* `nix-store --gc' prints out the number of bytes freed on stdout

  (even when it is interrupted by a signal).

7 files changed, 45 insertions, 11 deletions

diff --git a/src/libstore/gc.cc b/src/libstore/gc.cc
index bdaf2946ca58..cb808b6d1b68 100644
--- a/src/libstore/gc.cc
+++ b/src/libstore/gc.cc
@@ -303,9 +303,11 @@ static Paths topoSort(const PathSet & paths)
 }
 
 
-void collectGarbage(GCAction action, PathSet & result)
+void collectGarbage(GCAction action, PathSet & result,
+    unsigned long long & bytesFreed)
 {
     result.clear();
+    bytesFreed = 0;
 
     bool gcKeepOutputs =
         queryBoolSetting("gc-keep-outputs", false);
@@ -452,7 +454,9 @@ void collectGarbage(GCAction action, PathSet & result)
             printMsg(lvlInfo, format("deleting `%1%'") % *i);
             
             /* Okay, it's safe to delete. */
-            deleteFromStore(*i);
+            unsigned long long freed;
+            deleteFromStore(*i, freed);
+            bytesFreed += freed;
 
             if (fdLock != -1)
                 /* Write token to stale (deleted) lock file. */
diff --git a/src/libstore/gc.hh b/src/libstore/gc.hh
index b6a367c4b330..eb1858729037 100644
--- a/src/libstore/gc.hh
+++ b/src/libstore/gc.hh
@@ -19,7 +19,8 @@ typedef enum {
    closure of) the roots.  If `action' is `gcReturnDead', return the
    set of paths not reachable from the roots.  If `action' is
    `gcDeleteDead', actually delete the latter set. */
-void collectGarbage(GCAction action, PathSet & result);
+void collectGarbage(GCAction action, PathSet & result,
+    unsigned long long & bytesFreed);
 
 /* Register a temporary GC root.  This root will automatically
    disappear when this process exits.  WARNING: this function should
diff --git a/src/libstore/store.cc b/src/libstore/store.cc
index 281ccc4bf147..dc3625a1d5da 100644
--- a/src/libstore/store.cc
+++ b/src/libstore/store.cc
@@ -746,8 +746,9 @@ Path addTextToStore(const string & suffix, const string & s,
 }
 
 
-void deleteFromStore(const Path & _path)
+void deleteFromStore(const Path & _path, unsigned long long & bytesFreed)
 {
+    bytesFreed = 0;
     Path path(canonPath(_path));
 
     assertStorePath(path);
@@ -763,7 +764,7 @@ void deleteFromStore(const Path & _path)
     }
     txn.commit();
 
-    deletePath(path);
+    deletePath(path, bytesFreed);
 }
 
 
diff --git a/src/libstore/store.hh b/src/libstore/store.hh
index 0f35ff0c626c..2d8018d5fabc 100644
--- a/src/libstore/store.hh
+++ b/src/libstore/store.hh
@@ -155,7 +155,7 @@ Path addTextToStore(const string & suffix, const string & s,
     const PathSet & references);
 
 /* Delete a value from the nixStore directory. */
-void deleteFromStore(const Path & path);
+void deleteFromStore(const Path & path, unsigned long long & bytesFreed);
 
 void verifyStore(bool checkContents);
 
diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index 2e684e9c1441..5a728617dbd4 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -194,7 +194,7 @@ void writeFile(const Path & path, const string & s)
 }
 
 
-static void _deletePath(const Path & path)
+static void _deletePath(const Path & path, unsigned long long & bytesFreed)
 {
     checkInterrupt();
 
@@ -204,6 +204,8 @@ static void _deletePath(const Path & path)
     if (lstat(path.c_str(), &st))
 	throw SysError(format("getting attributes of path `%1%'") % path);
 
+    bytesFreed += st.st_size;
+
     if (S_ISDIR(st.st_mode)) {
 	Strings names = readDirectory(path);
 
@@ -214,7 +216,7 @@ static void _deletePath(const Path & path)
 	}
 
 	for (Strings::iterator i = names.begin(); i != names.end(); ++i)
-            _deletePath(path + "/" + *i);
+            _deletePath(path + "/" + *i, bytesFreed);
     }
 
     if (remove(path.c_str()) == -1)
@@ -224,9 +226,17 @@ static void _deletePath(const Path & path)
 
 void deletePath(const Path & path)
 {
+    unsigned long long dummy;
+    deletePath(path, dummy);
+}
+
+
+void deletePath(const Path & path, unsigned long long & bytesFreed)
+{
     startNest(nest, lvlDebug,
         format("recursively deleting path `%1%'") % path);
-    _deletePath(path);
+    bytesFreed = 0;
+    _deletePath(path, bytesFreed);
 }
 
 
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index 9e7eb11bd16d..9601e65b3c63 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -98,9 +98,12 @@ string readFile(const Path & path);
 void writeFile(const Path & path, const string & s);
 
 /* Delete a path; i.e., in the case of a directory, it is deleted
-   recursively.  Don't use this at home, kids. */
+   recursively.  Don't use this at home, kids.  The second variant
+   returns the number of bytes freed. */
 void deletePath(const Path & path);
 
+void deletePath(const Path & path, unsigned long long & bytesFreed);
+
 /* Make a path read-only recursively. */
 void makePathReadOnly(const Path & path);
 
diff --git a/src/nix-store/main.cc b/src/nix-store/main.cc
index d1a96aa3a9ef..8bb1b1254365 100644
--- a/src/nix-store/main.cc
+++ b/src/nix-store/main.cc
@@ -489,6 +489,20 @@ static void opCheckValidity(Strings opFlags, Strings opArgs)
 }
 
 
+struct PrintFreed 
+{
+    bool show;
+    unsigned long long bytesFreed;
+    PrintFreed(bool _show) : bytesFreed(0), show(_show) { }
+    ~PrintFreed() 
+    {
+        if (show)
+            cout << format("%d bytes freed (%.2f MiB)\n")
+                % bytesFreed % (bytesFreed / (1024.0 * 1024.0));
+    }
+};
+
+
 static void opGC(Strings opFlags, Strings opArgs)
 {
     GCAction action = gcDeleteDead;
@@ -503,7 +517,8 @@ static void opGC(Strings opFlags, Strings opArgs)
         else throw UsageError(format("bad sub-operation `%1%' in GC") % *i);
 
     PathSet result;
-    collectGarbage(action, result);
+    PrintFreed freed(action == gcDeleteDead);
+    collectGarbage(action, result, freed.bytesFreed);
 
     if (action != gcDeleteDead) {
         for (PathSet::iterator i = result.begin(); i != result.end(); ++i)