Guess changelog URI for third-party sites

Contruct a changelog file path for third party sites that
do not use packages.debian.org/changelogs

This simply uses the ArchiveURI() of the source pkg and
looks for a .changelog file there.

LP: #563155

5 files changed, 114 insertions, 53 deletions

diff --git a/NEWS b/NEWS
index 9362657b..9af97aa6 100644
--- a/NEWS
+++ b/NEWS
@@ -126,6 +126,9 @@ behaviour is desirable for two reasons:
            in Debian Policy § 11.1 “Architecture specification
            strings”.
 
+  * [all]: Support downloading changelogs for packages on
+           third-party sites by guessing the URI. (LP: #563155)
+           
 - Minor bugs:
 
   * handle "-qq" like other apt-utils
diff --git a/src/cmdline/cmdline_changelog.cc b/src/cmdline/cmdline_changelog.cc
index 966b9273..370301af 100644
--- a/src/cmdline/cmdline_changelog.cc
+++ b/src/cmdline/cmdline_changelog.cc
@@ -230,7 +230,7 @@ void set_name(temp::name n, temp::name *target)
                                                                    term_metrics);
 
     boost::shared_ptr<aptitude::apt::changelog_info>
-      info = aptitude::apt::changelog_info::create(srcpkg, ver, section, name);
+      info = aptitude::apt::changelog_info::guess(srcpkg, ver, section, name);
 
     get_changelog(info,
 		  callbacks,
@@ -316,22 +316,6 @@ void do_cmdline_changelog(const vector<string> &packages,
 
 	  if(!ver.end())
 	    {
-	      // Move this to a central location and just display an
-	      // apt error?
-	      bool in_debian=false;
-
-	      for(pkgCache::VerFileIterator vf=ver.FileList();
-		  !vf.end() && !in_debian; ++vf)
-		if(!vf.File().end() && vf.File().Origin()!=NULL &&
-		   strcmp(vf.File().Origin(), "Debian")==0)
-		  in_debian=true;
-
-	      if(!in_debian)
-		{
-		  _error->Error(_("%s is not an official Debian package, cannot display its changelog."), input.c_str());
-		  continue;
-		}
-
               get_changelog(ver, filename, term_metrics);
 	    }
 	}
diff --git a/src/generic/apt/pkg_changelog.cc b/src/generic/apt/pkg_changelog.cc
index d425a260..192d3e56 100644
--- a/src/generic/apt/pkg_changelog.cc
+++ b/src/generic/apt/pkg_changelog.cc
@@ -85,15 +85,89 @@ namespace aptitude
       }
     }
 
+    std::string get_changelog_uri(const std::string &path)
+    {
+      string server = _config->Find("APT::Changelogs::Server",
+                                    "http://packages.debian.org/changelogs");
+
+      return cw::util::ssprintf("%s/%s/changelog",
+                                server.c_str(),
+                                path.c_str());
+    }
+
+    /* Construct a changelog file path for third party sites that do
+     * not use packages.debian.org/changelogs
+     * This simply uses the ArchiveURI() of the source pkg and looks for
+     * a .changelog file there.
+     */
+    bool guess_third_party_changelog_uri(pkgCache::VerIterator ver,
+                                         const std::string &path,
+                                         std::string &out_uri)
+    {
+      // guess uri for third-party packages
+      pkgCache::VerFileIterator vf = ver.FileList();
+      pkgCache::PkgFileIterator pf = vf.File();
+      pkgIndexFile *index;
+      if(apt_source_list->FindIndex(pf, index) == false)
+        return false;
+
+      out_uri = index->ArchiveURI(path + ".changelog");
+      return true;
+    }
+
     boost::shared_ptr<changelog_info>
     changelog_info::create(const std::string &source_package,
 			   const std::string &source_version,
-                           const std::string &path,
+                           const std::vector<std::string> &uri_list,
 			   const std::string &display_name)
     {
       return boost::make_shared<changelog_info>(source_package,
 						source_version,
-                                                path,
+                                                uri_list,
+						display_name);
+    }
+
+    boost::shared_ptr<changelog_info>
+    changelog_info::guess(const std::string &source_package,
+			  const std::string &source_version,
+                          const std::string &section,
+			  const std::string &display_name)
+    {
+      string realsection;
+      const string::size_type slashfound = section.find('/');
+      if(slashfound != section.npos)
+        realsection.assign(section, 0, slashfound);
+      else
+        realsection.assign("main");
+
+      string prefix;
+      if(source_package.size() > 3
+         && source_package.compare(0, 3, "lib") == 0)
+        prefix.assign(source_package, 0, 4);
+      else
+        prefix.assign(source_package, 0, 1);
+
+      string realver = StripEpoch(source_version);
+
+      vector<string> uri_list;
+
+      string path;
+      path = cw::util::ssprintf("pool/%s/%s/%s/%s_%s",
+                                realsection.c_str(),
+                                prefix.c_str(),
+                                source_package.c_str(),
+                                source_package.c_str(),
+                                realver.c_str());
+
+      uri_list.push_back(get_changelog_uri(path));
+
+      LOG_TRACE(Loggers::getAptitudeChangelog(),
+		"Getting the changelog of the source package "
+		<< source_package << " " << source_version);
+
+      return boost::make_shared<changelog_info>(source_package,
+						source_version,
+                                                uri_list,
 						display_name);
     }
 
@@ -123,14 +197,22 @@ namespace aptitude
       path = flNotFile(rec.FileName());
       path += source_package + "_" + StripEpoch(source_version);
 
+      vector<string> uri_list;
+
+      uri_list.push_back(get_changelog_uri(path));
+
+      string third_party_uri;
+      if(guess_third_party_changelog_uri(ver, path, third_party_uri))
+        uri_list.push_back(third_party_uri);
+
       LOG_TRACE(Loggers::getAptitudeChangelog(),
 		"For " << ver.ParentPkg().Name()
 		<< " " << ver.VerStr() << ", getting the changelog of the source package "
-		<< source_package << " " << source_version << " from " << path);
+		<< source_package << " " << source_version);
 
       return boost::make_shared<changelog_info>(source_package,
 						source_version,
-                                                path,
+                                                uri_list,
 						ver.ParentPkg().Name());
     }
 
@@ -391,8 +473,6 @@ namespace aptitude
 		   << req.get_info()->get_source_package()
 		   << ", source_version = "
 		   << req.get_info()->get_source_version()
-		   << ", path = "
-		   << req.get_info()->get_path()
 		   << ", display_name = "
 		   << req.get_info()->get_display_name()
 		   << ", download = 0x"
@@ -442,7 +522,7 @@ namespace aptitude
 
 	  const string source_package(info.get_source_package());
 	  const string source_version(info.get_source_version());
-          const string path(info.get_path());
+          const vector<string> uri_list(info.get_uri_list());
 	  const string name(info.get_display_name());
 	  const string short_description = cw::util::ssprintf(_("Changelog of %s"), name.c_str());
 
@@ -526,15 +606,17 @@ namespace aptitude
 		      }
 		}
 
-              string server = _config->Find("APT::Changelogs::Server",
-                                            "http://packages.debian.org/changelogs");
-              string uri = cw::util::ssprintf("%s/%s/changelog", server.c_str(), path.c_str());
-	      LOG_TRACE(logger,
-			"Adding " << uri
-			<< " as a URI for the changelog of " << source_package << " " << source_version);
-
-	      download.push_back(uri);
-
+              for(vector<string>::const_iterator uri = uri_list.begin();
+                  uri != uri_list.end();
+                  ++uri)
+                {
+                  LOG_TRACE(logger,
+                            "Adding " << (*uri)
+                            << " as a URI for the changelog of " << source_package
+                            << " " << source_version);
+
+                  download.push_back(*uri);
+                }
 
 	      LOG_TRACE(logger,
 			"Starting to download " << short_description);
diff --git a/src/generic/apt/pkg_changelog.h b/src/generic/apt/pkg_changelog.h
index a0748177..cf4ffa55 100644
--- a/src/generic/apt/pkg_changelog.h
+++ b/src/generic/apt/pkg_changelog.h
@@ -56,7 +56,7 @@ namespace aptitude
     {
       const std::string source_package;
       const std::string source_version;
-      const std::string path;
+      const std::vector<std::string> uri_list;
       const std::string display_name;
 
     public:
@@ -66,11 +66,11 @@ namespace aptitude
        */
       changelog_info(const std::string &_source_package,
 		     const std::string &_source_version,
-                     const std::string &_path,
+                     const std::vector<std::string> &_uri_list,
 		     const std::string &_display_name)
 	: source_package(_source_package),
 	  source_version(_source_version),
-          path(_path),
+          uri_list(_uri_list),
 	  display_name(_display_name)
       {
       }
@@ -78,9 +78,15 @@ namespace aptitude
       static boost::shared_ptr<changelog_info>
       create(const std::string &source_package,
 	     const std::string &source_version,
-             const std::string &path,
+             const std::vector<std::string> &uri_list,
 	     const std::string &display_name);
 
+      static boost::shared_ptr<changelog_info>
+      guess(const std::string &source_package,
+	    const std::string &source_version,
+            const std::string &section,
+	    const std::string &display_name);
+
       /** \brief Create a changelog_info structure that describes the
        *  changelog of the given package version.
        *
@@ -94,8 +100,8 @@ namespace aptitude
       const std::string &get_source_package() const { return source_package; }
       /** \brief Retrieve the name of the changelog's source version. */
       const std::string &get_source_version() const { return source_version; }
-      /** \brief Retrieve the path string for changelog url construction. */
-      const std::string &get_path() const { return path; }
+      /** \brief Retrieve the list of URIs to try, in order. */
+      const std::vector<std::string> &get_uri_list() const { return uri_list; }
       /** \brief Retrieve the display name of the changelog's package.
        *
        *  This is the name that should be displayed to the user when,
diff --git a/src/view_changelog.cc b/src/view_changelog.cc
index ae7ed465..0a3d7498 100644
--- a/src/view_changelog.cc
+++ b/src/view_changelog.cc
@@ -385,8 +385,6 @@ public:
 
 void view_changelog(pkgCache::VerIterator ver)
 {
-  bool in_debian=false;
-
   string pkgname = ver.ParentPkg().Name();
 
 
@@ -404,18 +402,6 @@ void view_changelog(pkgCache::VerIterator ver)
     }
 
   // TODO: add a configurable association between origins and changelog URLs.
-  for(pkgCache::VerFileIterator vf=ver.FileList();
-      !vf.end() && !in_debian; ++vf)
-    if(!vf.File().end() && vf.File().Origin()!=NULL &&
-       strcmp(vf.File().Origin(), "Debian")==0)
-      in_debian=true;
-
-  if(!in_debian)
-    {
-      show_message(_("You can only view changelogs of official Debian packages."),
-		   NULL, cw::get_style("Error"));
-      return;
-    }
 
   boost::shared_ptr<changelog_callbacks> callbacks =
     boost::make_shared<changelog_callbacks>(ver.ParentPkg().Name(),