From d5627404e17e12ff6349007efc25fa01db4c9c54 Mon Sep 17 00:00:00 2001
From: "Glenn Y. Rolland" <glenux@glenux.net>
Date: Fri, 23 Jul 2021 16:07:42 +0200
Subject: [PATCH] Improve graphviz

---
 graphviz.mk | 35 ++++++++++++++++++++++-------------
 1 file changed, 22 insertions(+), 13 deletions(-)

diff --git a/graphviz.mk b/graphviz.mk
index 6b34166..8187e0e 100644
--- a/graphviz.mk
+++ b/graphviz.mk
@@ -3,28 +3,28 @@
 ##
 
 ##
-## External variables (API)
+## External variables influencing build process (API)
 ##
-GRAPHVIZ_SRC_DIR=
-GRAPHVIZ_DEST_DIR=
+GRAPHVIZ_SRC_DIR ?=
+GRAPHVIZ_DEST_DIR ?=
 
 ##
 ## Internal variables
 ##
 
 ## Find .dot graphs
-GRAPHVIZ_DOT=$(shell find $(GRAPHVIZ_SRC_DIR) \( -name '*.dot' ! -name '_*' \))
-GRAPHVIZ_DOT_SVG=$(patsubst $(GRAPHVIZ_SRC_DIR)/%.dot,$(GRAPHVIZ_DEST_DIR)/%.dot.svg,$(GRAPHVIZ_DOT))
+GRAPHVIZ_DOT := $(shell find $(GRAPHVIZ_SRC_DIR) \( -name '*.dot' ! -name '_*' \))
+GRAPHVIZ_DOT_SVG := $(patsubst $(GRAPHVIZ_SRC_DIR)/%.dot,$(GRAPHVIZ_DEST_DIR)/%.dot.svg,$(GRAPHVIZ_DOT))
 
 ## Find .circo graphs
-GRAPHVIZ_CIRCO=$(shell find $(GRAPHVIZ_SRC_DIR) \( -name '*.circo' ! -name '_*' \))
-GRAPHVIZ_CIRCO_SVG=$(patsubst $(GRAPHVIZ_SRC_DIR)/%.circo,$(GRAPHVIZ_DEST_DIR)/%.circo.svg,$(GRAPHVIZ_CIRCO))
-GRAPHVIZ_SVG=$(GRAPHVIZ_DOT_SVG) $(GRAPHVIZ_CIRCO_SVG)
+GRAPHVIZ_CIRCO := $(shell find $(GRAPHVIZ_SRC_DIR) \( -name '*.circo' ! -name '_*' \))
+GRAPHVIZ_CIRCO_SVG := $(patsubst $(GRAPHVIZ_SRC_DIR)/%.circo,$(GRAPHVIZ_DEST_DIR)/%.circo.svg,$(GRAPHVIZ_CIRCO))
+GRAPHVIZ_SVG := $(GRAPHVIZ_DOT_SVG) $(GRAPHVIZ_CIRCO_SVG)
 
 ##
 ## Prerequisistes (system packages)
 ##
-GRAPHVIZ_APT_PACKAGES=graphviz
+GRAPHVIZ_APT_PACKAGES := graphviz
 
 ##
 ## Rules
@@ -36,13 +36,22 @@ $(GRAPHVIZ_DEST_DIR)/%.dot.svg: $(GRAPHVIZ_SRC_DIR)/%.dot
 $(GRAPHVIZ_DEST_DIR)/%.circo.svg: $(GRAPHVIZ_SRC_DIR)/%.circo
 	circo -Tsvg $< > $@
 
-graphviz-dot-svg:
+$(GRAPHVIZ_SVG): | $(GRAPHVIZ_DEST_DIR)
+	mkdir -p $(GRAPHVIZ_DEST_DIR)
 
-graphviz-circo-svg:
+graphviz-build-dot-svg: $(GRAPHVIZ_DOT_SVG)
 
-graphviz-svg: graphviz-dot-svg graphviz-circo-svg
+graphviz-build-circo-svg: $(GRAPHVIZ_CIRCO_SVG)
 
+graphviz-build-svg: graphviz-build-dot-svg graphviz-build-circo-svg
+
+graphviz-build: graphviz-build-svg
+
+
+# Clean
+#
 graphviz-clean-svg:
+	rm -f $(GRAPHVIZ_SVG)
 
-graphviz-clean:
+graphviz-clean: graphviz-clean-svg