Parse Checksum fields via pkgTagSection::Key, too

We abstract hashes a fair bit to be able to add new ones eventually,
which lead us to building the field names on the fly. We can do better
through by keeping a central place for these names, too, which even
helps in reducing code as we don't need the MD5 → Files dance anymore.

8 files changed, 48 insertions, 41 deletions

diff --git a/apt-pkg/contrib/hashes.cc b/apt-pkg/contrib/hashes.cc
index 267e2679a..313b1d37d 100644
--- a/apt-pkg/contrib/hashes.cc
+++ b/apt-pkg/contrib/hashes.cc
@@ -17,6 +17,8 @@
 #include <apt-pkg/hashes.h>
 #include <apt-pkg/macros.h>
 #include <apt-pkg/strutl.h>
+#include <apt-pkg/tagfile-keys.h>
+#include <apt-pkg/tagfile.h>
 
 #include <algorithm>
 #include <iostream>
@@ -45,6 +47,15 @@ const char * HashString::_SupportedHashes[] =
 {
    "SHA512", "SHA256", "SHA1", "MD5Sum", "Checksum-FileSize", NULL
 };
+std::vector<HashString::HashSupportInfo> HashString::SupportedHashesInfo()
+{
+   return {{
+      { "SHA512",  pkgTagSection::Key::SHA512,"Checksums-Sha512", pkgTagSection::Key::Checksums_Sha512},
+      { "SHA256", pkgTagSection::Key::SHA256, "Checksums-Sha256", pkgTagSection::Key::Checksums_Sha256},
+      { "SHA1", pkgTagSection::Key::SHA1, "Checksums-Sha1", pkgTagSection::Key::Checksums_Sha1 },
+      { "MD5Sum", pkgTagSection::Key::MD5sum, "Files", pkgTagSection::Key::Files },
+   }};
+}
 
 HashString::HashString()
 {
diff --git a/apt-pkg/contrib/hashes.h b/apt-pkg/contrib/hashes.h
index 422c1e023..e259b4e28 100644
--- a/apt-pkg/contrib/hashes.h
+++ b/apt-pkg/contrib/hashes.h
@@ -14,6 +14,11 @@
 
 #include <apt-pkg/macros.h>
 
+#ifdef APT_COMPILING_APT
+#include <apt-pkg/string_view.h>
+#include <apt-pkg/tagfile-keys.h>
+#endif
+
 #include <cstring>
 #include <string>
 #include <vector>
@@ -59,6 +64,15 @@ class APT_PUBLIC HashString
 
    // return the list of hashes we support
    static APT_PURE const char** SupportedHashes();
+#ifdef APT_COMPILING_APT
+   struct APT_HIDDEN HashSupportInfo {
+      APT::StringView name;
+      pkgTagSection::Key namekey;
+      APT::StringView chksumsname;
+      pkgTagSection::Key chksumskey;
+   };
+   APT_HIDDEN static std::vector<HashSupportInfo> SupportedHashesInfo();
+#endif
 };
 
 class APT_PUBLIC HashStringList
diff --git a/apt-pkg/deb/debmetaindex.cc b/apt-pkg/deb/debmetaindex.cc
index 32f1fa8db..c6005f1c8 100644
--- a/apt-pkg/deb/debmetaindex.cc
+++ b/apt-pkg/deb/debmetaindex.cc
@@ -515,10 +515,9 @@ bool debReleaseIndex::Load(std::string const &Filename, std::string * const Erro
 
    bool FoundHashSum = false;
    bool FoundStrongHashSum = false;
-   auto const SupportedHashes = HashString::SupportedHashes();
-   for (int i=0; SupportedHashes[i] != NULL; i++)
+   for (auto const hashinfo : HashString::SupportedHashesInfo())
    {
-      if (!Section.Find(SupportedHashes[i], Start, End))
+      if (not Section.Find(hashinfo.namekey, Start, End))
 	 continue;
 
       std::string Name;
@@ -529,7 +528,7 @@ bool debReleaseIndex::Load(std::string const &Filename, std::string * const Erro
 	 if (!parseSumData(Start, End, Name, Hash, Size))
 	    return false;
 
-	 HashString const hs(SupportedHashes[i], Hash);
+	 HashString const hs(hashinfo.name.to_string(), Hash);
          if (Entries.find(Name) == Entries.end())
          {
             metaIndex::checkSum *Sum = new metaIndex::checkSum;
diff --git a/apt-pkg/deb/debsrcrecords.cc b/apt-pkg/deb/debsrcrecords.cc
index 1fd0fdc12..311bacfdd 100644
--- a/apt-pkg/deb/debsrcrecords.cc
+++ b/apt-pkg/deb/debsrcrecords.cc
@@ -172,26 +172,19 @@ bool debSrcRecordParser::Files(std::vector<pkgSrcRecords::File> &List)
    std::vector<std::string> const compExts = APT::Configuration::getCompressorExtensions();
 
    auto const &posix = std::locale::classic();
-   for (char const * const * type = HashString::SupportedHashes(); *type != NULL; ++type)
+   for (auto const hashinfo : HashString::SupportedHashesInfo())
    {
-      // derive field from checksum type
-      std::string checksumField("Checksums-");
-      if (strcmp(*type, "MD5Sum") == 0)
-	 checksumField = "Files"; // historic name for MD5 checksums
-      else
-	 checksumField.append(*type);
-
-      string const Files = Sect.FindS(checksumField.c_str());
+      auto const Files = Sect.Find(hashinfo.chksumskey);
       if (Files.empty() == true)
 	 continue;
-      std::istringstream ss(Files);
+      std::istringstream ss(Files.to_string());
       ss.imbue(posix);
 
       while (ss.good())
       {
 	 std::string hash, path;
 	 unsigned long long size;
-	 if (iIndex == nullptr && checksumField == "Files")
+	 if (iIndex == nullptr && hashinfo.chksumskey == pkgTagSection::Key::Files)
 	 {
 	    std::string ignore;
 	    ss >> hash >> size >> ignore >> ignore >> path;
@@ -200,9 +193,9 @@ bool debSrcRecordParser::Files(std::vector<pkgSrcRecords::File> &List)
 	    ss >> hash >> size >> path;
 
 	 if (ss.fail() || hash.empty() || path.empty())
-	    return _error->Error("Error parsing file record in %s of source package %s", checksumField.c_str(), Package().c_str());
+	    return _error->Error("Error parsing file record in %s of source package %s", hashinfo.chksumsname.to_string().c_str(), Package().c_str());
 
-	 HashString const hashString(*type, hash);
+	 HashString const hashString(hashinfo.name.to_string(), hash);
 	 if (Base.empty() == false)
 	    path = Base + path;
 
@@ -217,7 +210,7 @@ bool debSrcRecordParser::Files(std::vector<pkgSrcRecords::File> &List)
 	 {
 	    // an error here indicates that we have two different hashes for the same file
 	    if (file->Hashes.push_back(hashString) == false)
-	       return _error->Error("Error parsing checksum in %s of source package %s", checksumField.c_str(), Package().c_str());
+	       return _error->Error("Error parsing checksum in %s of source package %s", hashinfo.chksumsname.to_string().c_str(), Package().c_str());
 	    continue;
 	 }
 
diff --git a/apt-pkg/indexcopy.cc b/apt-pkg/indexcopy.cc
index 82baba337..0d569265d 100644
--- a/apt-pkg/indexcopy.cc
+++ b/apt-pkg/indexcopy.cc
@@ -437,22 +437,14 @@ bool PackageCopy::RewriteEntry(FileFd &Target,string const &File)
 /* */
 bool SourceCopy::GetFile(string &File,unsigned long long &Size)
 {
-   string Files;
-
-   for (char const *const *type = HashString::SupportedHashes(); *type != NULL; ++type)
+   std::string Files;
+   for (auto hashinfo : HashString::SupportedHashesInfo())
    {
-      // derive field from checksum type
-      std::string checksumField("Checksums-");
-      if (strcmp(*type, "MD5Sum") == 0)
-	 checksumField = "Files"; // historic name for MD5 checksums
-      else
-	 checksumField.append(*type);
-
-      Files = Section->FindS(checksumField);
-      if (Files.empty() == false)
+      Files = Section->Find(hashinfo.chksumskey).to_string();
+      if (not Files.empty())
 	 break;
    }
-   if (Files.empty() == true)
+   if (Files.empty())
       return false;
 
    // Read the first file triplet
diff --git a/apt-private/private-show.cc b/apt-private/private-show.cc
index 46c4c35e7..08a4fe6df 100644
--- a/apt-private/private-show.cc
+++ b/apt-private/private-show.cc
@@ -260,10 +260,8 @@ static bool DisplayRecordV2(pkgCacheFile &CacheFile, pkgRecords &Recs, /*{{{*/
    // delete, apt-cache show has this info and most users do not care
    if (not _config->FindB("APT::Cache::ShowFull", false))
    {
-      RW.push_back(pkgTagSection::Tag::Remove("MD5sum"));
-      RW.push_back(pkgTagSection::Tag::Remove("SHA1"));
-      RW.push_back(pkgTagSection::Tag::Remove("SHA256"));
-      RW.push_back(pkgTagSection::Tag::Remove("SHA512"));
+      for (char const * const * type = HashString::SupportedHashes(); *type != nullptr; ++type)
+	 RW.push_back(pkgTagSection::Tag::Remove(*type));
       RW.push_back(pkgTagSection::Tag::Remove("Filename"));
       RW.push_back(pkgTagSection::Tag::Remove("Multi-Arch"));
       RW.push_back(pkgTagSection::Tag::Remove("Conffiles"));
diff --git a/ftparchive/writer.cc b/ftparchive/writer.cc
index c786be6ac..ae427b120 100644
--- a/ftparchive/writer.cc
+++ b/ftparchive/writer.cc
@@ -771,21 +771,21 @@ bool SourcesWriter::DoPackage(string FileName)
 	 {
 	    if (hs->HashType() == "MD5Sum" || hs->HashType() == "Checksum-FileSize")
 	       continue;
-	    char const * fieldname;
+	    pkgTagSection::Key fieldkey;
 	    std::string * out;
 	    if (hs->HashType() == "SHA1")
 	    {
-	       fieldname = "Checksums-Sha1";
+	       fieldkey = pkgTagSection::Key::Checksums_Sha1;
 	       out = &ChecksumsSha1;
 	    }
 	    else if (hs->HashType() == "SHA256")
 	    {
-	       fieldname = "Checksums-Sha256";
+	       fieldkey = pkgTagSection::Key::Checksums_Sha256;
 	       out = &ChecksumsSha256;
 	    }
 	    else if (hs->HashType() == "SHA512")
 	    {
-	       fieldname = "Checksums-Sha512";
+	       fieldkey = pkgTagSection::Key::Checksums_Sha512;
 	       out = &ChecksumsSha512;
 	    }
 	    else
@@ -793,7 +793,7 @@ bool SourcesWriter::DoPackage(string FileName)
 	       _error->Warning("Ignoring unknown Checksumtype %s in SourcesWriter::DoPackages", hs->HashType().c_str());
 	       continue;
 	    }
-	    if (Tags.Exists(fieldname) == true)
+	    if (Tags.Exists(fieldkey))
 	       continue;
 	    std::ostringstream streamout;
 	    streamout << "\n " << hs->HashValue() << " " << std::to_string(Db.GetFileSize()) << " " << ParseJnk;
diff --git a/test/integration/test-ubuntu-bug-1098738-apt-get-source-md5sum b/test/integration/test-ubuntu-bug-1098738-apt-get-source-md5sum
index f0a8835a2..6a66094de 100755
--- a/test/integration/test-ubuntu-bug-1098738-apt-get-source-md5sum
+++ b/test/integration/test-ubuntu-bug-1098738-apt-get-source-md5sum
@@ -441,4 +441,4 @@ testnohash pkg-md5-agree
 testfailureequal 'Reading package lists...
 E: Error parsing checksum in Files of source package pkg-md5-disagree' aptget source -d pkg-md5-disagree
 testfailureequal 'Reading package lists...
-E: Error parsing checksum in Checksums-SHA256 of source package pkg-sha256-disagree' aptget source -d pkg-sha256-disagree
+E: Error parsing checksum in Checksums-Sha256 of source package pkg-sha256-disagree' aptget source -d pkg-sha256-disagree