ob_get_binary_packages(): Factor out side effects

As described in the documentation, it was only pure after being called
once outside a subshell, but it was never actually called outside a
subshell.  So it rescanned the file system for binary packages every
time.

2 files changed, 41 insertions, 40 deletions

diff --git a/NEWS b/NEWS
index 162fafe..aa1f81c 100644
--- a/NEWS
+++ b/NEWS
@@ -41,6 +41,8 @@ Utilities:
   * Source package names are now prefixed with "src:" instead of "src-".
     pro-archman has supported this in its package name hashing since
     version 2.0.0.
+  * With ob_get_binary_packages() becoming always pure (see below), all
+    utilities now scan the file system for binary packages only once.
 
 libopkbuild:
 
@@ -52,6 +54,10 @@ libopkbuild:
     correctly.
   * New functions ob_validate_section() and ob_qualify_package_name()
     have been added.
+  * ob_get_binary_packages() is now always pure (without side effects
+    that would preclude use in a subshell environment).  Side effects
+    have been factored out into a new internal function called by
+    ob_init_package().
 
 opkbuild version 4.1.4
 ----------------------
diff --git a/lib/package.sh b/lib/package.sh
index da6d688..df129c7 100644
--- a/lib/package.sh
+++ b/lib/package.sh
@@ -21,7 +21,6 @@ _ob_package_dir=
 _ob_package_format_full=
 _ob_package_format=
 _ob_binary_packages=
-_ob_got_binary_packages=false
 _ob_source_parameters=
 _ob_binary_parameters=
 
@@ -35,6 +34,38 @@ _ob_package_do()
 	return 0
 }
 
+_ob_find_binary_packages()
+{
+	local pkgs_clean=
+	local pkg=
+	local pkg_clean=
+
+	pkgs_clean=' '
+	_ob_binary_packages=''
+
+	for pkg in $(_ob_package_do 'get_binary_packages'); do
+		# Validate the name.
+		if ! ob_validate_binary_name "${pkg}"; then
+			_ob_warn_msg 'bad_binary_name' "${pkg}"
+			continue
+		fi
+
+		# Make sure the "clean" name is unique.
+		pkg_clean="$(printf '%s' "${pkg}" | tr 'a-z' 'A-Z' | \
+			tr -C 'A-Z0-9' '_')"
+		case "${pkgs_clean}" in *" ${pkg_clean} "*)
+			_ob_warn_msg 'duplicate_clean_binary_name' \
+				"${pkg_clean}"
+			continue
+		esac
+		pkgs_clean="${pkgs_clean}${pkg_clean} "
+
+		_ob_binary_packages="${_ob_binary_packages} ${pkg}"
+	done
+
+	return 0
+}
+
 ## @brief Initialize libopkbuild for a source package
 ## @details \fBob_init_package\fP() detects the version of and parses all
 ##          metadata of a source package.  This function must be called before
@@ -65,7 +96,7 @@ ob_init_package()
 		return 1
 	fi
 
-	_ob_binary_packages=
+	_ob_find_binary_packages
 
 	_ob_package_do 'parse_package_metadata' || return ${?}
 
@@ -82,19 +113,14 @@ ob_init_package()
 ## @stdout Prints the resulting list of binary packages.
 ## @stderr Prints warning messages on invalid binary package names and duplicate
 ##         "clean" binary package names.
-## @pure maybe This function caches a list of all binary packages to an internal
-##             global variable to save time and avoid repeating warning messages
-##             on subsequent invocations.  It should therefore first be called
-##             outside a subshell, though this is not required.
+## @pure yes This function has no side effects.
 ob_get_binary_packages()
 {
 	local opt=
 	local host_arch=
 	local host_plat=
-	local pkg=
-	local pkgs_clean=
-	local pkg_clean=
 	local pkgs=
+	local pkg=
 
 	OPTIND=1
 	while getopts 'a:p:' opt; do
@@ -112,37 +138,6 @@ ob_get_binary_packages()
 	done
 	shift $((${OPTIND} - 1))
 
-	if ! ${_ob_got_binary_packages}; then
-
-		pkgs_clean=' '
-		_ob_binary_packages=''
-
-		for pkg in $(_ob_package_do 'get_binary_packages'); do
-
-			# Validate the name.
-			if ! ob_validate_binary_name "${pkg}"; then
-				_ob_warn_msg 'bad_binary_name' "${pkg}"
-				continue
-			fi
-
-			# Make sure the "clean" name is unique.
-			pkg_clean="$(printf '%s' "${pkg}" | tr 'a-z' 'A-Z' | \
-				tr -C 'A-Z0-9' '_')"
-			case "${pkgs_clean}" in *" ${pkg_clean} "*)
-				_ob_warn_msg 'duplicate_clean_binary_name' \
-					"${pkg_clean}"
-				continue
-			esac
-			pkgs_clean="${pkgs_clean}${pkg_clean} "
-
-			_ob_binary_packages="${_ob_binary_packages} ${pkg}"
-
-		done
-
-		_ob_got_binary_packages=true
-
-	fi
-
 	pkgs=''
 
 	for pkg in ${_ob_binary_packages}; do