2 files changed, 25 insertions, 0 deletions
diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index 4d82547c621d..f93ba36395ac 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -327,6 +327,8 @@ void LocalStore::openDB(bool create)
         "insert into FailedPaths (path, time) values (?, ?);");
     stmtHasPathFailed.create(db,
         "select time from FailedPaths where path = ?;");
+    stmtQueryFailedPaths.create(db,
+        "select path from FailedPaths;");
     stmtAddDerivationOutput.create(db,
         "insert or replace into DerivationOutputs (drv, id, path) values (?, ?, ?);");
     stmtQueryValidDerivers.create(db,
@@ -508,6 +510,25 @@ bool LocalStore::hasPathFailed(const Path & path)
 }
 
 
+PathSet LocalStore::queryFailedPaths()
+{
+    SQLiteStmtUse use(stmtQueryFailedPaths);
+
+    PathSet res;
+    int r;
+    while ((r = sqlite3_step(stmtQueryFailedPaths)) == SQLITE_ROW) {
+        const char * s = (const char *) sqlite3_column_text(stmtQueryFailedPaths, 0);
+        assert(s);
+        res.insert(s);
+    }
+
+    if (r != SQLITE_DONE)
+        throw SQLiteError(db, "error querying failed paths");
+
+    return res;
+}
+
+
 Hash parseHashField(const Path & path, const string & s)
 {
     string::size_type colon = s.find(':');
diff --git a/src/libstore/local-store.hh b/src/libstore/local-store.hh
index 0c5f04158e65..70fc64fdc57f 100644
--- a/src/libstore/local-store.hh
+++ b/src/libstore/local-store.hh
@@ -184,6 +184,9 @@ public:
     /* Query whether `path' previously failed to build. */
     bool hasPathFailed(const Path & path);
 
+    /* Return the set of paths that have failed to build.*/
+    PathSet queryFailedPaths();
+
 private:
 
     Path schemaPath;
@@ -203,6 +206,7 @@ private:
     SQLiteStmt stmtInvalidatePath;
     SQLiteStmt stmtRegisterFailedPath;
     SQLiteStmt stmtHasPathFailed;
+    SQLiteStmt stmtQueryFailedPaths;
     SQLiteStmt stmtAddDerivationOutput;
     SQLiteStmt stmtQueryValidDerivers;
     SQLiteStmt stmtQueryDerivationOutputs;