Add support for checked out repository fragments caching

1 files changed, 62 insertions, 2 deletions

diff --git a/bpkg/pkg-checkout.hxx b/bpkg/pkg-checkout.hxx
index 3a058b5..d910509 100644
--- a/bpkg/pkg-checkout.hxx
+++ b/bpkg/pkg-checkout.hxx
@@ -4,6 +4,8 @@
 #ifndef BPKG_PKG_CHECKOUT_HXX
 #define BPKG_PKG_CHECKOUT_HXX
 
+#include <map>
+
 #include <libbpkg/manifest.hxx>     // version
 #include <libbpkg/package-name.hxx>
 
@@ -18,13 +20,70 @@ namespace bpkg
   int
   pkg_checkout (const pkg_checkout_options&, cli::scanner& args);
 
+  // Checked out repository fragments cache.
+  //
+  // Needs to be passed to pkg_checkout() calls.
+  //
+  class pkg_checkout_cache
+  {
+  public:
+    // The options reference is assumed to be valid till the end of the cache
+    // object lifetime.
+    //
+    pkg_checkout_cache (const common_options& o): options_ (o) {}
+
+    // Restore the cached repositories in their permanent locations (move back
+    // from the temporary directory, fixup, etc) and erase the entries.
+    //
+    // Note that the destructor will clear the cache but will ignore any
+    // errors. To detect such errors, call clear() explicitly.
+    //
+    bool
+    clear (bool ignore_errors = false);
+
+    // Call clear() in the ignore errors mode and issue the "repository is now
+    // broken" warning on failure.
+    //
+    ~pkg_checkout_cache ();
+
+    // pkg_checkout () implementation details.
+    //
+  public:
+    struct state
+    {
+      auto_rmdir rmt;         // The repository temporary directory.
+      repository_location rl; // The repository location.
+
+      // nullopt if the repository fragment checkout failed in the middle and
+      // the repository cannot be restored in its permanent location (we will
+      // call such entry incomplete). True if the repository directory was
+      // fixed up.
+      //
+      optional<bool> fixedup;
+    };
+
+    using state_map = std::map<dir_path, state>;
+
+    state_map map_;
+    const common_options& options_;
+
+    // Restore the repository in its permanent location and erase the cache
+    // entry. On error issue diagnostics and return false in the ignore errors
+    // mode and throw failed otherwise. Note that erasing an incomplete entry
+    // is an error.
+    //
+    bool
+    erase (state_map::iterator, bool ignore_errors = false);
+  };
+
   // Check out the package from a version control-based repository into a
   // directory other than the configuration directory and commit the
   // transaction. Return the selected package object which may replace the
   // existing one.
   //
   shared_ptr<selected_package>
-  pkg_checkout (const common_options&,
+  pkg_checkout (pkg_checkout_cache&,
+                const common_options&,
                 database&,
                 transaction&,
                 package_name,
@@ -39,7 +98,8 @@ namespace bpkg
   // existing one.
   //
   shared_ptr<selected_package>
-  pkg_checkout (const common_options&,
+  pkg_checkout (pkg_checkout_cache&,
+                const common_options&,
                 database&,
                 transaction&,
                 package_name,