1. preprocessor doesn't touch unchanged files anymore

2. doublechedk on whether file is up to date when making
3. changed the way preprocessor targets depend on the timestamp file
4. a bugfix in strip_suffix/strip_prefix

5 files changed, 95 insertions, 22 deletions

diff --git a/include/sitecing/sitecing_enflesher.h b/include/sitecing/sitecing_enflesher.h
index 512a358..8bc43a0 100644
--- a/include/sitecing/sitecing_enflesher.h
+++ b/include/sitecing/sitecing_enflesher.h
@@ -44,2 +44,7 @@ class sitecing_enflesher : public sitecing_enflesherFlexLexer {
         ofstream outs;
+        /**
+         * the outs stream destination file.
+         * @see outs
+         */
+        string outs_filename;
 
@@ -63,2 +68,10 @@ class sitecing_enflesher : public sitecing_enflesherFlexLexer {
         void anchor();
+
+        /**
+         * Close previously opened output stream, rename to the 'correct'
+         * destination filename, if needed, and open new file.
+         * @see outs
+         * @see outs_filename
+         */
+        void outs_open(const string& nfile);
 };
diff --git a/lib/component_factory.cc b/lib/component_factory.cc
index f8666dc..b8f5a16 100644
--- a/lib/component_factory.cc
+++ b/lib/component_factory.cc
@@ -21,3 +21,3 @@ namespace sitecing {
 
-    static const char *pp_targets[] = { ".cc", ".h", ".imports", ".classname", ".baseclassname", ".ancestors" };
+    static const char *pp_targets[] = { ".cc", ".h", ".imports", ".classname", ".baseclassname", ".ancestors", ".pp_stamp" };
     static const char *cc_targets[] = { ".o", ".d" };
@@ -118,6 +118,12 @@ namespace sitecing {
         try {
-            strip_prefix(dp,root_intermediate);
-            return file_factory::is_uptodate(dst,deps);
-        }catch(utility_no_prefix& unp) {
-        }
+            string noro = strip_prefix(dp,root_intermediate);
+            for(int ppt=0;(ppt+1)<sizeof(pp_targets)/sizeof(*pp_targets);ppt++) {
+                try {
+                    string nos = strip_suffix(noro,pp_targets[ppt]);
+                    return file_factory::is_uptodate(root_intermediate+nos+".pp_stamp",deps);
+                }catch(utility_no_suffix& uns) { }
+            }
+            bool rv =  file_factory::is_uptodate(dst,deps);
+            return rv;
+        }catch(utility_no_prefix& unp) { }
         try {
@@ -125,4 +131,3 @@ namespace sitecing {
             return file_factory::is_uptodate(dst,deps);
-        }catch(utility_no_prefix& unp) {
-        }
+        }catch(utility_no_prefix& unp) { }
         return true;
@@ -251,2 +256,4 @@ namespace sitecing {
                     parser.preprocess(src);
+                    string sf = root_intermediate+noro+".pp_stamp";
+                    ofstream sfs(sf.c_str(),ios::trunc|ios::out); // touch .pp_stamp
                 }catch(preprocessor_error& pe) {
diff --git a/lib/file_factory.cc b/lib/file_factory.cc
index c6b5748..7ca7b86 100644
--- a/lib/file_factory.cc
+++ b/lib/file_factory.cc
@@ -41,3 +41,4 @@ namespace sitecing {
                     make(*i);
-                build(dst);
+                if(!is_uptodate(dst,&deps))
+                    build(dst);
             }
diff --git a/lib/sitecing_enflesher.ll b/lib/sitecing_enflesher.ll
index 5f631d7..46489c7 100644
--- a/lib/sitecing_enflesher.ll
+++ b/lib/sitecing_enflesher.ll
@@ -24,8 +24,3 @@ ID	[A-Za-z_][A-Za-z0-9_]*
     line.erase(line.length()-1);
-    outs.flush();
-    outs.close();
-    outs.clear();
-    outs.open((parser.output_basename+line).c_str(),ios::trunc);
-    if(!outs.good())
-        throw preprocessor_error(CODEPOINT,"failed to write preprocessor output");
+    outs_open(parser.output_basename+line);
     anchor();
@@ -37,8 +32,3 @@ ID	[A-Za-z_][A-Za-z0-9_]*
     line.erase(line.length()-1);
-    outs.flush();
-    outs.close();
-    outs.clear();
-    outs.open((parser.output_basename+line).c_str(),ios::trunc);
-    if(!outs.good())
-        throw preprocessor_error(CODEPOINT,"failed to write preprocessor output");
+    outs_open(parser.output_basename+line);
     anchoraged = false;
@@ -199,2 +189,64 @@ void sitecing_enflesher::anchor() {
 }
+
+void sitecing_enflesher::outs_open(const string& nfile) {
+    if(!outs_filename.empty()) {
+        outs.flush();
+        outs.close();
+        outs.clear();
+        /*
+         * compare source and destination files.
+         *
+         * one can also keep a hash for the old one and compute one for the
+         * output while writing, but I'm not sure if it's any better. Surely a
+         * bit less accurate, unless we're going to compare it in case of
+         * difference, anyway.
+         */
+        bool overwrite = false;
+        struct stat st_s, st_d;
+        string fn_s = outs_filename+".new";
+        string fn_d = outs_filename;
+        if(stat(fn_d.c_str(),&st_d)) {
+            overwrite = true;
+        }else{
+            if(stat(fn_s.c_str(),&st_s))
+                throw preprocessor_error(CODEPOINT,"failed to stat() supposedly created file");
+            if(st_s.st_size!=st_d.st_size) {
+                overwrite = true;
+            }else{
+                ifstream i_s(fn_s.c_str(),ios::in);
+                if(!i_s)
+                    throw preprocessor_error(CODEPOINT,"failed to open supposedly created file");
+                ifstream i_d(fn_d.c_str(),ios::in);
+                if(!i_d)
+                    throw preprocessor_error(CODEPOINT,"failed to open the old preprocessed source");
+                off_t remaining = st_s.st_size;
+                char t1[2048];
+                char t2[sizeof(t1)];
+                while(remaining) {
+                    int rb = remaining;
+                    if(rb>sizeof(t1))
+                        rb = sizeof(t1);
+                    if(i_s.read(t1,rb).gcount()!=rb)
+                        throw preprocessor_error(CODEPOINT,"error reading just created file");
+                    if(i_d.read(t2,rb).gcount()!=rb)
+                        throw preprocessor_error(CODEPOINT,"error reading the old preprocessed source");
+                    if(memcmp(t1,t2,rb)) {
+                        overwrite = true;
+                        break;
+                    }
+                    remaining -= rb;
+                }
+            }
+        }
+        if(overwrite) {
+            cerr << "renaming '" << fn_s << "'" << endl;
+            if(rename(fn_s.c_str(),fn_d.c_str()))
+                throw preprocessor_error(CODEPOINT,"failed to rename() generated output");
+        }
+    }
+    outs_filename = nfile;
+    outs.open((nfile+".new").c_str(),ios::trunc);
+    if(!outs.good())
+        throw preprocessor_error(CODEPOINT,"failed to write preprocessor output");
+}
 /*
diff --git a/lib/sitecing_util.cc b/lib/sitecing_util.cc
index 5466b28..f892a60 100644
--- a/lib/sitecing_util.cc
+++ b/lib/sitecing_util.cc
@@ -58,3 +58,3 @@ namespace sitecing {
     string strip_prefix(const string& str,const string& prefix) {
-        if(str.compare(0,prefix.length(),prefix))
+        if( (str.length()<prefix.length()) || str.compare(0,prefix.length(),prefix))
             throw utility_no_prefix(CODEPOINT,"no such prefix");
@@ -64,3 +64,3 @@ namespace sitecing {
     string strip_suffix(const string& str,const string& suffix) {
-        if(str.compare(str.length()-suffix.length(),suffix.length(),suffix))
+        if( (str.length()<suffix.length()) || str.compare(str.length()-suffix.length(),suffix.length(),suffix))
             throw utility_no_suffix(CODEPOINT,"no such suffix");