Add APIs for external precmd/preexec integrations

Author: akinomyoga

bash-preexec.sh

@@ -62,6 +62,9 @@ __bp_inside_preexec=0
 # Initial PROMPT_COMMAND string that is removed from PROMPT_COMMAND post __bp_install
 __bp_install_string=$'__bp_trap_string="$(trap -p DEBUG)"\ntrap - DEBUG\n__bp_install'
 
+# The command string that is registered to the DEBUG trap.
+__bp_trapdebug_string='__bp_preexec_invoke_exec "$_"'
+
 # Fails if any of the given variables are readonly
 # Reference https://stackoverflow.com/a/4441178
 __bp_require_not_readonly() {
@@ -143,15 +146,19 @@ __bp_precmd_invoke_cmd() {
       return
     fi
     local __bp_inside_precmd=1
+    __bp_invoke_precmd_functions "$__bp_last_ret_value" "$__bp_last_argument_prev_command"
+}
 
+__bp_invoke_precmd_functions() {
+    local __lastexit=$1 __lastarg=$2
     # Invoke every function defined in our function array.
     local precmd_function
     for precmd_function in "${precmd_functions[@]}"; do
 
         # Only execute this function if it actually exists.
         # Test existence of functions with: declare -[Ff]
         if type -t "$precmd_function" 1>/dev/null; then
-            __bp_set_ret_value "$__bp_last_ret_value" "$__bp_last_argument_prev_command"
+            __bp_set_ret_value "$__lastexit" "$__lastarg"
             # Quote our function invocation to prevent issues with IFS
             "$precmd_function"
         fi
@@ -244,32 +251,40 @@ __bp_preexec_invoke_exec() {
         return
     fi
 
-    # Invoke every function defined in our function array.
+    local preexec_ret_value
+    __bp_invoke_preexec_functions "${__bp_last_ret_value:-}" "$__bp_last_argument_prev_command" "$this_command"
+
+    # Restore the last argument of the last executed command, and set the return
+    # value of the DEBUG trap to be the return code of the last preexec function
+    # to return an error.
+    # If `extdebug` is enabled a non-zero return value from any preexec function
+    # will cause the user's command not to execute.
+    # Run `shopt -s extdebug` to enable
+    __bp_set_ret_value "$preexec_ret_value" "$__bp_last_argument_prev_command"
+}
+
+# This function invokes every function defined in our function array.  This
+# function assigns the last error exit status to the variable
+# `preexec_ret_value`.  If there is no error, preexec_ret_value is set to `0`.
+__bp_invoke_preexec_functions() {
+    local __lastexit=$1 __lastarg=$2 __this_command=$3
     local preexec_function
     local preexec_function_ret_value
-    local preexec_ret_value=0
+    preexec_ret_value=0
     for preexec_function in "${preexec_functions[@]:-}"; do
 
         # Only execute each function if it actually exists.
         # Test existence of function with: declare -[fF]
         if type -t "$preexec_function" 1>/dev/null; then
-            __bp_set_ret_value ${__bp_last_ret_value:-}
+            __bp_set_ret_value "$__lastexit" "$__lastarg"
             # Quote our function invocation to prevent issues with IFS
-            "$preexec_function" "$this_command"
+            "$preexec_function" "$__this_command"
             preexec_function_ret_value="$?"
             if [[ "$preexec_function_ret_value" != 0 ]]; then
                 preexec_ret_value="$preexec_function_ret_value"
             fi
         fi
     done
-
-    # Restore the last argument of the last executed command, and set the return
-    # value of the DEBUG trap to be the return code of the last preexec function
-    # to return an error.
-    # If `extdebug` is enabled a non-zero return value from any preexec function
-    # will cause the user's command not to execute.
-    # Run `shopt -s extdebug` to enable
-    __bp_set_ret_value "$preexec_ret_value" "$__bp_last_argument_prev_command"
 }
 
 __bp_install() {
@@ -278,7 +293,7 @@ __bp_install() {
         return 1;
     fi
 
-    trap '__bp_preexec_invoke_exec "$_"' DEBUG
+    trap "$__bp_trapdebug_string" DEBUG
 
     # Preserve any prior DEBUG trap as a preexec function
     local prior_trap=$(sed "s/[^']*'\(.*\)'[^']*/\1/" <<<"${__bp_trap_string:-}")
@@ -319,10 +334,13 @@ __bp_install() {
     fi;
     PROMPT_COMMAND+='__bp_interactive_mode'
 
-    # Add two functions to our arrays for convenience
-    # of definition.
-    precmd_functions+=(precmd)
-    preexec_functions+=(preexec)
+    # Add two functions to our arrays for convenience of definition only when
+    # the functions have not yet added.
+    if [[ ! ${__bp_installed_convenience_functions-} ]]; then
+        __bp_installed_convenience_functions=1
+        precmd_functions+=(precmd)
+        preexec_functions+=(preexec)
+    fi
 
     # Invoke our two functions manually that were added to $PROMPT_COMMAND
     __bp_precmd_invoke_cmd
@@ -345,6 +363,29 @@ __bp_install_after_session_init() {
     PROMPT_COMMAND+=${__bp_install_string}
 }
 
+__bp_uninstall() {
+    # Remove __bp_install hook from PROMPT_COMMAND
+    if [[ ${PROMPT_COMMAND-} == *"$__bp_install_string"* ]]; then
+        PROMPT_COMMAND="${PROMPT_COMMAND//$__bp_install_string[;$'\n']}" # Edge case of appending to PROMPT_COMMAND
+        PROMPT_COMMAND="${PROMPT_COMMAND//$__bp_install_string}"
+    fi
+
+    # Remove precmd hook from PROMPT_COMMAND
+    PROMPT_COMMAND=${PROMPT_COMMAND/#$'__bp_precmd_invoke_cmd\n'/$'\n'}
+    PROMPT_COMMAND=${PROMPT_COMMAND%$'\n__bp_interactive_mode'}
+    PROMPT_COMMAND=${PROMPT_COMMAND#$'\n'}
+
+    # Remove preexec hook in the DEBUG trap
+    local q="'" Q="'\''"
+    if [[ $(trap -p DEBUG) == "trap -- '${__bp_trapdebug_string//$q/$Q}' DEBUG" ]]; then
+        if [[ ${__bp_trap_string-} ]]; then
+            eval -- "$__bp_trap_string"
+        else
+            trap - DEBUG
+        fi
+    fi
+}
+
 # Run our install so long as we're not delaying it.
 if [[ -z "${__bp_delay_install:-}" ]]; then
     __bp_install_after_session_init