From 8b4cba6afa4b0d80acf3e3b3d81a3a562a461486 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Mon, 12 Feb 2024 15:51:53 +0200
Subject: [PATCH] Add support for #cmakedefine01 (GH issue #63)

---
 README.md                                     |  4 +-
 libbuild2-autoconf-tests/module/testscript    | 21 +++++++
 .../libbuild2/autoconf/rule.cxx               | 62 +++++++++++++++++--
 3 files changed, 80 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index 3be743d..a214738 100644
--- a/README.md
+++ b/README.md
@@ -4,8 +4,8 @@ GNU Autoconf emulation build system module for `build2`.
 
 Specifically, this module provides an [`in`][module-in]-based rule for
 processing `config.h.in` files. Besides the Autoconf special line flavor
-(`#undef`), it also supports the CMake (`#cmakedefine`) and Meson
-(`#mesondefine`) variants.
+(`#undef`), it also supports the CMake (`#cmakedefine`, `#cmakedefine01`) and
+Meson (`#mesondefine`) variants.
 
 Similar to Autoconf, this module provides built-in support for a number of
 common `HAVE_*` configuration options. However, the values of these options
diff --git a/libbuild2-autoconf-tests/module/testscript b/libbuild2-autoconf-tests/module/testscript
index f7f0ea3..0f2611d 100644
--- a/libbuild2-autoconf-tests/module/testscript
+++ b/libbuild2-autoconf-tests/module/testscript
@@ -102,6 +102,14 @@ ln -s ../../bootstrap.build ../../root.build build/;
 cat <<EOI >=config.h.cmake;
   #define VERSION "@version@"
 
+  #cmakedefine01 TRUE01
+  #cmakedefine01 FALSE01
+  #cmakedefine01 ONE01
+  #cmakedefine01 ZERO01
+
+  #cmakedefine TRUE01
+  #cmakedefine FALSE01
+
   #cmakedefine TRUE
   #cmakedefine FALSE
   #cmakedefine ONE
@@ -131,6 +139,11 @@ cat <<EOI >=config.h.cmake;
 $* <<EOI &config.h &config.h.d;
   ./: h{config}: in{config.h.cmake}
   {
+    TRUE01  = true
+    FALSE01 = [bool] false
+    ONE01   = 1
+    ZERO01  = [uint64] 000
+
     TRUE  = true
     FALSE = [bool] false
     ONE   = 1
@@ -165,6 +178,14 @@ $* <<EOI &config.h &config.h.d;
 cat config.h >>EOO
   #define VERSION "1.2.3"
 
+  #define TRUE01 1
+  #define FALSE01 0
+  #define ONE01 1
+  #define ZERO01 0
+
+  /* TRUE01 already defined. */
+  /* FALSE01 already defined. */
+
   #define TRUE 1
   #undef FALSE
   #define ONE 1
diff --git a/libbuild2-autoconf/libbuild2/autoconf/rule.cxx b/libbuild2-autoconf/libbuild2/autoconf/rule.cxx
index 620a8ba..7904869 100644
--- a/libbuild2-autoconf/libbuild2/autoconf/rule.cxx
+++ b/libbuild2-autoconf/libbuild2/autoconf/rule.cxx
@@ -177,7 +177,7 @@ namespace build2
 
       flavor f (t.data<match_data> (a).flavor);
 
-      // Substitute special #undef/#cmakedfine/#mesondefine line. If value is
+      // Substitute special #undef/#cmakedefine/#mesondefine line. If value is
       // false, then do not append the value to #define.
       //
       // Return true if it was substituted with #define, false if with #undef,
@@ -291,6 +291,41 @@ namespace build2
         return r;
       };
 
+      // Substitute special #cmakedefine01 line with #define 0 or 1.
+      //
+      auto substitute_special01 = [this,
+                                   &l,
+                                   a, &t,
+                                   &dd, &dd_skip,
+                                   strict, smap, &null,
+                                   &s] (const string& name)
+      {
+        // Essentially a simplified version of substitute_special() above.
+        //
+        optional<string> ov (substitute (l,
+                                         a, t,
+                                         dd, dd_skip,
+                                         name, 1 /* flags */,
+                                         strict, smap, null));
+
+        assert (ov);
+        string& v (*ov);
+
+        if (v == "0" || v == "1")
+          ;
+        else if (v == "false")
+          v = "0";
+        else if (v == "true")
+          v = "1";
+        else
+          fail (l) << "variable " << name << " should be false/0 or true/1";
+
+        s = "#define ";
+        s += name;
+        s += ' ';
+        s += v;
+      };
+
       // Deal with special lines of each flavor. Return if the line has has
       // been handled and fall through to use the normal substitution logic.
       //
@@ -378,9 +413,7 @@ namespace build2
           // #cmakedefine size_t @SIZE_T@
           //
           // The #cmakedefine01 variant is always replaced with #define,
-          // either with value 1 if NAME is true and 0 otherwise. It's doesn't
-          // appear to be used much in practice so we are not going to bother
-          // with it.
+          // either with value 1 if NAME is true and 0 otherwise.
           //
           skip_ws (s, i);
 
@@ -423,7 +456,26 @@ namespace build2
               s += *value;
             }
             else if (s.compare (i, 13, "cmakedefine01") == 0 && ws (s[i + 13]))
-              fail(l) << "#cmakedefine01 is not yet supported";
+            {
+              i += 13;
+              skip_ws (s, i);
+
+              size_t n (read_id (s, i));
+
+              if (n == 0)
+                fail (l) << "expected identifier after #cmakedefine01";
+
+              string name (s, i, n);
+
+              i += n;
+              skip_ws (s, i);
+
+              if (s[i] != '\0')
+                fail (l) << "junk after variable name in #cmakedefine01";
+
+              substitute_special01 (name);
+              return;
+            }
           }
           break;
         }