# By default, `find´ will ignore files which begin with a period and those which are likely to cause problems for `make´.
EXTRAFINDRULES :=
EXTRAFINDINCLUDERULES :=
-FINDRULES := ! '(' '(' -name '[.-]*' -o -name '*[][*?:|$$%\#\\; ]*' -o -name '*[)]' ')' -a -prune ')'$(if $(EXTRAFINDRULES), -a $(EXTRAFINDRULES),)
-FINDINCLUDERULES := $(FINDRULES)$(if $(EXTRAFINDINCLUDERULES), -a $(EXTRAFINDINCLUDERULES),)
+FINDRULES := ! '(' '(' -name '[.-]*' -a ! -name '.' -o -name '*[][*?:|$$%\#\\; ]*' -o -name '*[)]' ')' -a -prune ')'$(if $(EXTRAFINDRULES), -a '(' $(EXTRAFINDRULES) ')',)
+FINDINCLUDERULES := $(FINDRULES)$(if $(EXTRAFINDINCLUDERULES), -a '(' $(EXTRAFINDINCLUDERULES) ')',)
# The list of magic files to use when determining media types.
#
override pathenc = $(subst %2F,/,$(call perenc,$1))
# (overridable) Collect all of the applicable includes from the includes directory.
-sourceincludes := $(shell $(FIND) $(foreach dir,$(INCLUDEDIR),$(call quote,$(dir))) '(' $(FINDRULES) ')' -a -type f)
+sourceincludes := $(if $(and $(INCLUDEDIR),$(wildcard $(INCLUDEDIR))),$(patsubst ./%,%,$(shell $(FIND) $(foreach dir,$(INCLUDEDIR),$(call quote,$(dir))) '(' $(FINDRULES) ')' -a -type f)),)
# (overridable) Collect all of the applicable source files from the source directory, removing any which are also includes.
-sourcefiles := $(filter-out $(sourceincludes),$(shell $(FIND) $(foreach dir,$(SRCDIR),$(call quote,$(dir))) '(' $(FINDRULES) ')' -a -type f))
+sourcefiles := $(if $(and $(SRCDIR),$(wildcard $(SRCDIR))),$(filter-out $(sourceincludes),$(patsubst ./%,%,$(shell $(FIND) $(foreach dir,$(SRCDIR),$(call quote,$(dir))) '(' $(FINDRULES) ')' -a -type f))))
# Figure out the file type of each source file and source include.
ifneq ($(wildcard $(BUILDDIR)/magic.mgc),)
override assetfiles := $(filter-out $(xmlfiles) $(plaintextfiles),$(sourcefiles) $(sourceincludes))
# (callable) Get the types of the given files.
-override typeoffile = $(foreach file,$1,$(patsubst $(file)|%,%,$(filter $(file)|%,$(types))))
+override typeoffile = $(foreach file,$1,$(or $(patsubst $(file)|%,%,$(filter $(file)|%,$(types))),$(error Unable to get type of file `$(file)´)))
# Pair each source magic file with its location in the build directory.
override magicpair := $(foreach magicfile,$(MAGIC),$(magicfile)|$(BUILDDIR)/magic/$(notdir $(magicfile)))
override magicfile = $(foreach file,$1,$(patsubst $(file)|%,%,$(filter $(file)|%,$(magicpair))))
# (callable) Get the local path for the given source file.
-override sourcepath = $(firstword $(foreach directory,$(SRCDIR),$(if $(filter $(directory)/%,$1),$(patsubst $(directory)/%,%,$1),)))
+override sourcepath = $(or $(firstword $(foreach directory,$(SRCDIR),$(if $(filter .,$(directory)),$(wildcard $1),$(if $(filter $(directory)/%,$1),$(patsubst $(directory)/%,%,$1),)))),$(error Unable to get local path for source file `$1´))
# (callable) Get the local path for the given include.
-override includepath = $(firstword $(foreach directory,$(INCLUDEDIR),$(if $(filter $(directory)/%,$1),$(patsubst $(directory)/%,%,$1),)))
+override includepath = $(or $(firstword $(foreach directory,$(INCLUDEDIR),$(if $(filter .,$(directory)),$(wildcard $1),$(if $(filter $(directory)/%,$1),$(patsubst $(directory)/%,%,$1),)))),$(error Unable to get local path for include file `$1´))
# (callable) Get base64 data u·r·i’s for the given files.
#
override fileuripairs := $(join $(patsubst %,%|,$(PARSERS) $(TRANSFORMS) $(call parsed,$(sourcefiles) $(sourceincludes))),$(call pathenc,$(foreach uriable,$(PARSERS) $(TRANSFORMS) $(call parsed,$(sourcefiles) $(sourceincludes)),file://$(abspath $(uriable)))))
# (callable) Get the file u·r·is for the given parsers, transforms, or parsed files.
-override fileuri = $(foreach file,$1,$(patsubst $(file)|%,%,$(filter $(file)|%,$(fileuripairs))))
+override fileuri = $(foreach file,$1,$(or $(patsubst $(file)|%,%,$(filter $(file)|%,$(fileuripairs))),$(error Unable to get file u·r·i for `$(file)´)))
ifneq ($(wildcard $(BUILDDIR)/dependencies),)
# Pair each file with a list of dependencies for it.
override dependencyuris = $(foreach file,$1,$(subst |, ,$(patsubst $(file)|%,%,$(filter $(file)|%,$(dependenciesforfile)))))
# (callable) Get the list of recursive dependencies for the given source files.
+#
+# If the file cannot have dependencies (e·g is an asset file), the resulting value will be the empty string.
override recursives = $(foreach uri,$(filter -%,$(call dependencyuris,$1)),$(call sourcefile,$(patsubst -%,%,$(uri))))
# (callable) Get the list of (nonrecursive) dependencies for the given source files.
+#
+# If the file cannot have dependencies (e·g is an asset file), the resulting value will be the empty string.
override dependencies = $(foreach uri,$(filter-out -%,$(call dependencyuris,$1)),$(call sourcefile,$(uri)))
endif
# Pair source files and their destinations.
override sourcedestinationpair := $(foreach destination,$(destinations),$(call sourcefile,$(firstword $(subst |, ,$(destination))))|$(call perdec,$(subst $(space),|,$(wordlist 2,$(words $(subst |, ,$(destination))),$(subst |, ,$(destination))))))
-# (callable) Get the destination for the given source files.
-override destination = $(foreach file,$1,$(patsubst $(file)|%,%,$(filter $(file)|%,$(sourcedestinationpair))))
+# (callable) Get the destination for the given source files, or return `NOTDEF´.
+#
+# The fallback here is because destinations are used to generate targets and thus must always be non·empty, even when they haven’t been generated yet.
+override destination = $(foreach file,$1,$(or $(patsubst $(file)|%,%,$(filter $(file)|%,$(sourcedestinationpair))),NOTDEF))
# Pair each source file with its compiled location.
override sourcecompiledpair := $(foreach file,$(sourcefiles),$(file)|$(BUILDDIR)/results/$(call destination,$(file)))