Remove stat dependency

This is, strictly speaking, a downgrade in functionality, with the
upside of reducing reliance on non·Posix programs (namely `stat`). A
better, Posix‐compliant solution is to archive an empty file with the
correct modification time and then list out the time from that archive;
however, as far as I’m aware, it’s not possible to obtain an
implementation of the `pax` utility which actually supports this. macOS
only supports a very limited subset of the `listopt` option, and only
for pax archives (not tarballs); other implementations don’t seem to
support it at all.

diff --git a/GNUmakefile b/GNUmakefile
index 0156970c9b352fa5c7e62430e7ac6beec527f627..73c8057e8782297050b42056ed031b63ab3db9d8 100644 (file)
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -36,7 +36,6 @@ override define makefileinfo
 ║│ • rm                                                       │║
 ║│ • sed                                                      │║
 ║│ • sleep                                                    │║
-║│ • stat                                                     │║
 ║│ • test                                                     │║
 ║│ • touch                                                    │║
 ║│ • tr                                                       │║
@@ -117,7 +116,6 @@ PRINTF := printf
 RM := rm
 SED := sed
 SLEEP := sleep
-STAT := stat
 TEST := test
 TOUCH := touch
 TR := tr
@@ -257,10 +255,17 @@ override silent := $(if $(VERBOSE),,@)
 
 # (callable) Get the modified time of the provided file.
 #
-# This is messy; there is no portable way of using `stat´.
+# Only the date·time information available via `ls -l´ is supported; that is, only minute precision for files newer than six months, and only day precision for files which are older.
+# This is, unfortunately, the best that can be done in pure Posix as of now.
+#
+# There is an easier implementation which provides the full date·time by archiving an empty file and then reading it back out of the archive :—
+#
+#     $(shell LC_TIME=POSIX TZ=UTC0 $(TOUCH) -m -r $(callquote,$1) $(BUILDDIR)/.mtime && $(PAX) -w -x ustar $(BUILDDIR)/.mtime | $(PAX) -v -o 'listopt=%(mtime=%Y-%m-%dT%H:%M:%SZ)T')
+#
+# However, it depends on the `listopt´ option in `pax´, which (despite being specified in Posix) no implementations actually support.
 #
 # ☡ This variable creates a subshell every time it is computed.
-override modtime = $(shell if $(STAT) --version 2> /dev/null | $(GREP) -q GNU; then $(DATE) -u -d "@$$(TZ= $(STAT) -c '%Y' $(call quote,$1))" '+%Y-%m-%dT%H:%M:%SZ'; else TZ= $(STAT) -f '%Sm' -t '%Y-%m-%dT%H:%M:%SZ' $(call quote,$1); fi)
+override modtime = $(shell { $(DATE) -u '+%Y-%m'; LC_TIME=POSIX TZ=UTC0 ls -q -A -l $(call quote,$1) | $(SED) 's/\([^ ]* \{1,\}\)\{5\}\(\([^ ]* \{1,\}\)\{3\}\).*/\2/;s/ \([0123456789]\) / 0\1 /;s/Jan/01/;s/Feb/02/;s/Mar/03/;s/Apr/04/;s/May/05/;s/Jun/06/;s/Jul/07/;s/Aug/08/;s/Sep/09/;s/Oct/10/;s/Nov/11/;s/Dec/12/;s/\([0123456789]\{2\}\) *\([0123456789]\{2\}\) *\([0123456789]\{4\}\)/\3-\1-\2T00:00:00Z/;s/\([0123456789]\{2\}\) *\([0123456789]\{2\}\) *\([0123456789:]\{5\}\)/XXXX-\1-\2T\3:00Z/'; } | $(TR) -d ' ' | $(AWK) -F '-' 'NR==1{year=$$1;month=$$2}$$1=="XXXX"&&$$2<=month{print year"-"$$2"-"$$3}$$1=="XXXX"&&$$2>month{print year-1"-"$$2"-"$$3}NR>1&&$$1!="XXXX"')
 
 # ─ ¶ Recipe Variable Definitions ─────────────────────────────────────
 
@@ -502,7 +507,7 @@ install : $(call installed,$(recursivefiles) $(installablefiles)) ;
 
 # List all source files and includes and their computed types.
 list :
-       @$(PRINTF) '%b' $(call quote,$(foreach file,$(sort $(sourcefiles)) $(sort $(sourceincludes)),\0033[1m$(file)\0033[22m|$(call typeoffile,$(file))|[\0033[3m$(if $(filter $(file),$(xmlfiles)),xml,$(if $(filter $(file),$(plaintextfiles)),text,asset))$(if $(filter $(file),$(sourceincludes)),|include,)\0033[23m]$(if $(call dependencies,$(file))$(call recursives,$(file)), $(strip $(foreach recursive,$(call recursives,$(file)),\0033[93;41m•|Recursive|Dependency|\0033[39;49m|$(recursive)) $(foreach dependency,$(call dependencies,$(file)),\0033[2m•|Dependency|\0033[22m|$(dependency))))$(if $(filter $(file),$(sourcefiles)), →|<\0033[4m/$(call destination,$(file))\0033[24m>,) )) | $(TR) ' |' '\n '
+       @$(PRINTF) '%b' $(call quote,$(foreach file,$(sort $(sourcefiles)) $(sort $(sourceincludes)),\0033[1m$(file)\0033[22m|$(call typeoffile,$(file))|[\0033[3m$(if $(filter $(file),$(xmlfiles)),xml,$(if $(filter $(file),$(plaintextfiles)),text,asset))$(if $(filter $(file),$(sourceincludes)),|include,)\0033[23m] Modified:|$(call modtime,$(file))$(if $(call dependencies,$(file))$(call recursives,$(file)), $(strip $(foreach recursive,$(call recursives,$(file)),\0033[93;41m•|Recursive|Dependency|\0033[39;49m|$(recursive)) $(foreach dependency,$(call dependencies,$(file)),\0033[2m•|Dependency|\0033[22m|$(dependency))))$(if $(filter $(file),$(sourcefiles)), →|<\0033[4m/$(call destination,$(file))\0033[24m>,) )) | $(TR) ' |' '\n '
 
 # Lists out the destinations of all resulting files (relative to `DESTDIR´).
 listout :

diff --git a/README.markdown b/README.markdown
index d459604c1709aaf9632bf19b1600e85521461d1f..952f4ee07fe25899ae0fa3aa4a3b358b85709462 100644 (file)
--- a/README.markdown
+++ b/README.markdown
@@ -57,13 +57,6 @@ Details on particular programs are given below; if a program is not
   listed, it is assumed that any Posix‐compliant implementation will
   work.
 
-### `date`
-
-This is a Posix utility, but ⛩️📰 书社 currently depends on
-  unspecified behaviour.
-When the G·N·U version of `stat` is being used, then the G·N·U version
-  of `date` is also expected.
-
 ### `file`
 
 This is a Posix utility, but ⛩️📰 书社 currently depends on
@@ -108,13 +101,6 @@ This is a Posix utility, but not included in the Linux Standard Base or
   installed by default in many distributions.
 Only `ustar` format support is required.
 
-### `stat`
-
-This is not a Posix utility, and nor is it particularly portable.
-To get around incompatibilities, ⛩️📰 书社 attempts to recognize G·N·U
-  `stat` by searching for the string `GNU` when invoked with the
-  `--version` option, and falls back to B·S·D behaviour otherwise.
-
 ### `uudecode` and `uuencode`
 
 These are Posix utilities, but not included in the Linux Standard Base
@@ -212,7 +198,6 @@ In every case, you may supply your own implementation by overriding the
 - `rm`
 - `sed`
 - `sleep`
-- `stat` (BSD *or* GNU)
 - `test`
 - `touch`
 - `tr`
@@ -579,6 +564,10 @@ The following params are made available globally in parsers and
 
 - **`SRCTIME`:**
   The time at which the source file was last modified.
+  Due to limitations in Posix, this time will only have minute
+    precision if the file was modified in the last six months, and will
+    only have day precision if the file is older.
+  Users should not expect this value to be particularly stable.
 
 - **`THISREV`:**
   The value of the `THISREV` variable (if present).