Change depdb API and handle system_error thrown by butl::file_mtime()

Previously, debdb operations threw system_error and io_error to signal errors,
except for opening which issued diagnostics and failed. Now all operations
print the diagnostics and fail on system and IO errors.

15 files changed, 60 insertions, 34 deletions

diff --git a/build2/cc/common.cxx b/build2/cc/common.cxx
index 7844a4e..aca1240 100644
--- a/build2/cc/common.cxx
+++ b/build2/cc/common.cxx
@@ -639,7 +639,7 @@ namespace build2
         {
           f = d;
           f /= sn;
-          mt = file_mtime (f);
+          mt = mtime (f);
 
           if (mt != timestamp_nonexistent)
           {
@@ -694,7 +694,7 @@ namespace build2
             //
             se = string ("dll");
             f = f.base (); // Remove .a from .dll.a.
-            mt = file_mtime (f);
+            mt = mtime (f);
 
             if (mt != timestamp_nonexistent)
             {
@@ -715,7 +715,7 @@ namespace build2
           f = d;
           f /= an;
 
-          if ((mt = file_mtime (f)) != timestamp_nonexistent)
+          if ((mt = mtime (f)) != timestamp_nonexistent)
           {
             // Enter the target. Note that because the search paths are
             // normalized, the result is automatically normalized as well.
diff --git a/build2/cc/compile-rule.cxx b/build2/cc/compile-rule.cxx
index eeaec83..aa1d6fb 100644
--- a/build2/cc/compile-rule.cxx
+++ b/build2/cc/compile-rule.cxx
@@ -13,6 +13,7 @@
 #include <build2/context.hxx>
 #include <build2/variable.hxx>
 #include <build2/algorithm.hxx>
+#include <build2/filesystem.hxx>  // mtime()
 #include <build2/diagnostics.hxx>
 
 #include <build2/bin/target.hxx>
@@ -823,7 +824,7 @@ namespace build2
         // the target (interrupted update), then do unconditional update.
         //
         timestamp mt;
-        bool u (dd.writing () || dd.mtime > (mt = file_mtime (tp)));
+        bool u (dd.writing () || dd.mtime > (mt = mtime (tp)));
         if (u)
           mt = timestamp_nonexistent; // Treat as if it doesn't exist.
 
diff --git a/build2/cc/link-rule.cxx b/build2/cc/link-rule.cxx
index 6c6aa0d..cffd731 100644
--- a/build2/cc/link-rule.cxx
+++ b/build2/cc/link-rule.cxx
@@ -1689,7 +1689,7 @@ namespace build2
         path& mf (p.first);
         bool mf_cf (p.second); // Changed flag (timestamp resolution).
 
-        timestamp mf_mt (file_mtime (mf));
+        timestamp mf_mt (mtime (mf));
 
         if (tsys == "mingw32")
         {
@@ -1699,7 +1699,7 @@ namespace build2
           //
           manifest = mf + ".o";
 
-          if (mf_mt > file_mtime (manifest) || mf_cf)
+          if (mf_mt > mtime (manifest) || mf_cf)
           {
             path of (relative (manifest));
 
diff --git a/build2/cc/msvc.cxx b/build2/cc/msvc.cxx
index 78c29e0..32805c7 100644
--- a/build2/cc/msvc.cxx
+++ b/build2/cc/msvc.cxx
@@ -396,7 +396,7 @@ namespace build2
 
       // Check if the file exists and is of the expected type.
       //
-      timestamp mt (file_mtime (f));
+      timestamp mt (mtime (f));
 
       if (mt != timestamp_nonexistent && library_type (ld, f) == lt)
       {
diff --git a/build2/cc/pkgconfig.cxx b/build2/cc/pkgconfig.cxx
index 3e477d8..eef1271 100644
--- a/build2/cc/pkgconfig.cxx
+++ b/build2/cc/pkgconfig.cxx
@@ -1178,7 +1178,7 @@ namespace build2
       // that, if we add it as a prerequisite (like we do above), the fallback
       // file rule won't match.
       //
-      lt.mtime (file_mtime (ipc.path));
+      lt.mtime (mtime (ipc.path));
     }
 
 #else
diff --git a/build2/cc/windows-rpath.cxx b/build2/cc/windows-rpath.cxx
index 8161cc4..46fe75b 100644
--- a/build2/cc/windows-rpath.cxx
+++ b/build2/cc/windows-rpath.cxx
@@ -102,7 +102,7 @@ namespace build2
         //
         timestamp t (l != nullptr
                      ? l->load_mtime ()
-                     : file_mtime (f.c_str ()));
+                     : mtime (f.c_str ()));
 
         if (t > r)
           r = t;
@@ -260,7 +260,7 @@ namespace build2
         // through the "from scratch" update. Actually this can happen when
         // switching to update-for-install.
         //
-        if (ts != timestamp_nonexistent && ts <= file_mtime (am))
+        if (ts != timestamp_nonexistent && ts <= mtime (am))
           return;
       }
 
diff --git a/build2/depdb.cxx b/build2/depdb.cxx
index da56c8b..605ceb4 100644
--- a/build2/depdb.cxx
+++ b/build2/depdb.cxx
@@ -4,12 +4,11 @@
 
 #include <build2/depdb.hxx>
 
-#include <libbutl/filesystem.mxx> // file_mtime()
-
 #ifdef _WIN32
 #  include <libbutl/win32-utility.hxx>
 #endif
 
+#include <build2/filesystem.hxx>  // mtime()
 #include <build2/diagnostics.hxx>
 
 using namespace std;
@@ -91,7 +90,7 @@ namespace build2
 
   depdb::
   depdb (path_type p)
-      : depdb (move (p), file_mtime (p))
+      : depdb (move (p), build2::mtime (p))
   {
   }
 
@@ -347,7 +346,7 @@ namespace build2
     // mtime. This seems to force that layer to commit to a timestamp.
     //
 #if defined(__FreeBSD__)
-    mtime = file_mtime (path); // Save for debugging/check below.
+    mtime = build2::mtime (path); // Save for debugging/check below.
 #endif
   }
 
@@ -357,8 +356,8 @@ namespace build2
     // We could call the static version but then we would have lost additional
     // information for some platforms.
     //
-    timestamp t_mt (file_mtime (t));
-    timestamp d_mt (file_mtime (path));
+    timestamp t_mt (build2::mtime (t));
+    timestamp d_mt (build2::mtime (path));
 
     if (d_mt > t_mt)
     {
@@ -382,8 +381,10 @@ namespace build2
                 const path_type& t,
                 timestamp e)
   {
-    timestamp t_mt (file_mtime (t));
-    timestamp d_mt (file_mtime (d));
+    using build2::mtime;
+
+    timestamp t_mt (mtime (t));
+    timestamp d_mt (mtime (d));
 
     if (d_mt > t_mt)
     {
diff --git a/build2/depdb.hxx b/build2/depdb.hxx
index f1e86a1..64ea627 100644
--- a/build2/depdb.hxx
+++ b/build2/depdb.hxx
@@ -12,9 +12,8 @@
 
 namespace build2
 {
-  // Auxiliary dependency database (those .d files). Uses io_error and
-  // system_error exceptions to signal errors except for openning (see
-  // below).
+  // Auxiliary dependency database (those .d files). Prints the diagnostics
+  // and fails on system and IO errors.
   //
   // This is a strange beast: a line-oriented, streaming database that can, at
   // some point, be switched from reading to (over)writing. The idea is to
@@ -95,11 +94,10 @@ namespace build2
     // has wrong format version, or is corrupt, then the database will be
     // immediately switched to writing.
     //
-    // If the database cannot be opened, issue diagnostics and throw failed.
-    // This commonly happens when the user tries to stash the target in a
-    // non-existent subdirectory but forgets to add the corresponding fsdir{}
-    // prerequisite. Handling this as io_error in every rule that uses depdb
-    // would be burdensome thus we issue the diagnostics here.
+    // The failure commonly happens when the user tries to stash the target in
+    // a non-existent subdirectory but forgets to add the corresponding fsdir{}
+    // prerequisite. That's why the issued diagnostics may provide the
+    // corresponding hint.
     //
     explicit
     depdb (path_type);
diff --git a/build2/filesystem.cxx b/build2/filesystem.cxx
index 97f540b..5e6df5f 100644
--- a/build2/filesystem.cxx
+++ b/build2/filesystem.cxx
@@ -27,6 +27,20 @@ namespace build2
     }
   }
 
+  timestamp
+  mtime (const char* p)
+  {
+    try
+    {
+      return file_mtime (p);
+    }
+    catch (const system_error& e)
+    {
+      fail << "unable to obtain file " << p << " modification time: " << e
+           << endf;
+    }
+  }
+
   fs_status<mkdir_status>
   mkdir (const dir_path& d, uint16_t v)
   {
diff --git a/build2/filesystem.hxx b/build2/filesystem.hxx
index ccc5a73..ed99685 100644
--- a/build2/filesystem.hxx
+++ b/build2/filesystem.hxx
@@ -38,6 +38,19 @@ namespace build2
   bool
   touch (const path&, bool create, uint16_t verbosity = 1);
 
+  // Return the modification time for an existing regular file and
+  // timestamp_nonexistent otherwise. Print the diagnostics and fail on system
+  // error.
+  //
+  timestamp
+  mtime (const char*);
+
+  inline timestamp
+  mtime (const path& p)
+  {
+    return mtime (p.string ().c_str ());
+  }
+
   // Create the directory and print the standard diagnostics starting from
   // the specified verbosity level.
   //
diff --git a/build2/rule.cxx b/build2/rule.cxx
index b702bab..2a10a90 100644
--- a/build2/rule.cxx
+++ b/build2/rule.cxx
@@ -83,7 +83,7 @@ namespace build2
           p = &pt->derive_path ();
         }
 
-        ts = file_mtime (*p);
+        ts = mtime (*p);
         pt->mtime (ts);
 
         if (ts != timestamp_unknown && ts != timestamp_nonexistent)
diff --git a/build2/search.cxx b/build2/search.cxx
index c4b9ae3..7683ef6 100644
--- a/build2/search.cxx
+++ b/build2/search.cxx
@@ -4,11 +4,10 @@
 
 #include <build2/search.hxx>
 
-#include <libbutl/filesystem.mxx> // file_mtime()
-
 #include <build2/scope.hxx>
 #include <build2/target.hxx>
 #include <build2/context.hxx>
+#include <build2/filesystem.hxx>   // mtime()
 #include <build2/prerequisite.hxx>
 #include <build2/diagnostics.hxx>
 
@@ -148,7 +147,7 @@ namespace build2
       f += *ext;
     }
 
-    timestamp mt (file_mtime (f));
+    timestamp mt (mtime (f));
 
     if (mt == timestamp_nonexistent)
     {
diff --git a/build2/target.cxx b/build2/target.cxx
index b8e2a60..667933a 100644
--- a/build2/target.cxx
+++ b/build2/target.cxx
@@ -4,8 +4,6 @@
 
 #include <build2/target.hxx>
 
-#include <libbutl/filesystem.mxx> // file_mtime()
-
 #include <build2/file.hxx>
 #include <build2/scope.hxx>
 #include <build2/search.hxx>
diff --git a/build2/target.ixx b/build2/target.ixx
index c3e2f63..dcbea32 100644
--- a/build2/target.ixx
+++ b/build2/target.ixx
@@ -4,6 +4,8 @@
 
 #include <cstring> // memcpy()
 
+#include <build2/filesystem.hxx> // mtime()
+
 namespace build2
 {
   // target
@@ -314,7 +316,7 @@ namespace build2
     {
       assert (!p.empty ());
 
-      r = file_mtime (p).time_since_epoch ().count ();
+      r = build2::mtime (p).time_since_epoch ().count ();
       mtime_.store (r, memory_order_release);
     }
 
diff --git a/build2/test/script/builtin.cxx b/build2/test/script/builtin.cxx
index 657d8d4..e4eb895 100644
--- a/build2/test/script/builtin.cxx
+++ b/build2/test/script/builtin.cxx
@@ -996,7 +996,7 @@ namespace build2
               check_wd (from);
               check_wd (to);
 
-              bool exists (entry_exists (to));
+              bool exists (butl::entry_exists (to));
 
               // Fail if the source and destination paths are the same.
               //