add default and override handling for Cnf::FindVector

Automatically handle the override of list options via its parent value
which can even be a comma-separated list of values. It also adds an easy
way of providing a default for the list.

3 files changed, 30 insertions, 4 deletions

diff --git a/apt-pkg/contrib/configuration.cc b/apt-pkg/contrib/configuration.cc
index 4ef4663c0..8eddd56d4 100644
--- a/apt-pkg/contrib/configuration.cc
+++ b/apt-pkg/contrib/configuration.cc
@@ -21,6 +21,7 @@
 #include <apt-pkg/error.h>
 #include <apt-pkg/strutl.h>
 #include <apt-pkg/fileutl.h>
+#include <apt-pkg/init.h>
 
 #include <vector>
 #include <fstream>
@@ -246,12 +247,18 @@ string Configuration::FindDir(const char *Name,const char *Default) const
 // Configuration::FindVector - Find a vector of values			/*{{{*/
 // ---------------------------------------------------------------------
 /* Returns a vector of config values under the given item */
-vector<string> Configuration::FindVector(const char *Name) const
+#if (APT_PKG_MAJOR >= 4 && APT_PKG_MINOR < 13)
+vector<string> Configuration::FindVector(const char *Name) const { return FindVector(Name, ""); }
+#endif
+vector<string> Configuration::FindVector(const char *Name, std::string const &Default) const
 {
    vector<string> Vec;
    const Item *Top = Lookup(Name);
    if (Top == NULL)
-      return Vec;
+      return VectorizeString(Default, ',');
+
+   if (Top->Value.empty() == false)
+      return VectorizeString(Top->Value, ',');
 
    Item *I = Top->Child;
    while(I != NULL)
@@ -259,6 +266,9 @@ vector<string> Configuration::FindVector(const char *Name) const
       Vec.push_back(I->Value);
       I = I->Next;
    }
+   if (Vec.empty() == true)
+      return VectorizeString(Default, ',');
+
    return Vec;
 }
 									/*}}}*/
diff --git a/apt-pkg/contrib/configuration.h b/apt-pkg/contrib/configuration.h
index 8e09ea0a6..c256139f4 100644
--- a/apt-pkg/contrib/configuration.h
+++ b/apt-pkg/contrib/configuration.h
@@ -74,8 +74,22 @@ class Configuration
    std::string Find(std::string const &Name, std::string const &Default) const {return Find(Name.c_str(),Default.c_str());};
    std::string FindFile(const char *Name,const char *Default = 0) const;
    std::string FindDir(const char *Name,const char *Default = 0) const;
+   /** return a list of child options
+    *
+    * Options like Acquire::Languages are handled as lists which
+    * can be overridden and have a default. For the later two a comma
+    * separated list of values is supported.
+    *
+    * \param Name of the parent node
+    * \param Default list of values separated by commas */
+   std::vector<std::string> FindVector(const char *Name, std::string const &Default) const;
+   std::vector<std::string> FindVector(std::string const &Name, std::string const &Default) const { return FindVector(Name.c_str(), Default); };
+#if (APT_PKG_MAJOR >= 4 && APT_PKG_MINOR >= 13)
+   std::vector<std::string> FindVector(const char *Name) const { return FindVector(Name, ""); };
+#else
    std::vector<std::string> FindVector(const char *Name) const;
-   std::vector<std::string> FindVector(std::string const &Name) const { return FindVector(Name.c_str()); };
+#endif
+   std::vector<std::string> FindVector(std::string const &Name) const { return FindVector(Name.c_str(), ""); };
    int FindI(const char *Name,int const &Default = 0) const;
    int FindI(std::string const &Name,int const &Default = 0) const {return FindI(Name.c_str(),Default);};
    bool FindB(const char *Name,bool const &Default = false) const;
diff --git a/apt-pkg/contrib/strutl.cc b/apt-pkg/contrib/strutl.cc
index d4f53ea3a..f8bb3890d 100644
--- a/apt-pkg/contrib/strutl.cc
+++ b/apt-pkg/contrib/strutl.cc
@@ -1130,9 +1130,11 @@ bool TokSplitString(char Tok,char *Input,char **List,
    also, but the advantage is that we have an iteratable vector */
 vector<string> VectorizeString(string const &haystack, char const &split)
 {
+   vector<string> exploded;
+   if (haystack.empty() == true)
+      return exploded;
    string::const_iterator start = haystack.begin();
    string::const_iterator end = start;
-   vector<string> exploded;
    do {
       for (; end != haystack.end() && *end != split; ++end);
       exploded.push_back(string(start, end));