"backport" the APT::Configuration class to apt-sid

We can use it to simplify the internal code to operate with
Acquire::CompressionTypes group. This also made it possible
to set this setting with the -o flag.

5 files changed, 151 insertions, 62 deletions

diff --git a/apt-pkg/acquire-item.cc b/apt-pkg/acquire-item.cc
index ffbe66d7d..94341c81a 100644
--- a/apt-pkg/acquire-item.cc
+++ b/apt-pkg/acquire-item.cc
@@ -15,6 +15,7 @@
 // Include Files							/*{{{*/
 #include <apt-pkg/acquire-item.h>
 #include <apt-pkg/configuration.h>
+#include <apt-pkg/aptconfiguration.h>
 #include <apt-pkg/sourcelist.h>
 #include <apt-pkg/vendorlist.h>
 #include <apt-pkg/error.h>
@@ -551,21 +552,11 @@ pkgAcqIndex::pkgAcqIndex(pkgAcquire *Owner,
    if(comprExt.empty()) 
    {
       // autoselect the compression method
-      Configuration::Item const *Opts = _config->Tree("Acquire::CompressionTypes");
-      if (Opts != 0)
-	 Opts = Opts->Child;
-
-      const char dirBin[] = "Dir::Bin::";
-      for (; Opts != 0; Opts = Opts->Next)
-      {
-	 if (Opts->Tag.empty() == true || Opts->Value.empty() == true)
-	    continue;
-	 const string bin = _config->FindFile(string(dirBin).append(Opts->Value).c_str(),"");
-	 if (bin != "" && !FileExists(bin))
-	    continue;
-	 comprExt = '.' + Opts->Tag;
-	 break;
-      }
+      std::vector<std::string> types = APT::Configuration::getCompressionTypes();
+      if (types.empty() == true)
+	 comprExt = "plain";
+      else
+	 comprExt = "." + types[0];
    }
    CompressionExtension = ((comprExt == "plain" || comprExt == ".") ? "" : comprExt);
 
@@ -595,36 +586,31 @@ string pkgAcqIndex::Custom600Headers()
 									/*}}}*/
 void pkgAcqIndex::Failed(string Message,pkgAcquire::MethodConfig *Cnf)	/*{{{*/
 {
-   Configuration::Item const *Opts = _config->Tree("Acquire::CompressionTypes");
-   if (Opts != 0)
-      Opts = Opts->Child;
+   std::vector<std::string> types = APT::Configuration::getCompressionTypes();
 
-   const char dirBin[] = "Dir::Bin::";
-   for (; Opts != 0; Opts = Opts->Next)
+   for (std::vector<std::string>::const_iterator t = types.begin();
+	t != types.end(); t++)
    {
-      if (Opts->Tag.empty() == true || Opts->Value.empty() == true)
+      // jump over all already tried compression types
+      const unsigned int nameLen = Desc.URI.size() - (*t).size();
+      if(Desc.URI.substr(nameLen) != *t)
 	 continue;
 
-      // jump over all already checked compression types
-      const unsigned int nameLen = Desc.URI.size() - Opts->Tag.size();
-      if(Desc.URI.substr(nameLen) != Opts->Tag || Opts->Next == 0)
-	 continue;
-
-      // check if we need an external binary for this compression type
-      const string bin = _config->FindFile(string(dirBin).append(Opts->Next->Value).c_str(),"");
-      if (bin != "" && !FileExists(bin))
-	 continue;
+      // we want to try it with the next extension
+      t++;
 
-      // retry with the next extension
-      Desc.URI = Desc.URI.substr(0, nameLen) + Opts->Next->Tag;
+      if (t != types.end())
+      {
+	 Desc.URI = Desc.URI.substr(0, nameLen) + *t;
 
-      new pkgAcqIndex(Owner, RealURI, Desc.Description, Desc.ShortDesc,
-			ExpectedHash, string(".").append(Opts->Next->Tag));
+	 new pkgAcqIndex(Owner, RealURI, Desc.Description, Desc.ShortDesc,
+			 ExpectedHash, string(".").append(*t));
 
-      Status = StatDone;
-      Complete = false;
-      Dequeue();
-      return;
+	 Status = StatDone;
+	 Complete = false;
+	 Dequeue();
+	 return;
+      }
    }
 
    // on decompression failure, remove bad versions in partial/
diff --git a/apt-pkg/aptconfiguration.cc b/apt-pkg/aptconfiguration.cc
new file mode 100644
index 000000000..1a8e8262f
--- /dev/null
+++ b/apt-pkg/aptconfiguration.cc
@@ -0,0 +1,78 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Provide access methods to various configuration settings,
+   setup defaults and returns validate settings.
+
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/configuration.h>
+
+#include <vector>
+#include <string>
+									/*}}}*/
+namespace APT {
+// getCompressionTypes - Return Vector of usbale compressiontypes	/*{{{*/
+// ---------------------------------------------------------------------
+/* return a vector of compression types in the prefered order. */
+std::vector<std::string>
+const Configuration::getCompressionTypes(bool const &Cached) {
+	static std::vector<std::string> types;
+	if (types.empty() == false) {
+		if (Cached == true)
+			return types;
+		else
+			types.clear();
+	}
+
+	// Set default application paths to check for optional compression types
+	_config->CndSet("Dir::Bin::lzma", "/usr/bin/lzma");
+	_config->CndSet("Dir::Bin::bzip2", "/bin/bzip2");
+
+	::Configuration::Item const *Opts = _config->Tree("Acquire::CompressionTypes");
+	if (Opts != 0)
+		Opts = Opts->Child;
+
+	// at first, move over the options to setup at least the default options
+	bool foundLzma=false, foundBzip2=false, foundGzip=false;
+	for (; Opts != 0; Opts = Opts->Next) {
+		if (Opts->Value == "lzma")
+			foundLzma = true;
+		else if (Opts->Value == "bz2")
+			foundBzip2 = true;
+		else if (Opts->Value == "gz")
+			foundGzip = true;
+	}
+
+	// setup the defaults now
+	if (!foundBzip2)
+		_config->Set("Acquire::CompressionTypes::bz2","bzip2");
+	if (!foundLzma)
+		_config->Set("Acquire::CompressionTypes::lzma","lzma");
+	if (!foundGzip)
+		_config->Set("Acquire::CompressionTypes::gz","gzip");
+
+	// move again over the option tree to finially calculate our result
+	::Configuration::Item const *Types = _config->Tree("Acquire::CompressionTypes");
+	if (Types != 0)
+		Types = Types->Child;
+
+	for (; Types != 0; Types = Types->Next) {
+		string const appsetting = string("Dir::Bin::").append(Types->Value);
+		// ignore compression types we have no app ready to use
+		if (appsetting.empty() == false && _config->Exists(appsetting) == true) {
+			std::string const app = _config->FindFile(appsetting.c_str(), "");
+			if (app.empty() == false && FileExists(app) == false)
+				continue;
+		}
+		types.push_back(Types->Tag);
+	}
+
+	return types;
+}
+									/*}}}*/
+}
diff --git a/apt-pkg/aptconfiguration.h b/apt-pkg/aptconfiguration.h
new file mode 100644
index 000000000..6a123adce
--- /dev/null
+++ b/apt-pkg/aptconfiguration.h
@@ -0,0 +1,46 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/** \class APT::Configuration
+ *  \brief Provide access methods to various configuration settings
+ *
+ *  This class and their methods providing a layer around the usual access
+ *  methods with _config to ensure that settings are correct and to be able
+ *  to set defaults without the need to recheck it in every method again.
+ */
+									/*}}}*/
+#ifndef APT_CONFIGURATION_H
+#define APT_CONFIGURATION_H
+// Include Files							/*{{{*/
+#include <string>
+#include <vector>
+									/*}}}*/
+namespace APT {
+class Configuration {							/*{{{*/
+public:									/*{{{*/
+	/** \brief Returns a vector of usable Compression Types
+	 *
+	 *  Files can be compressed in various ways to decrease the size of the
+	 *  download. Therefore the Acquiremethods support a few compression types
+	 *  and some archives provide also a few different types. This option
+	 *  group exists to give the user the choice to prefer one type over the
+	 *  other (some compression types are very resource intensive - great if you
+	 *  have a limited download, bad if you have a really lowpowered hardware.)
+	 *
+	 *  This method ensures that the defaults are set and checks at runtime
+	 *  if the type can be used. E.g. the current default is to prefer bzip2
+	 *  over lzma and gz - if the bzip2 binary is not available it has not much
+	 *  sense in downloading the bz2 file, therefore we will not return bz2 as
+	 *  a usable compression type. The availability is checked with the settings
+	 *  in the Dir::Bin group.
+	 *
+	 *  \param Cached saves the result so we need to calculated it only once
+	 *                this parameter should ony be used for testing purposes.
+	 *
+	 *  \return a vector of (all) Language Codes in the prefered usage order
+	 */
+	std::vector<std::string> static const getCompressionTypes(bool const &Cached = true);
+									/*}}}*/
+};
+									/*}}}*/
+}
+#endif
diff --git a/apt-pkg/init.cc b/apt-pkg/init.cc
index 46017bf0c..15efb1a3d 100644
--- a/apt-pkg/init.cc
+++ b/apt-pkg/init.cc
@@ -104,28 +104,6 @@ bool pkgInitConfig(Configuration &Cnf)
    if (Res == false)
       return false;
 
-   // we load all config files, now check the configs and setup post-defaults:
-   // * check for CompressionTypes setup
-   {
-      Configuration::Item const *Opts = _config->Tree("Acquire::CompressionTypes");
-      if (Opts != 0)
-	 Opts = Opts->Child;
-      bool foundLzma=false, foundBzip2=false, foundGzip=false;
-      for (; Opts != 0; Opts = Opts->Next)
-      {
-	 if (Opts->Value == "lzma") foundLzma = true;
-	 else if (Opts->Value == "bz2") foundBzip2 = true;
-	 else if (Opts->Value == "gz") foundGzip = true;
-      }
-      if (!foundBzip2) Cnf.Set("Acquire::CompressionTypes::bz2","bzip2");
-      if (!foundLzma) Cnf.Set("Acquire::CompressionTypes::lzma","lzma");
-      if (!foundGzip) Cnf.Set("Acquire::CompressionTypes::gz","gzip");
-      Cnf.CndSet("Dir::Bin::lzma", "/usr/bin/lzma");
-      Cnf.CndSet("Dir::Bin::bzip2", "/bin/bzip2");
-   }
-
-
-
    if (Cnf.FindB("Debug::pkgInitConfig",false) == true)
       Cnf.Dump();
    
diff --git a/apt-pkg/makefile b/apt-pkg/makefile
index 92ef58967..679d97e70 100644
--- a/apt-pkg/makefile
+++ b/apt-pkg/makefile
@@ -34,14 +34,15 @@ SOURCE+= pkgcache.cc version.cc depcache.cc \
 	 acquire-worker.cc acquire-method.cc init.cc clean.cc \
 	 srcrecords.cc cachefile.cc versionmatch.cc policy.cc \
 	 pkgsystem.cc indexfile.cc pkgcachegen.cc acquire-item.cc \
-	 indexrecords.cc vendor.cc vendorlist.cc cdrom.cc indexcopy.cc
+	 indexrecords.cc vendor.cc vendorlist.cc cdrom.cc indexcopy.cc \
+	 aptconfiguration.cc
 HEADERS+= algorithms.h depcache.h pkgcachegen.h cacheiterators.h \
 	  orderlist.h sourcelist.h packagemanager.h tagfile.h \
 	  init.h pkgcache.h version.h progress.h pkgrecords.h \
 	  acquire.h acquire-worker.h acquire-item.h acquire-method.h \
 	  clean.h srcrecords.h cachefile.h versionmatch.h policy.h \
 	  pkgsystem.h indexfile.h metaindex.h indexrecords.h vendor.h \
-          vendorlist.h cdrom.h indexcopy.h
+          vendorlist.h cdrom.h indexcopy.h aptconfiguration.h
 
 # Source code for the debian specific components
 # In theory the deb headers do not need to be exported..