Add 'dist-clean' command to remove packages and list files

We assume all files in the 'listsdir' are candidates. Keep only files
ending with Release, Release.gpg, and InRelease.

Closes: #959093

5 files changed, 86 insertions, 18 deletions

diff --git a/apt-pkg/acquire.cc b/apt-pkg/acquire.cc
index cdb2c5257..727880e71 100644
--- a/apt-pkg/acquire.cc
+++ b/apt-pkg/acquire.cc
@@ -29,6 +29,7 @@
 #include <iostream>
 #include <memory>
 #include <numeric>
+#include <regex>
 #include <sstream>
 #include <string>
 #include <tuple>
@@ -825,11 +826,11 @@ pkgAcquire::Worker *pkgAcquire::WorkerStep(Worker *I)
    return I->NextAcquire;
 }
 									/*}}}*/
-// Acquire::Clean - Cleans a directory					/*{{{*/
+// Acquire::CleanDir - Cleans a directory					/*{{{*/
 // ---------------------------------------------------------------------
 /* This is a bit simplistic, it looks at every file in the dir and sees
-   if it is part of the download set. */
-bool pkgAcquire::Clean(string Dir)
+   if it matches the predicate or not. */
+bool pkgAcquire::CleanDir(string Dir, std::function<bool(char const*)> const &Keep, char const * const Caller)
 {
    // non-existing directories are by definition clean…
    if (DirectoryExists(Dir) == false)
@@ -853,22 +854,49 @@ bool pkgAcquire::Clean(string Dir)
 	  strcmp(E->d_name, "auxfiles") == 0 ||
 	  strcmp(E->d_name, "lost+found") == 0 ||
 	  strcmp(E->d_name, ".") == 0 ||
-	  strcmp(E->d_name, "..") == 0)
+	  strcmp(E->d_name, "..") == 0 ||
+	  Keep(E->d_name) == true)
 	 continue;
-
-      // Look in the get list and if not found nuke
-      if (std::any_of(Items.cbegin(), Items.cend(),
-	     [&E](pkgAcquire::Item const * const I) {
-		return flNotDir(I->DestFile) == E->d_name;
-	     }) == false)
-      {
-	 RemoveFileAt("pkgAcquire::Clean", dirfd, E->d_name);
-      }
+      RemoveFileAt(Caller, dirfd, E->d_name);
    }
    closedir(D);
    return true;
 }
 									/*}}}*/
+// Acquire::Clean - Cleans a directory of downloaded files             /*{{{*/
+// ---------------------------------------------------------------------
+/* This is a bit simplistic, it looks at every file in the dir and sees
+   if it is part of the download set. */
+bool pkgAcquire::Clean(string Dir)
+{
+   return CleanDir(
+      Dir,
+      // Look in the get list and if found then keep
+      [this](char const *FName) {
+         return std::any_of(Items.cbegin(), Items.cend(),
+            [FName](pkgAcquire::Item const * const I) {
+               return flNotDir(I->DestFile) == FName;
+            });
+      },
+      "pkgAcquire::Clean"
+   );
+}
+                           /*}}}*/
+// Acquire::CleanLists - Cleans a directory of list files             /*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool pkgAcquire::CleanLists(string Dir)
+{
+   return CleanDir(
+      Dir,
+      [](char const *FName) noexcept {
+         static const std::regex KeepPattern(".*_(Release|Release.gpg|InRelease)");
+         return std::regex_match(FName, KeepPattern);
+      },
+      "pkgAcquire::CleanLists"
+   );
+}
+                           /*}}}*/
 // Acquire::TotalNeeded - Number of bytes to fetch			/*{{{*/
 // ---------------------------------------------------------------------
 /* This is the total number of bytes needed */
diff --git a/apt-pkg/acquire.h b/apt-pkg/acquire.h
index 17b68768e..46115a27f 100644
--- a/apt-pkg/acquire.h
+++ b/apt-pkg/acquire.h
@@ -70,6 +70,7 @@
 #include <apt-pkg/weakptr.h>
 
 #include <chrono>
+#include <functional>
 #include <string>
 #include <vector>
 
@@ -330,6 +331,14 @@ class APT_PUBLIC pkgAcquire
     *  \return \b true if the directory exists and is readable.
     */
    bool Clean(std::string Dir);
+   
+   /** Deletes each package list and index file in the given directory.
+    *
+    *  \param Dir The directory to be cleaned.
+    *
+    *  \return \b true if the directory exists and is readable.
+    */
+   bool CleanLists(std::string Dir);
 
    /** \return the total size in bytes of all the items included in
     *  this download.
@@ -372,6 +381,20 @@ class APT_PUBLIC pkgAcquire
 
    private:
    APT_HIDDEN void Initialize();
+
+   /** Delete each entry in the given directory whose name does \em not match
+    *  a criterion.
+    *
+    *  \param Dir The directory to be cleaned.
+    *
+    *  \param KeepP A predicate telling to keep the named file; if it is
+    *  non-empty and returns true, the file is kept.
+    *
+    *  \param Caller Log name of the caller.
+    *
+    *  \return \b true if the directory exists and is readable.
+    */
+   APT_HIDDEN static bool CleanDir(std::string Dir, std::function<bool(char const*)> const &KeepP, char const * const Caller);
 };
 
 /** \brief Represents a single download source from which an item
diff --git a/apt-private/private-download.cc b/apt-private/private-download.cc
index eddb901d0..b271ec03f 100644
--- a/apt-private/private-download.cc
+++ b/apt-private/private-download.cc
@@ -304,9 +304,20 @@ bool DoChangelog(CommandLine &CmdL)
 }
 									/*}}}*/
 
-// DoClean - Remove download archives					/*{{{*/
+// DoClean - Remove download archives            /*{{{*/
 bool DoClean(CommandLine &)
 {
+   return DoDistClean(false);
+}
+                           /*}}}*/
+// DoDistClean - Remove download archives and lists            /*{{{*/
+bool DoDistClean(CommandLine &)
+{
+   return DoDistClean(true);
+}
+// DoDistClean - the worker
+bool DoDistClean(bool ListsToo)
+{
    std::string const archivedir = _config->FindDir("Dir::Cache::archives");
    std::string const listsdir = _config->FindDir("Dir::state::lists");
 
@@ -315,23 +326,25 @@ bool DoClean(CommandLine &)
       std::string const pkgcache = _config->FindFile("Dir::cache::pkgcache");
       std::string const srcpkgcache = _config->FindFile("Dir::cache::srcpkgcache");
       std::cout << "Del " << archivedir << "* " << archivedir << "partial/*"<< std::endl
-	   << "Del " << listsdir << "partial/*" << std::endl
-	   << "Del " << pkgcache << " " << srcpkgcache << std::endl;
+      << "Del " << listsdir << "partial/*" << (ListsToo ? " *_{Packages,Sources}{,.diff_Index}" : "") << std::endl
+      << "Del " << pkgcache << " " << srcpkgcache << std::endl;
       return true;
    }
 
    pkgAcquire Fetcher;
    if (archivedir.empty() == false && FileExists(archivedir) == true &&
-	 Fetcher.GetLock(archivedir) == true)
+    Fetcher.GetLock(archivedir) == true)
    {
       Fetcher.Clean(archivedir);
       Fetcher.Clean(archivedir + "partial/");
    }
 
    if (listsdir.empty() == false && FileExists(listsdir) == true &&
-	 Fetcher.GetLock(listsdir) == true)
+    Fetcher.GetLock(listsdir) == true)
    {
       Fetcher.Clean(listsdir + "partial/");
+      if (ListsToo)
+         Fetcher.CleanLists(listsdir);
    }
 
    pkgCacheFile::RemoveCaches();
diff --git a/apt-private/private-download.h b/apt-private/private-download.h
index d829e8b24..918828241 100644
--- a/apt-private/private-download.h
+++ b/apt-private/private-download.h
@@ -33,6 +33,8 @@ APT_PUBLIC bool DoDownload(CommandLine &CmdL);
 APT_PUBLIC bool DoChangelog(CommandLine &CmdL);
 
 APT_PUBLIC bool DoClean(CommandLine &CmdL);
+APT_PUBLIC bool DoDistClean(CommandLine &CmdL);
+bool DoDistClean(bool ListsToo);
 APT_PUBLIC bool DoAutoClean(CommandLine &CmdL);
 
 #endif
diff --git a/cmdline/apt.cc b/cmdline/apt.cc
index f53d4e446..ef58bcebf 100644
--- a/cmdline/apt.cc
+++ b/cmdline/apt.cc
@@ -89,6 +89,8 @@ static std::vector<aptDispatchWithHelp> GetCommands()			/*{{{*/
       {"policy",&Policy, nullptr},
       {"build-dep", &DoBuildDep,nullptr},
       {"clean", &DoClean, nullptr},
+      {"distclean", &DoDistClean, nullptr},
+      {"dist-clean", &DoDistClean, nullptr},
       {"autoclean", &DoAutoClean, nullptr},
       {"auto-clean", &DoAutoClean, nullptr},
       {"source", &DoSource, nullptr},