Implement tracing support

Also use to-relative path translation in diagnostics.

16 files changed, 343 insertions, 28 deletions

diff --git a/build/algorithm.cxx b/build/algorithm.cxx
index fac0bf6..419bfaf 100644
--- a/build/algorithm.cxx
+++ b/build/algorithm.cxx
@@ -23,6 +23,8 @@ namespace build
   target*
   search (prerequisite& p)
   {
+    tracer tr ("search");
+
     assert (p.target == nullptr);
 
     //@@ TODO for now we just default to the directory scope.
@@ -36,7 +38,7 @@ namespace build
       d.normalize ();
     }
 
-    //@@ TODO would be nice to first check if this target is
+    //@@ TODO: would be nice to first check if this target is
     //   already in the set before allocating a new instance.
 
     // Find or insert.
@@ -45,8 +47,9 @@ namespace build
       targets.emplace (
         unique_ptr<target> (p.type.factory (p.name, move (d)))));
 
-    //if (r.second)
-    //  cout << "new target for prerequsite " << p << " " << d << endl;
+    trace (4, [&]{
+        tr << (r.second ? "new" : "existing") << " target " << **r.first
+           << " for prerequsite " << p;});
 
     return (p.target = r.first->get ());
   }
diff --git a/build/b.cxx b/build/b.cxx
index a5123f1..ad68e21 100644
--- a/build/b.cxx
+++ b/build/b.cxx
@@ -110,6 +110,8 @@ namespace build
   void
   dump ()
   {
+    cout << endl;
+
     for (const auto& pt: targets)
     {
       target& t (*pt);
@@ -123,6 +125,8 @@ namespace build
 
       cout << endl;
     }
+
+    cout << endl;
   }
 
 }
@@ -138,10 +142,16 @@ using namespace build;
 int
 main (int argc, char* argv[])
 {
+  tracer tr ("main");
+
   // Initialize time conversion data that is used by localtime_r().
   //
   tzset ();
 
+  // Trace verbosity.
+  //
+  verb = 5;
+
   // Register target types.
   //
   target_types.insert (file::static_type);
@@ -200,12 +210,15 @@ main (int argc, char* argv[])
   else
     out_root = out_base.directory (src_base.leaf (src_root));
 
-  cerr << "work dir: " << work << endl;
-  cerr << "home dir: " << home << endl;
-  cerr << "out_base: " << out_base << endl;
-  cerr << "src_base: " << src_base << endl;
-  cerr << "out_root: " << out_root << endl;
-  cerr << "src_root: " << src_root << endl;
+  if (verb >= 4)
+  {
+    tr << "work dir: " << work.string ();
+    tr << "home dir: " << home.string ();
+    tr << "out_base: " << out_base.string ();
+    tr << "src_base: " << src_base.string ();
+    tr << "out_root: " << out_root.string ();
+    tr << "src_root: " << src_root.string ();
+  }
 
   // Parse buildfile.
   //
@@ -267,7 +280,7 @@ main (int argc, char* argv[])
     if (!match_recursive (d))
       return 1; // Diagnostics has already been issued.
 
-    //dump ();
+    dump ();
 
     switch (update (d))
     {
diff --git a/build/buildfile b/build/buildfile
index 88ea4d6..3afe19b 100644
--- a/build/buildfile
+++ b/build/buildfile
@@ -1,16 +1,18 @@
-exe{b1}: obj{b algorithm scope parser lexer target prerequisite rule \
-  native context cxx/target cxx/rule process timestamp path}
+exe{b1}: obj{b algorithm scope parser lexer trace target prerequisite rule \
+  native context diagnostics cxx/target cxx/rule process timestamp path}
 
 obj{b}: cxx{b}
 obj{algorithm}: cxx{algorithm}
 obj{scope}: cxx{scope}
 obj{parser}: cxx{parser}
 obj{lexer}: cxx{lexer}
+obj{trace}: cxx{trace}
 obj{target}: cxx{target}
 obj{prerequisite}: cxx{prerequisite}
 obj{rule}: cxx{rule}
 obj{native}: cxx{native}
 obj{context}: cxx{context}
+obj{diagnostics}: cxx{diagnostics}
 obj{cxx/target}: cxx{cxx/target}
 obj{cxx/rule}: cxx{cxx/rule}
 obj{process}: cxx{process}
diff --git a/build/context b/build/context
index 4c86b14..a369ade 100644
--- a/build/context
+++ b/build/context
@@ -5,6 +5,9 @@
 #ifndef BUILD_CONTEXT
 #define BUILD_CONTEXT
 
+#include <string>
+#include <ostream>
+
 #include <build/path>
 
 namespace build
@@ -17,6 +20,24 @@ namespace build
 
   extern path src_base;
   extern path out_base;
+
+  // If possible, translate an absolute, normalized path into relative to
+  // the work directory.
+  //
+  path
+  translate (const path&);
+
+  // In addition to calling translate() above, this function also uses
+  // shorter notations such as ~/.
+  //
+  std::string
+  diagnostic_string (const path&);
+
+  inline std::ostream&
+  operator<< (std::ostream& os, const path& p)
+  {
+    return os << diagnostic_string (p);
+  }
 }
 
 #endif // BUILD_CONTEXT
diff --git a/build/context.cxx b/build/context.cxx
index ce80324..fc4ec1c 100644
--- a/build/context.cxx
+++ b/build/context.cxx
@@ -2,6 +2,8 @@
 // copyright : Copyright (c) 2014-2015 Code Synthesis Tools CC
 // license   : MIT; see accompanying LICENSE file
 
+#include <ostream>
+
 #include <build/context>
 
 using namespace std;
@@ -16,4 +18,38 @@ namespace build
 
   path src_base;
   path out_base;
+
+  path
+  translate (const path& p)
+  {
+    if (p.sub (work))
+      return p.leaf (work);
+
+    // If work is a sub-path of {src,out}_root and this path is also a
+    // sub-bath of it, then use '..' to form a relative path.
+    //
+    if (work.sub (src_root) && p.sub (src_root) ||
+        work.sub (out_root) && p.sub (out_root)) // @@ cache
+      return p.relative (work);
+
+    return p;
+  }
+
+  std::string
+  diagnostic_string (const path& p)
+  {
+    if (p.absolute ())
+    {
+      path rp (translate (p));
+
+#ifndef _WIN32
+      if (rp.absolute () && rp.sub (home))
+        return "~/" + rp.leaf (home).string ();
+#endif
+
+      return rp.string ();
+    }
+
+    return p.string ();
+  }
 }
diff --git a/build/cxx/rule.cxx b/build/cxx/rule.cxx
index 3cab2d4..1d2a2c4 100644
--- a/build/cxx/rule.cxx
+++ b/build/cxx/rule.cxx
@@ -17,6 +17,7 @@
 #include <build/process>
 #include <build/timestamp>
 #include <build/diagnostics>
+#include <build/context>
 
 using namespace std;
 
@@ -29,6 +30,8 @@ namespace build
     recipe compile::
     match (target& t) const
     {
+      tracer tr ("cxx::compile::match");
+
       // @@ TODO:
       //
       // - check prerequisites: single source file
@@ -59,7 +62,7 @@ namespace build
 
       if (sp == nullptr)
       {
-        cout << "no source file" << endl;
+        trace (3, [&]{tr << "no c++ source file for target " << t;});
         return recipe ();
       }
 
@@ -137,16 +140,27 @@ namespace build
     void compile::
     inject_prerequisites (obj& o, const cxx& s, scope& ds) const
     {
+      tracer tr ("cxx::compile::inject_prerequisites");
+
+      // We are using absolute source file path in order to get
+      // absolute paths in the result.
+      //
       const char* args[] = {
         "g++-4.9",
         "-std=c++14",
-        "-I..",
-        "-MM",      //@@ TMP -M
+        "-I", src_root.string ().c_str (),
+        "-MM",       //@@ -M
         "-MG",      // Treat missing headers as generated.
         "-MQ", "*", // Quoted target (older version can't handle empty name).
         s.path ().string ().c_str (),
         nullptr};
 
+      if (verb >= 2)
+        print_process (args);
+
+      if (verb >= 5)
+        tr << "target: " << o;
+
       try
       {
         process pr (args, false, false, true);
@@ -186,6 +200,9 @@ namespace build
             path file (next (l, pos));
             file.normalize ();
 
+            if (verb >= 5)
+              tr << "prerequisite path: " << file.string ();
+
             // If there is no extension (e.g., standard C++ headers),
             // then assume it is a header. Otherwise, let the standard
             // mechanism derive the type from the extension.
@@ -282,17 +299,26 @@ namespace build
       if (!u)
         return target_state::uptodate;
 
+      // Translate paths to relative (to working directory) ones. This
+      // results in easier to read diagnostics.
+      //
+      path ro (translate (o.path ()));
+      path rs (translate (s->path ()));
+
       const char* args[] = {
         "g++-4.9",
         "-std=c++14",
         "-g",
-        "-I..",
+        "-I", src_root.string ().c_str (),
         "-c",
-        "-o", o.path ().string ().c_str (),
-        s->path ().string ().c_str (),
+        "-o", ro.string ().c_str (),
+        rs.string ().c_str (),
         nullptr};
 
-      cerr << "c++ " << *s << endl;
+      if (verb >= 1)
+        print_process (args);
+      else
+        cerr << "c++ " << *s << endl;
 
       try
       {
@@ -407,19 +433,29 @@ namespace build
       if (!u)
         return target_state::uptodate;
 
+      // Translate paths to relative (to working directory) ones. This
+      // results in easier to read diagnostics.
+      //
+      path re (translate (e.path ()));
+      vector<path> ro;
+
       vector<const char*> args {"g++-4.9", "-std=c++14", "-g", "-o"};
 
-      args.push_back (e.path ().string ().c_str ());
+      args.push_back (re.string ().c_str ());
 
       for (const prerequisite& p: t.prerequisites)
       {
         const obj& o (dynamic_cast<const obj&> (*p.target));
-        args.push_back (o.path ().string ().c_str ());
+        ro.push_back (translate (o.path ()));
+        args.push_back (ro.back ().string ().c_str ());
       }
 
       args.push_back (nullptr);
 
-      cerr << "ld " << e << endl;
+      if (verb >= 1)
+        print_process (args);
+      else
+        cerr << "ld " << e << endl;
 
       try
       {
diff --git a/build/diagnostics b/build/diagnostics
index c8fb169..98f481f 100644
--- a/build/diagnostics
+++ b/build/diagnostics
@@ -6,9 +6,12 @@
 #define BUILD_DIAGNOSTICS
 
 #include <tuple>
+#include <vector>
 #include <utility>
 #include <exception>
 
+#include <build/trace>
+
 namespace build
 {
   // Throw this exception to terminate the build. The handler should
@@ -16,6 +19,17 @@ namespace build
   //
   class error: public std::exception {};
 
+  // Print process commmand line.
+  //
+  void
+  print_process (const char* const* args);
+
+  inline void
+  print_process (const std::vector<const char*>& args)
+  {
+    print_process (args.data ());
+  }
+
   // Call a function if there is an exception.
   //
   template <typename F, typename T>
diff --git a/build/diagnostics.cxx b/build/diagnostics.cxx
new file mode 100644
index 0000000..f213707
--- /dev/null
+++ b/build/diagnostics.cxx
@@ -0,0 +1,20 @@
+// file      : build/diagnostics.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2015 Code Synthesis Tools CC
+// license   : MIT; see accompanying LICENSE file
+
+#include <build/diagnostics>
+
+#include <iostream>
+
+using namespace std;
+
+namespace build
+{
+  void
+  print_process (const char* const* args)
+  {
+    for (const char* const* p (args); *p != nullptr; p++)
+      cerr << (p != args ? " " : "") << *p;
+    cerr << endl;
+  }
+}
diff --git a/build/parser.cxx b/build/parser.cxx
index e300201..289e571 100644
--- a/build/parser.cxx
+++ b/build/parser.cxx
@@ -243,6 +243,7 @@ namespace build
               if (p.relative ())
                 p = prev.path () / p;
 
+              p.normalize ();
               scope_ = &scopes[p];
 
               // A directory scope can contain anything that a top level can.
diff --git a/build/path b/build/path
index ccc1b85..92832a1 100644
--- a/build/path
+++ b/build/path
@@ -218,6 +218,16 @@ namespace build
     bool
     root () const;
 
+    // Return true if *this is a sub-path of the specified path (i.e.,
+    // the specified path is a prefix). Expects both paths to be
+    // normalized.
+    //
+    bool
+    sub (const basic_path& p) const
+    {
+      return path_.compare (0, p.path_.size (), p.path_) == 0;
+    }
+
   public:
     // Return the path without the directory part.
     //
@@ -249,6 +259,13 @@ namespace build
     basic_path
     base () const;
 
+    // Return a path relative to the specified path that is equivalent
+    // to *this. Throws invalid_path if a relative path cannot be derived
+    // (e.g., paths are on different drives on Windows).
+    //
+    basic_path
+    relative (basic_path) const;
+
   public:
     // Normalize the path. This includes collapsing the '.' and '..'
     // directories if possible, collapsing multiple directory
@@ -334,12 +351,14 @@ namespace build
     string_type path_;
   };
 
+  /*
   template <typename C>
   inline std::basic_ostream<C>&
   operator<< (std::basic_ostream<C>& os, basic_path<C> const& p)
   {
     return os << p.string ();
   }
+  */
 }
 
 #include <build/path.ixx>
diff --git a/build/path.txx b/build/path.txx
index 6a01547..3e952d8 100644
--- a/build/path.txx
+++ b/build/path.txx
@@ -117,8 +117,12 @@ namespace build
     if (m < n || path_.compare (0, n, d.path_) != 0)
       throw invalid_basic_path<C> (path_);
 
-    if (n != m)
-      n++; // Skip the directory separator.
+    if (n != m
+#ifndef _WIN32
+        && !d.root ()
+#endif
+    )
+      n++; // Skip the directory separator (unless it is POSIX root).
 
     return basic_path (path_.c_str () + n, m - n);
   }
@@ -144,6 +148,28 @@ namespace build
   }
 
   template <typename C>
+  basic_path<C> basic_path<C>::
+  relative (basic_path<C> d) const
+  {
+    basic_path r;
+
+    for (;; d = d.directory ())
+    {
+      if (sub (d))
+        break;
+
+      r /= path ("..");
+
+      // Roots of the paths do not match.
+      //
+      if (d.root ())
+        throw invalid_basic_path<C> (path_);
+    }
+
+    return r / leaf (d);
+  }
+
+  template <typename C>
   basic_path<C>& basic_path<C>::
   normalize ()
   {
diff --git a/build/pre.build b/build/pre.build
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/build/pre.build
diff --git a/build/prerequisite.cxx b/build/prerequisite.cxx
index 8153a6c..c43827d 100644
--- a/build/prerequisite.cxx
+++ b/build/prerequisite.cxx
@@ -6,7 +6,9 @@
 
 #include <ostream>
 
+#include <build/scope>
 #include <build/target> // target_type
+#include <build/context>
 
 using namespace std;
 
@@ -15,9 +17,36 @@ namespace build
   ostream&
   operator<< (ostream& os, const prerequisite& p)
   {
-    // @@ TODO: need to come up with a relative (to current) path.
+    if (p.target != nullptr)
+      os << *p.target;
+    else
+    {
+      os << p.type.name << '{';
 
-    return os << p.type.name << '{' << p.name << '}';
+      // Print scope unless the directory is absolute.
+      //
+      if (!p.directory.absolute ())
+      {
+        string s (diagnostic_string (p.scope.path ()));
+
+        if (!s.empty ())
+          os << s << path::traits::directory_separator << ": ";
+      }
+
+      // Print directory.
+      //
+      if (!p.directory.empty ())
+      {
+        string s (diagnostic_string (p.directory));
+
+        if (!s.empty ())
+          os << s << path::traits::directory_separator;
+      }
+
+      os << p.name << '}';
+    }
+
+    return os;
   }
 
   bool
diff --git a/build/target.cxx b/build/target.cxx
index 8314ba4..4dffe7f 100644
--- a/build/target.cxx
+++ b/build/target.cxx
@@ -6,6 +6,8 @@
 
 #include <ostream>
 
+#include <build/context>
+
 using namespace std;
 
 namespace build
@@ -15,9 +17,19 @@ namespace build
   ostream&
   operator<< (ostream& os, const target& t)
   {
-    // @@ TODO: need to come up with a relative (to current) path.
+    os << t.type ().name << '{';
+
+    if (!t.directory.empty ())
+    {
+      string s (diagnostic_string (t.directory));
+
+      if (!s.empty ())
+        os << s << path::traits::directory_separator;
+    }
+
+    os << t.name << '}';
 
-    return os << t.type ().name << '{' << t.name << '}';
+    return os;
   }
 
   target_set targets;
diff --git a/build/trace b/build/trace
new file mode 100644
index 0000000..f1c0567
--- /dev/null
+++ b/build/trace
@@ -0,0 +1,71 @@
+// file      : build/trace -*- C++ -*-
+// copyright : Copyright (c) 2014-2015 Code Synthesis Tools CC
+// license   : MIT; see accompanying LICENSE file
+
+#ifndef BUILD_TRACE
+#define BUILD_TRACE
+
+#include <cstdint>
+#include <iostream>
+
+namespace build
+{
+  // 1 - command lines to update explicit targets (e.g., .o)
+  // 2 - command lines to update implicit targets (e.g., .d)
+  // 3 - things didn't work out (e.g., rule did not match)
+  // 4 - additional information
+  // 5 - more additional information
+  //
+  extern std::uint8_t verb;
+
+  struct tracer
+  {
+    explicit
+    tracer (const char* name): name_ (name) {}
+
+    struct record
+    {
+      ~record () {if (!empty_) std::cerr << std::endl;}
+
+      template <typename T>
+      std::ostream&
+      operator<< (const T& x) const
+      {
+        return std::cerr << x;
+      }
+
+      // Movable-only type.
+      //
+      explicit record (bool e = true): empty_ (e) {}
+      record (record&& r) {empty_ = r.empty_; r.empty_ = true;}
+      record& operator= (record&& r) {empty_ = r.empty_; r.empty_ = true;}
+
+      record (const record&) = delete;
+      record& operator= (const record&) = delete;
+
+    private:
+      mutable bool empty_;
+    };
+
+    template <typename T>
+    record
+    operator<< (const T& x) const
+    {
+      std::cerr << "trace: " << name_ << ": " << x;
+      return record (false);
+    }
+
+  private:
+    const char* name_;
+  };
+
+  template <typename F>
+  inline void
+  trace (std::uint8_t level, const F& f)
+  {
+    if (verb >= level)
+      f ();
+  }
+}
+
+#endif // BUILD_TRACE
diff --git a/build/trace.cxx b/build/trace.cxx
new file mode 100644
index 0000000..a7e6566
--- /dev/null
+++ b/build/trace.cxx
@@ -0,0 +1,12 @@
+// file      : build/trace.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2015 Code Synthesis Tools CC
+// license   : MIT; see accompanying LICENSE file
+
+#include <build/trace>
+
+using namespace std;
+
+namespace build
+{
+  uint8_t verb;
+}