+	    add_options "$cur" "$list"
+	    ;;
+	"where")
+	    flist=`on_list "from" ${words[@]}`
+	    jlist=`on_list "join" ${words[@]}`
+	    add_options "$cur" "$flist $jlist"
+	    ;;
+	"as")
+	    local last_cmd=`prev_command $COMP_CWORD ${words[@]}`
+	    case $last_cmd in
+		"select")
+		    if [ ! -z "$cur" ]; then
+			COMPREPLY=("$cur" "$cur,")
+		    fi
+		    ;;
+		"from"|"join")
+		    list=`add_vars ${words[@]}`
+		    if [ ! -z "$list" ]; then
+			add_options "$cur" "$list"
+		    fi
+		    ;;
+	    esac
+	    ;;
+	"from"|"join")
+	    local list=$(trace-cmd list -e "${cur/\./:}" | tr : .)
+	    local prefix=${cur/\./}
+	    if [ -z "$cur" -o  "$cur" != "$prefix" ]; then
+		COMPREPLY=( $(compgen -W "${list}" -- "${cur}") )
+	    else
+		local events=$(for e in $list; do echo ${e/*\./}; done | sort -u)
+	        local systems=$(for s in $list; do echo ${s/\.*/.}; done | sort -u)
+
+		COMPREPLY=( $(compgen -W "all ${events} ${systems}" -- "${cur}") )
+	    fi
+	    ;;
+	# TIMESTAMP_DELTA must be labeled
+	"timestamp_delta"|"timestamp_delta_usecs")
+	    COMPREPLY=( $(compgen -W "AS" -- "${cur}") )
+	    update_completion "$cur" "as"
+	    ;;
+	*)
+	    local last_cmd=`prev_command $COMP_CWORD ${words[@]}`
+	    local list=`check_as ${words[@]}`
+	    local alist=""
+	    if [ ! -z "$list" ]; then
+		alist="as"
+	    fi
+	    case $last_cmd in
+		"select")
+		    if [ "$cur" != "${cur%%,}" ]; then
+			select_options "$cur" "$list"
+		    else
+			add_options "$cur" "FROM , $list"
+			update_completion "$cur" from $alist
+		    fi
+		    ;;
+		"from")
+		    add_options "$cur" "JOIN $list"
+		    update_completion "$cur" join $alist
+		    ;;
+		"join")
+		    add_options "$cur" "ON $list"
+		    update_completion "$cur" on $alist
+		    ;;
+		"on")
+		    if [ "$cur" != "${cur%%=}" ]; then
+			COMPREPLY=("")
+		    else
+			last_key=`prev_keyword $COMP_CWORD ${words[@]}`
+			if [ "$last_key" == "=" ]; then
+			    if [ $prev == "=" ]; then
+				list=`on_list "join" ${words[@]}`
+				add_options "$cur" "$list"
+			    else
+				add_options "$cur" "WHERE"
+				update_completion "$cur" where
+			    fi
+			else
+			    add_options "$cur" "="
+			fi
+		    fi
+		    ;;
+		"where")
+		    if [ "$cur" != "${cur%%[=&]}" ]; then
+			COMPREPLY=("")
+		    else
+			add_options "$cur" "== != &"
+		    fi
+		    ;;
+		*)
+		    return 1
+	    esac
+	    ;;
+    esac
+    return 0
+}
-- 
2.47.2