Start locking

src/g.bash

@@ -12,7 +12,7 @@ export PS4='+(${BASH_SOURCE##*/}:${LINENO}): ${FUNCNAME[0]:+${FUNCNAME[0]}(): }'
 export g__EXISTS=true
 
 g__PATH="${BASH_SOURCE[0]}"
-g__CALLER_PATH="${BASH_SOURCE[1]}"
+g__CALLER_PATH="${BASH_SOURCE[1]:-shell}"
 
 # The global logging level. Lower the number, higher the priority.
 g__LOGGING_LEVEL=2
@@ -64,6 +64,12 @@ g__APP_LAST_ARGPARSE=''
 
 g__APP_LAST_ALIAS=''
 
+g__LOCKING_FILE_DIR="/tmp"
+
+g__LOCKING_NAME_X_DESCRIPTOR=()
+
+g__LOCKING_NEXT_DESCRIPTOR=100
+
 
 ##
 # Initialize the framework
@@ -92,6 +98,8 @@ function g::internals::cleanup() {
 	for file in "${g__FILES_TO_CLEANUP[@]}"; do
 		rm -rf "$file"
 	done
+
+	g::lock::cleanupForExit
 }
 
 
@@ -1982,14 +1990,89 @@ function g::flag::has() {
 	return $(g::app::command::parse::has::flag "$nameOrPosition" "$uuid")
 }
 
-# logging/debug flags
+
+g::log::all  # TODO remove
+
+function g::lock::file() {
+	local callerName="$(basename "$g__CALLER_PATH")"
+	local name="${1:-$callerName}"
+
+	g::internal "Resolving lock file path for name: $name" g::lock
+	g::path::resolve "$g__LOCKING_FILE_DIR" "${name}.lock"
+}
+
+function g::arr::assoc::hasKey() {
+  local key="$1"
+  shift
+  local array="$@"
+
+  for possibleKey in "${!array[@]}"; do
+    if [[ "$key" == "$possibleKey" ]]; then
+      return $(g::util::true)
+    fi
+  done
+
+  return $(g::util::false)
+}
+
+function g::lock::descriptor() {
+	local callerName="$(basename "$g__CALLER_PATH")"
+	local name="${1:-$callerName}"
+	local file="$(g::lock::file "$name")"
+
+	g::internal "Resolving lock file descriptor for file: $file" g::lock
+	if g::arr::assoc::hasKey "$name" "${g__LOCKING_NAME_X_DESCRIPTOR[@]}"; then
+		printf $fd
+		return $(g::util::true)
+	fi
+
+	local fd=$g__LOCKING_NEXT_DESCRIPTOR
+	g__LOCKING_NEXT_DESCRIPTOR=$(($g__LOCKING_NEXT_DESCRIPTOR + 1))
+	g__LOCKING_NAME_X_DESCRIPTOR+=( ["$name"]=$fd )
+
+	g::internal "Mapped FD $fd to lock file: $file" g::lock
+
+	exec $fd>"$file" || return $(g::util::false)
+	printf $fd
+}
+
+function g::lock::acquire() {
+	local callerName="$(basename "$g__CALLER_PATH")"
+	local name="${1:-$callerName}"
+	local descriptor=$(g::lock::descriptor "$name")
+
+	flock $descriptor || g::error::throw "Unable to acquire lock: ${name} (${descriptor})"
+}
+
+function g::lock::try() {
+	local callerName="$(basename "$g__CALLER_PATH")"
+	local name="${1:-$callerName}"
+	local descriptor=$(g::lock::descriptor "$name")
+
+	g::internal "Got descriptor for lock: ${descriptor}"
+
+	flock -n $descriptor || return $(g::util::false)
+	return $(g::util::true)
+}
+
+function g::lock::release() {
+	local callerName="$(basename "$g__CALLER_PATH")"
+	local name="${1:-$callerName}"
+	local file=$(g::lock::file "$name")
+
+	rm -rf "$file"
+}
+
+function g::lock::cleanupForExit() {
+  for file in "${!g__LOCKING_NAME_X_DESCRIPTOR[@]}"; do
+    rm -rf "$file"
+  done
+}
 
 # dependency declarations
 
 # output helpers
 
-# argument parsing
-
 # exception handling
 
 # JSON parsing, INI parsing, rich data types (named parameters & arrays/maps)