Run xmllint validation only once

Before, each documentation target that built something from
postgres.sgml ran xmllint first to validate the input.  Here, we
change it so that the validation only runs once and produces an output
file, and all the other targets build from that output file.  This
avoids redundant work when building multiple documentation targets
(such as html and man).

Also, when we run xmllint, we can resolve entities (included files).
This helps with tools that don't support vpath builds, such as
dbtoepub.

All this also organizes the make targets a bit better for implementing
equivalent steps in meson.

Discussion: https://www.postgresql.org/message-id/e3ae16de-c9f9-f559-2d11-70b1342ae3d1@enterprisedb.com

Author: petere

doc/src/sgml/Makefile

@@ -61,15 +61,22 @@ ALLSGML := $(wildcard $(srcdir)/*.sgml $(srcdir)/ref/*.sgml) $(GENERATED_SGML)
 ALL_IMAGES := $(wildcard $(srcdir)/images/*.svg)
 
 
+# Run validation only once, common to all subsequent targets.  While
+# we're at it, also resolve all entities (that is, copy all included
+# files into one big file).  This helps tools that don't understand
+# vpath builds (such as dbtoepub).
+postgres-full.xml: postgres.sgml $(ALLSGML)
+	$(XMLLINT) $(XMLINCLUDE) --output $@ --noent --valid $<
+
+
 ##
 ## Man pages
 ##
 
 man distprep-man: man-stamp
 
-man-stamp: stylesheet-man.xsl postgres.sgml $(ALLSGML)
-	$(XMLLINT) $(XMLINCLUDE) --noout --valid $(word 2,$^)
-	$(XSLTPROC) $(XMLINCLUDE) $(XSLTPROCFLAGS) $(XSLTPROC_MAN_FLAGS) $(wordlist 1,2,$^)
+man-stamp: stylesheet-man.xsl postgres-full.xml
+	$(XSLTPROC) $(XMLINCLUDE) $(XSLTPROCFLAGS) $(XSLTPROC_MAN_FLAGS) $^
 	touch $@
 
 
@@ -117,7 +124,7 @@ INSTALL.html: %.html : stylesheet-text.xsl %.xml
 	$(XMLLINT) --noout --valid $*.xml
 	$(XSLTPROC) $(XSLTPROCFLAGS) $(XSLTPROC_HTML_FLAGS) $^ >$@
 
-INSTALL.xml: standalone-profile.xsl standalone-install.xml postgres.sgml $(ALLSGML)
+INSTALL.xml: standalone-profile.xsl standalone-install.xml postgres-full.xml
 	$(XSLTPROC) $(XMLINCLUDE) $(XSLTPROCFLAGS) --xinclude $(wordlist 1,2,$^) >$@
 
 
@@ -131,25 +138,22 @@ endif
 
 html: html-stamp
 
-html-stamp: stylesheet.xsl postgres.sgml $(ALLSGML) $(ALL_IMAGES)
-	$(XMLLINT) $(XMLINCLUDE) --noout --valid $(word 2,$^)
+html-stamp: stylesheet.xsl postgres-full.xml $(ALL_IMAGES)
 	$(XSLTPROC) $(XMLINCLUDE) $(XSLTPROCFLAGS) $(XSLTPROC_HTML_FLAGS) $(wordlist 1,2,$^)
 	cp $(ALL_IMAGES) html/
 	cp $(srcdir)/stylesheet.css html/
 	touch $@
 
 htmlhelp: htmlhelp-stamp
 
-htmlhelp-stamp: stylesheet-hh.xsl postgres.sgml $(ALLSGML) $(ALL_IMAGES)
-	$(XMLLINT) $(XMLINCLUDE) --noout --valid $(word 2,$^)
+htmlhelp-stamp: stylesheet-hh.xsl postgres-full.xml $(ALL_IMAGES)
 	$(XSLTPROC) $(XMLINCLUDE) $(XSLTPROCFLAGS) $(wordlist 1,2,$^)
 	cp $(ALL_IMAGES) htmlhelp/
 	cp $(srcdir)/stylesheet.css htmlhelp/
 	touch $@
 
 # single-page HTML
-postgres.html: stylesheet-html-nochunk.xsl postgres.sgml $(ALLSGML) $(ALL_IMAGES)
-	$(XMLLINT) $(XMLINCLUDE) --noout --valid $(word 2,$^)
+postgres.html: stylesheet-html-nochunk.xsl postgres-full.xml $(ALL_IMAGES)
 	$(XSLTPROC) $(XMLINCLUDE) $(XSLTPROCFLAGS) $(XSLTPROC_HTML_FLAGS) -o $@ $(wordlist 1,2,$^)
 
 # single-page text
@@ -166,13 +170,11 @@ postgres.pdf:
 
 XSLTPROC_FO_FLAGS += --stringparam img.src.path '$(srcdir)/'
 
-%-A4.fo: stylesheet-fo.xsl %.sgml $(ALLSGML)
-	$(XMLLINT) $(XMLINCLUDE) --noout --valid $(word 2,$^)
-	$(XSLTPROC) $(XMLINCLUDE) $(XSLTPROCFLAGS) $(XSLTPROC_FO_FLAGS) --stringparam paper.type A4 -o $@ $(wordlist 1,2,$^)
+%-A4.fo: stylesheet-fo.xsl %-full.xml
+	$(XSLTPROC) $(XMLINCLUDE) $(XSLTPROCFLAGS) $(XSLTPROC_FO_FLAGS) --stringparam paper.type A4 -o $@ $^
 
-%-US.fo: stylesheet-fo.xsl %.sgml $(ALLSGML)
-	$(XMLLINT) $(XMLINCLUDE) --noout --valid $(word 2,$^)
-	$(XSLTPROC) $(XMLINCLUDE) $(XSLTPROCFLAGS) $(XSLTPROC_FO_FLAGS) --stringparam paper.type USletter -o $@ $(wordlist 1,2,$^)
+%-US.fo: stylesheet-fo.xsl %-full.xml
+	$(XSLTPROC) $(XMLINCLUDE) $(XSLTPROCFLAGS) $(XSLTPROC_FO_FLAGS) --stringparam paper.type USletter -o $@ $^
 
 %.pdf: %.fo $(ALL_IMAGES)
 	$(FOP) -fo $< -pdf $@
@@ -183,8 +185,11 @@ XSLTPROC_FO_FLAGS += --stringparam img.src.path '$(srcdir)/'
 ##
 
 epub: postgres.epub
-postgres.epub: postgres.sgml $(ALLSGML) $(ALL_IMAGES)
-	$(XMLLINT) --noout --valid $<
+postgres.epub: postgres-full.xml $(ALL_IMAGES)
+ifeq ($(vpath_build),yes)
+	$(MKDIR_P) images
+	cp $(ALL_IMAGES) images/
+endif
 	$(DBTOEPUB) -o $@ $<
 
 
@@ -196,8 +201,7 @@ DB2X_TEXIXML = db2x_texixml
 DB2X_XSLTPROC = db2x_xsltproc
 MAKEINFO = makeinfo
 
-%.texixml: %.sgml $(ALLSGML)
-	$(XMLLINT) --noout --valid $<
+%.texixml: %-full.xml
 	$(DB2X_XSLTPROC) -s texi -g output-file=$(basename $@) $< -o $@
 
 %.texi: %.texixml
@@ -284,6 +288,7 @@ check-tabs:
 # This allows removing some files from the distribution tarballs while
 # keeping the dependencies satisfied.
 .SECONDARY: $(GENERATED_SGML)
+.SECONDARY: postgres-full.xml
 .SECONDARY: INSTALL.html INSTALL.xml
 .SECONDARY: postgres-A4.fo postgres-US.fo
 
@@ -297,6 +302,7 @@ clean:
 	rm -f *.fo *.pdf
 # generated SGML files
 	rm -f $(GENERATED_SGML)
+	rm -f postgres-full.xml
 # HTML Help
 	rm -rf htmlhelp/ htmlhelp-stamp
 # EPUB

doc/src/sgml/standalone-install.xml

@@ -22,10 +22,10 @@ in the stand-alone version.
   C++</productname>, see the main documentation instead.
  </para>
 
- <xi:include href="postgres.sgml" xpointer="install-short" xmlns:xi="http://www.w3.org/2001/XInclude"/>
- <xi:include href="postgres.sgml" xpointer="install-requirements" xmlns:xi="http://www.w3.org/2001/XInclude"/>
- <xi:include href="postgres.sgml" xpointer="install-procedure" xmlns:xi="http://www.w3.org/2001/XInclude"/>
- <xi:include href="postgres.sgml" xpointer="install-post" xmlns:xi="http://www.w3.org/2001/XInclude"/>
+ <xi:include href="postgres-full.xml" xpointer="install-short" xmlns:xi="http://www.w3.org/2001/XInclude"/>
+ <xi:include href="postgres-full.xml" xpointer="install-requirements" xmlns:xi="http://www.w3.org/2001/XInclude"/>
+ <xi:include href="postgres-full.xml" xpointer="install-procedure" xmlns:xi="http://www.w3.org/2001/XInclude"/>
+ <xi:include href="postgres-full.xml" xpointer="install-post" xmlns:xi="http://www.w3.org/2001/XInclude"/>
 
  <sect1 id="install-getting-started">
   <title>Getting Started</title>