Support local files as arguments in show command

Now that --with-source is supported in show we can go a little further
and add the "syntactic sugar" of supporting deb-files on the commandline
directly to give users an alternative to remembering dpkg -I for deb
files & as a bonus apt also works on changes files.

Most of the code churn is actually to deal with cases probably not too
common in reality like mixing packages and deb-files on the commandline
and getting the right order for these multiple records.

Closes: 883206

3 files changed, 101 insertions, 27 deletions

diff --git a/apt-private/private-install.cc b/apt-private/private-install.cc
index 4bb756b4f..f90e7097f 100644
--- a/apt-private/private-install.cc
+++ b/apt-private/private-install.cc
@@ -733,39 +733,54 @@ bool AddVolatileBinaryFile(pkgSourceList *const SL, PseudoPkg &&pkg, std::vector
    return true;
 }
 									/*}}}*/
-std::vector<PseudoPkg> GetPseudoPackages(pkgSourceList *const SL, CommandLine &CmdL, bool (*Add)(pkgSourceList *const, PseudoPkg &&, std::vector<PseudoPkg> &), std::string const &pseudoArch)/*{{{*/
+static bool AddIfVolatile(pkgSourceList *const SL, std::vector<PseudoPkg> &VolatileCmdL, bool (*Add)(pkgSourceList *const, PseudoPkg &&, std::vector<PseudoPkg> &), char const * const I, std::string const &pseudoArch)/*{{{*/
 {
-   std::vector<PseudoPkg> VolatileCmdL;
-   std::remove_if(CmdL.FileList + 1, CmdL.FileList + 1 + CmdL.FileSize(), [&](char const *const I) {
-      if (I != nullptr && (I[0] == '/' || (I[0] == '.' && (I[1] == '\0' || (I[1] == '.' && (I[2] == '\0' || I[2] == '/')) || I[1] == '/'))))
+   if (I != nullptr && (I[0] == '/' || (I[0] == '.' && (I[1] == '\0' || (I[1] == '.' && (I[2] == '\0' || I[2] == '/')) || I[1] == '/'))))
+   {
+      PseudoPkg pkg(I, pseudoArch, "", SL->GetVolatileFiles().size());
+      if (FileExists(I)) // this accepts directories and symlinks, too
+      {
+	 if (Add(SL, std::move(pkg), VolatileCmdL))
+	    ;
+	 else
+	    _error->Error(_("Unsupported file %s given on commandline"), I);
+	 return true;
+      }
+      else
       {
-	 PseudoPkg pkg(I, pseudoArch, "", SL->GetVolatileFiles().size());
-	 if (FileExists(I)) // this accepts directories and symlinks, too
+	 auto const found = pkg.name.rfind("/");
+	 if (found == pkg.name.find("/"))
+	    _error->Error(_("Unsupported file %s given on commandline"), I);
+	 else
 	 {
+	    pkg.release = pkg.name.substr(found + 1);
+	    pkg.name.erase(found);
 	    if (Add(SL, std::move(pkg), VolatileCmdL))
 	       ;
 	    else
 	       _error->Error(_("Unsupported file %s given on commandline"), I);
-	    return true;
-	 }
-	 else
-	 {
-	    auto const found = pkg.name.rfind("/");
-	    if (found == pkg.name.find("/"))
-	       _error->Error(_("Unsupported file %s given on commandline"), I);
-	    else
-	    {
-	       pkg.release = pkg.name.substr(found + 1);
-	       pkg.name.erase(found);
-	       if (Add(SL, std::move(pkg), VolatileCmdL))
-		  ;
-	       else
-		  _error->Error(_("Unsupported file %s given on commandline"), I);
-	    }
-	    return true;
 	 }
+	 return true;
       }
-      return false;
+   }
+   return false;
+}
+									/*}}}*/
+std::vector<PseudoPkg> GetAllPackagesAsPseudo(pkgSourceList *const SL, CommandLine &CmdL, bool (*Add)(pkgSourceList *const, PseudoPkg &&, std::vector<PseudoPkg> &), std::string const &pseudoArch)/*{{{*/
+{
+   std::vector<PseudoPkg> PkgCmdL;
+   std::for_each(CmdL.FileList + 1, CmdL.FileList + CmdL.FileSize(), [&](char const *const I) {
+      if (AddIfVolatile(SL, PkgCmdL, Add, I, pseudoArch) == false)
+	 PkgCmdL.emplace_back(I, pseudoArch, "", -1);
+   });
+   return PkgCmdL;
+}
+									/*}}}*/
+std::vector<PseudoPkg> GetPseudoPackages(pkgSourceList *const SL, CommandLine &CmdL, bool (*Add)(pkgSourceList *const, PseudoPkg &&, std::vector<PseudoPkg> &), std::string const &pseudoArch)/*{{{*/
+{
+   std::vector<PseudoPkg> VolatileCmdL;
+   std::remove_if(CmdL.FileList + 1, CmdL.FileList + 1 + CmdL.FileSize(), [&](char const *const I) {
+      return AddIfVolatile(SL, VolatileCmdL, Add, I, pseudoArch);
    });
    return VolatileCmdL;
 }
diff --git a/apt-private/private-install.h b/apt-private/private-install.h
index 07aa582be..39a040e7d 100644
--- a/apt-private/private-install.h
+++ b/apt-private/private-install.h
@@ -26,6 +26,7 @@ struct PseudoPkg
    PseudoPkg(std::string const &n, std::string const &a, std::string const &r) : name(n), arch(a), release(r), index(-1) {}
    PseudoPkg(std::string const &n, std::string const &a, std::string const &r, ssize_t i) : name(n), arch(a), release(r), index(i) {}
 };
+std::vector<PseudoPkg> GetAllPackagesAsPseudo(pkgSourceList *const SL, CommandLine &CmdL, bool (*Add)(pkgSourceList *const, PseudoPkg &&, std::vector<PseudoPkg> &), std::string const &pseudoArch);
 std::vector<PseudoPkg> GetPseudoPackages(pkgSourceList *const SL, CommandLine &CmdL, bool (*Add)(pkgSourceList *const, PseudoPkg &&, std::vector<PseudoPkg> &), std::string const &pseudoArch);
 bool AddVolatileBinaryFile(pkgSourceList *const SL, PseudoPkg &&pkg, std::vector<PseudoPkg> &VolatileCmdL);
 bool AddVolatileSourceFile(pkgSourceList *const SL, PseudoPkg &&pkg, std::vector<PseudoPkg> &VolatileCmdL);
diff --git a/apt-private/private-show.cc b/apt-private/private-show.cc
index 64251bed4..15c05d420 100644
--- a/apt-private/private-show.cc
+++ b/apt-private/private-show.cc
@@ -20,6 +20,7 @@
 
 #include <apt-private/private-cacheset.h>
 #include <apt-private/private-output.h>
+#include <apt-private/private-install.h>
 #include <apt-private/private-show.h>
 
 #include <ostream>
@@ -251,6 +252,8 @@ static bool DisplayRecordV2(pkgCacheFile &CacheFile, pkgRecords &Recs, /*{{{*/
 bool ShowPackage(CommandLine &CmdL)					/*{{{*/
 {
    pkgCacheFile CacheFile;
+   auto VolatileCmdL = GetAllPackagesAsPseudo(CacheFile.GetSourceList(), CmdL, AddVolatileBinaryFile, "");
+
    if (unlikely(CacheFile.GetPkgCache() == nullptr))
       return false;
    CacheSetHelperVirtuals helper(true, GlobalError::NOTICE);
@@ -258,7 +261,38 @@ bool ShowPackage(CommandLine &CmdL)					/*{{{*/
 			APT::CacheSetHelper::ALL : APT::CacheSetHelper::CANDIDATE;
    if (select == APT::CacheSetHelper::CANDIDATE && CacheFile.GetDepCache() == nullptr)
       return false;
-   APT::VersionList const verset = APT::VersionList::FromCommandLine(CacheFile, CmdL.FileList + 1, select, helper);
+
+   APT::VersionList verset;
+   size_t normalPackages = 0;
+   for (auto const &I: VolatileCmdL)
+   {
+      if (I.index == -1)
+      {
+	 APT::VersionContainerInterface::FromString(&verset, CacheFile, I.name, select, helper);
+	 ++normalPackages;
+      }
+      else
+      {
+	 if (select != APT::CacheSetHelper::CANDIDATE && unlikely(CacheFile.GetDepCache() == nullptr))
+	    return false;
+	 pkgCache::PkgIterator const P = CacheFile->FindPkg(I.name);
+	 if (unlikely(P.end()))
+	    continue;
+
+	 // Set any version providing the .deb as the candidate.
+	 for (auto Prv = P.ProvidesList(); Prv.end() == false; ++Prv)
+	 {
+	    if (I.release.empty())
+	       CacheFile->SetCandidateVersion(Prv.OwnerVer());
+	    else
+	       CacheFile->SetCandidateRelease(Prv.OwnerVer(), I.release);
+
+	    // via cacheset to have our usual handling
+	    APT::VersionContainerInterface::FromPackage(&verset, CacheFile, Prv.OwnerPkg(), APT::CacheSetHelper::CANDIDATE, helper);
+	 }
+      }
+   }
+
    int const ShowVersion = _config->FindI("APT::Cache::Show::Version", 1);
    pkgRecords Recs(CacheFile);
    for (APT::VersionList::const_iterator Ver = verset.begin(); Ver != verset.end(); ++Ver)
@@ -278,9 +312,33 @@ bool ShowPackage(CommandLine &CmdL)					/*{{{*/
 	 return false;
    }
 
-   if (select == APT::CacheSetHelper::CANDIDATE)
+   if (select == APT::CacheSetHelper::CANDIDATE && normalPackages != 0)
    {
-      APT::VersionList const verset_all = APT::VersionList::FromCommandLine(CacheFile, CmdL.FileList + 1, APT::CacheSetHelper::ALL, helper);
+      APT::VersionList verset_all;
+      for (auto const &I: VolatileCmdL)
+      {
+	 if (I.index == -1)
+	    APT::VersionContainerInterface::FromString(&verset_all, CacheFile, I.name, APT::CacheSetHelper::ALL, helper);
+	 else
+	 {
+	    pkgCache::PkgIterator const P = CacheFile->FindPkg(I.name);
+	    if (unlikely(P.end()))
+	       continue;
+
+	    // Set any version providing the .deb as the candidate.
+	    for (auto Prv = P.ProvidesList(); Prv.end() == false; ++Prv)
+	    {
+	       if (I.release.empty())
+		  CacheFile->SetCandidateVersion(Prv.OwnerVer());
+	       else
+		  CacheFile->SetCandidateRelease(Prv.OwnerVer(), I.release);
+
+	       // via cacheset to have our usual virtual handling
+	       APT::VersionContainerInterface::FromPackage(&verset_all, CacheFile, Prv.OwnerPkg(), APT::CacheSetHelper::CANDIDATE, helper);
+	    }
+	 }
+      }
+
       int const records = verset_all.size() - verset.size();
       if (records > 0)
          _error->Notice(P_("There is %i additional record. Please use the '-a' switch to see it", "There are %i additional records. Please use the '-a' switch to see them.", records), records);