functional but naive activate command

src/bottles/activate.cpp

@@ -1,12 +1,43 @@
+#include <cstdlib>
 #include <iostream>
 #include <string>
 #include <vector>
 
+#include <boost/filesystem/operations.hpp>
+#include <boost/filesystem/path.hpp>
+
 #include "bottles.hpp"
 #include "internal/bottles.hpp"
 
 using namespace std;
+using namespace boost::filesystem;
 
 void cellar::bottles::switch_active_bottle(int argc, vector<string> argv) {
-    cout << argv[0] << endl;
+    if (argc == 1) {
+        cout << "forgot to specify a bottle to activate" << endl;
+        return;
+    }
+
+    string homepath = getenv("HOME");                // /home/nick
+    string bottlepath = homepath + "/.wine";         // /home/nick/.wine
+    string targetpath = bottlepath + "." + argv[1];  // /home/nick/.wine.example
+
+    file_status targetstatus = symlink_status(targetpath);
+    if (!exists(targetstatus)) {
+        cerr << "target " << targetpath << " does not exist" << endl;
+        return;
+    }
+
+    file_status bottlestatus = symlink_status(bottlepath);
+    if (exists(bottlestatus)) {
+        bool bottlesymlink = is_symlink(bottlestatus);
+        if (!bottlesymlink) {
+            cerr << "refusing to clobber " << bottlepath << ": not a symlink" << endl;
+            return;
+        }
+        remove(bottlepath);
+    }
+
+    // TODO: not blindly assume this will magically work
+    create_symlink(targetpath, bottlepath);
 }