1 files changed, 87 insertions, 10 deletions

diff --git a/libbuild2/in/rule.hxx b/libbuild2/in/rule.hxx
index 2fa1305..67c2509 100644
--- a/libbuild2/in/rule.hxx
+++ b/libbuild2/in/rule.hxx
@@ -5,6 +5,7 @@
 #define LIBBUILD2_IN_RULE_HXX
 
 #include <libbuild2/types.hxx>
+#include <libbuild2/forward.hxx> // depdb
 #include <libbuild2/utility.hxx>
 
 #include <libbuild2/rule.hxx>
@@ -17,8 +18,14 @@ namespace build2
   {
     // Preprocess an .in file.
     //
-    // Note that a derived rule can use the target data pad to cache data
-    // (e.g., in match()) to be used in substitute/lookup() calls.
+    // Note that a derived rule can use the target auxiliary data storage to
+    // cache data (e.g., in match() or apply()) to be used in substitute() and
+    // lookup() calls.
+    //
+    // A derived rule is also required to derive the target file name in
+    // match() instead of apply() to make it available early for the in{}
+    // prerequisite search (see install::file_rule::apply_impl() for
+    // background).
     //
     // Note also that currently this rule ignores the dry-run mode (see
     // perform_update() for the rationale).
@@ -42,7 +49,7 @@ namespace build2
             null_ (move (null)) {}
 
       virtual bool
-      match (action, target&, const string&) const override;
+      match (action, target&) const override;
 
       virtual recipe
       apply (action, target&) const override;
@@ -50,24 +57,45 @@ namespace build2
       virtual target_state
       perform_update (action, const target&) const;
 
-      // Customization hooks.
+      // Customization hooks and helpers.
       //
+      using substitution_map = map<string, optional<string>>;
 
       // Perform prerequisite search.
       //
       virtual prerequisite_target
-      search (action,
-              const target&,
+      search (action, const target&,
               const prerequisite_member&,
               include_type) const;
 
+      // Additional depdb entries.
+      //
+      virtual void
+      perform_update_depdb (action, const target&, depdb&) const;
+
+      // Pre/post update.
+      //
+      virtual void
+      perform_update_pre (action, const target&,
+                          ofdstream&, const char* newline) const;
+
+      virtual void
+      perform_update_post (action, const target&,
+                           ofdstream&, const char* newline) const;
+
       // Perform variable lookup.
       //
+      // Flags can be used by a custom implementation to alter the lookup
+      // semantics, for example, for special substitutions. Note, however,
+      // that one must make sure this semantics cannot change without changes
+      // to the .in file (see the depdb logic for details).
+      //
       virtual string
       lookup (const location&,
-              action,
-              const target&,
+              action, const target&,
               const string& name,
+              optional<uint64_t> flags,
+              const substitution_map*,
               const optional<string>& null) const;
 
       // Perform variable substitution. Return nullopt if it should be
@@ -75,12 +103,61 @@ namespace build2
       //
       virtual optional<string>
       substitute (const location&,
-                  action,
-                  const target&,
+                  action, const target&,
                   const string& name,
+                  optional<uint64_t> flags,
                   bool strict,
+                  const substitution_map*,
                   const optional<string>& null) const;
 
+      // Call the above version and do any necessary depdb saving.
+      //
+      optional<string>
+      substitute (const location&,
+                  action, const target&,
+                  depdb& dd, size_t& dd_skip,
+                  const string& name,
+                  optional<uint64_t> flags,
+                  bool strict,
+                  const substitution_map*,
+                  const optional<string>& null) const;
+
+      // Process a line of input from the specified position performing any
+      // necessary substitutions.
+      //
+      virtual void
+      process (const location&,
+               action, const target&,
+               depdb& dd, size_t& dd_skip,
+               string& line, size_t pos,
+               const char* newline,
+               char sym,
+               bool strict,
+               const substitution_map*,
+               const optional<string>& null) const;
+
+      // Replace newlines in a multi-line value with the given newline
+      // sequence.
+      //
+      static void
+      replace_newlines (string& v, const char* newline)
+      {
+        for (size_t p (0), n; (p = v.find ('\n', p)) != string::npos; p += n)
+        {
+          n = 1;
+
+          // Deal with CRLF in the value.
+          //
+          if (p != 0 && v[p - 1] == '\r')
+          {
+            --p;
+            ++n;
+          }
+
+          v.replace (p, n, newline);
+        }
+      }
+
     protected:
       const string rule_id_;
       const string program_;