refactor message generation for methods

The format isn't too hard to get right, but it gets funny with multiline
fields (which we don't really have yet) and its just easier to deal with
it once and for all which can be reused for more messages later.

2 files changed, 102 insertions, 90 deletions

diff --git a/apt-pkg/acquire-method.cc b/apt-pkg/acquire-method.cc
index 309b5dcf9..4e034b402 100644
--- a/apt-pkg/acquire-method.cc
+++ b/apt-pkg/acquire-method.cc
@@ -27,7 +27,10 @@
 #include <apt-pkg/sha2.h>
 #include <apt-pkg/strutl.h>
 
+#include <algorithm>
 #include <iostream>
+#include <iterator>
+#include <sstream>
 #include <string>
 #include <vector>
 #include <stdarg.h>
@@ -39,33 +42,41 @@
 
 using namespace std;
 
+// poor mans unordered_map::try_emplace for C++11 as it is a C++17 feature /*{{{*/
+template <typename Arg>
+static void try_emplace(std::unordered_map<std::string, std::string> &fields, std::string &&name, Arg &&value)
+{
+   if (fields.find(name) == fields.end())
+      fields.emplace(std::move(name), std::forward<Arg>(value));
+}
+									/*}}}*/
+
 // AcqMethod::pkgAcqMethod - Constructor				/*{{{*/
 // ---------------------------------------------------------------------
 /* This constructs the initialization text */
 pkgAcqMethod::pkgAcqMethod(const char *Ver,unsigned long Flags)
 {
-   std::cout << "100 Capabilities\n"
-	     << "Version: " << Ver << "\n";
-
+   std::unordered_map<std::string, std::string> fields;
+   try_emplace(fields, "Version", Ver);
    if ((Flags & SingleInstance) == SingleInstance)
-      std::cout << "Single-Instance: true\n";
+      try_emplace(fields, "Single-Instance", "true");
 
    if ((Flags & Pipeline) == Pipeline)
-      std::cout << "Pipeline: true\n";
+      try_emplace(fields, "Pipeline", "true");
 
    if ((Flags & SendConfig) == SendConfig)
-      std::cout << "Send-Config: true\n";
+      try_emplace(fields, "Send-Config", "true");
 
    if ((Flags & LocalOnly) == LocalOnly)
-      std::cout <<"Local-Only: true\n";
+      try_emplace(fields, "Local-Only", "true");
 
    if ((Flags & NeedsCleanup) == NeedsCleanup)
-      std::cout << "Needs-Cleanup: true\n";
+      try_emplace(fields, "Needs-Cleanup", "true");
 
    if ((Flags & Removable) == Removable)
-      std::cout << "Removable: true\n";
+      try_emplace(fields, "Removable", "true");
 
-   std::cout << "\n" << std::flush;
+   SendMessage("100 Capabilities", std::move(fields));
 
    SetNonBlock(STDIN_FILENO,true);
 
@@ -73,6 +84,26 @@ pkgAcqMethod::pkgAcqMethod(const char *Ver,unsigned long Flags)
    QueueBack = 0;
 }
 									/*}}}*/
+void pkgAcqMethod::SendMessage(std::string const &header, std::unordered_map<std::string, std::string> &&fields) /*{{{*/
+{
+   std::cout << header << '\n';
+   for (auto const &f : fields)
+   {
+      if (f.second.empty())
+	 continue;
+      std::cout << f.first << ": ";
+      auto const lines = VectorizeString(f.second, '\n');
+      if (likely(lines.empty() == false))
+      {
+	 std::copy(lines.begin(), std::prev(lines.end()), std::ostream_iterator<std::string>(std::cout, "\n "));
+	 std::cout << *lines.rbegin();
+      }
+      std::cout << '\n';
+   }
+   std::cout << '\n'
+	     << std::flush;
+}
+									/*}}}*/
 // AcqMethod::Fail - A fetch has failed					/*{{{*/
 // ---------------------------------------------------------------------
 /* */
@@ -97,40 +128,35 @@ void pkgAcqMethod::Fail(bool Transient)
 }
 									/*}}}*/
 // AcqMethod::Fail - A fetch has failed					/*{{{*/
-// ---------------------------------------------------------------------
-/* */
 void pkgAcqMethod::Fail(string Err,bool Transient)
 {
    // Strip out junk from the error messages
-   for (string::iterator I = Err.begin(); I != Err.end(); ++I)
-   {
-      if (*I == '\r') 
-	 *I = ' ';
-      if (*I == '\n') 
-	 *I = ' ';
-   }
-
-   if (Queue != 0)
-   {
-      std::cout << "400 URI Failure\nURI: " << Queue->Uri << "\n"
-		<< "Message: " << Err;
-      if (IP.empty() == false && _config->FindB("Acquire::Failure::ShowIP", true) == true)
-	 std::cout << " " << IP;
-      std::cout << "\n";
-      Dequeue();
-   }
+   std::transform(Err.begin(), Err.end(), Err.begin(), [](char const c) {
+      if (c == '\r' || c == '\n')
+	 return ' ';
+      return c;
+   });
+   if (IP.empty() == false && _config->FindB("Acquire::Failure::ShowIP", true) == true)
+      Err.append(" ").append(IP);
+
+   std::unordered_map<std::string, std::string> fields;
+   if (Queue != nullptr)
+      try_emplace(fields, "URI", Queue->Uri);
    else
-      std::cout << "400 URI Failure\nURI: <UNKNOWN>\nMessage: " << Err << "\n";
+      try_emplace(fields, "URI", "<UNKNOWN>");
+   try_emplace(fields, "Message", Err);
 
    if(FailReason.empty() == false)
-      std::cout << "FailReason: " << FailReason << "\n";
+      try_emplace(fields, "FailReason", FailReason);
    if (UsedMirror.empty() == false)
-      std::cout << "UsedMirror: " << UsedMirror << "\n";
-   // Set the transient flag
+      try_emplace(fields, "UsedMirror", UsedMirror);
    if (Transient == true)
-      std::cout << "Transient-Failure: true\n";
+      try_emplace(fields, "Transient-Failure", "true");
 
-   std::cout << "\n" << std::flush;
+   SendMessage("400 URI Failure", std::move(fields));
+
+   if (Queue != nullptr)
+      Dequeue();
 }
 									/*}}}*/
 // AcqMethod::DropPrivsOrDie - Drop privileges or die		/*{{{*/
@@ -146,96 +172,79 @@ void pkgAcqMethod::DropPrivsOrDie()
 
 									/*}}}*/
 // AcqMethod::URIStart - Indicate a download is starting		/*{{{*/
-// ---------------------------------------------------------------------
-/* */
 void pkgAcqMethod::URIStart(FetchResult &Res)
 {
    if (Queue == 0)
       abort();
 
-   std::cout << "200 URI Start\n"
-	     << "URI: " << Queue->Uri << "\n";
+   std::unordered_map<std::string, std::string> fields;
+   try_emplace(fields, "URI", Queue->Uri);
    if (Res.Size != 0)
-      std::cout << "Size: " << std::to_string(Res.Size) << "\n";
-
+      try_emplace(fields, "Size", std::to_string(Res.Size));
    if (Res.LastModified != 0)
-      std::cout << "Last-Modified: " << TimeRFC1123(Res.LastModified, true) << "\n";
-
+      try_emplace(fields, "Last-Modified", TimeRFC1123(Res.LastModified, true));
    if (Res.ResumePoint != 0)
-      std::cout << "Resume-Point: " << std::to_string(Res.ResumePoint) << "\n";
-
+      try_emplace(fields, "Resume-Point", std::to_string(Res.ResumePoint));
    if (UsedMirror.empty() == false)
-      std::cout << "UsedMirror: " << UsedMirror << "\n";
+      try_emplace(fields, "UsedMirror", UsedMirror);
 
-   std::cout << "\n" << std::flush;
+   SendMessage("200 URI Start", std::move(fields));
 }
 									/*}}}*/
 // AcqMethod::URIDone - A URI is finished				/*{{{*/
-// ---------------------------------------------------------------------
-/* */
-static void printHashStringList(char const *const Prefix, HashStringList const *const list)
+static void printHashStringList(std::unordered_map<std::string, std::string> &fields, std::string const &Prefix, HashStringList const &list)
 {
-      for (HashStringList::const_iterator hash = list->begin(); hash != list->end(); ++hash)
-      {
-	 // very old compatibility name for MD5Sum
-	 if (hash->HashType() == "MD5Sum")
-	    std::cout << Prefix << "MD5-Hash: " << hash->HashValue() << "\n";
-	 std::cout << hash->HashType() << "-Hash: " << hash->HashValue() << "\n";
-      }
+   for (auto const &hash : list)
+   {
+      // very old compatibility name for MD5Sum
+      if (hash.HashType() == "MD5Sum")
+	 try_emplace(fields, Prefix + "MD5-Hash", hash.HashValue());
+      try_emplace(fields, Prefix + hash.HashType() + "-Hash", hash.HashValue());
+   }
 }
 void pkgAcqMethod::URIDone(FetchResult &Res, FetchResult *Alt)
 {
    if (Queue == 0)
       abort();
 
-   std::cout << "201 URI Done\n"
-	     << "URI: " << Queue->Uri << "\n";
-
+   std::unordered_map<std::string, std::string> fields;
+   try_emplace(fields, "URI", Queue->Uri);
    if (Res.Filename.empty() == false)
-      std::cout << "Filename: " << Res.Filename << "\n";
-
+      try_emplace(fields, "Filename", Res.Filename);
    if (Res.Size != 0)
-      std::cout << "Size: " << std::to_string(Res.Size) << "\n";
-
+      try_emplace(fields, "Size", std::to_string(Res.Size));
    if (Res.LastModified != 0)
-      std::cout << "Last-Modified: " << TimeRFC1123(Res.LastModified, true) << "\n";
-
-   printHashStringList("", &Res.Hashes);
+      try_emplace(fields, "Last-Modified", TimeRFC1123(Res.LastModified, true));
+   printHashStringList(fields, "", Res.Hashes);
 
    if (UsedMirror.empty() == false)
-      std::cout << "UsedMirror: " << UsedMirror << "\n";
+      try_emplace(fields, "UsedMirror", UsedMirror);
    if (Res.GPGVOutput.empty() == false)
    {
-      std::cout << "GPGVOutput:\n";
-      for (vector<string>::const_iterator I = Res.GPGVOutput.begin();
-	   I != Res.GPGVOutput.end(); ++I)
-	 std::cout << " " << *I << "\n";
+      std::ostringstream os;
+      std::copy(Res.GPGVOutput.begin(), Res.GPGVOutput.end() - 1, std::ostream_iterator<std::string>(os, "\n"));
+      os << *Res.GPGVOutput.rbegin();
+      try_emplace(fields, "GPGVOutput", os.str());
    }
-
    if (Res.ResumePoint != 0)
-      std::cout << "Resume-Point: " << std::to_string(Res.ResumePoint) << "\n";
-
+      try_emplace(fields, "Resume-Point", std::to_string(Res.ResumePoint));
    if (Res.IMSHit == true)
-      std::cout << "IMS-Hit: true\n";
+      try_emplace(fields, "IMS-Hit", "true");
 
-   if (Alt != 0)
+   if (Alt != nullptr)
    {
       if (Alt->Filename.empty() == false)
-	 std::cout << "Alt-Filename: " << Alt->Filename << "\n";
-
+	 try_emplace(fields, "Alt-Filename", Alt->Filename);
       if (Alt->Size != 0)
-	 std::cout << "Alt-Size: " << std::to_string(Alt->Size) << "\n";
-
+	 try_emplace(fields, "Alt-Size", std::to_string(Alt->Size));
       if (Alt->LastModified != 0)
-	 std::cout << "Alt-Last-Modified: " << TimeRFC1123(Alt->LastModified, true) << "\n";
-
-      printHashStringList("Alt-", &Alt->Hashes);
-
+	 try_emplace(fields, "Alt-Last-Modified", TimeRFC1123(Alt->LastModified, true));
       if (Alt->IMSHit == true)
-	 std::cout << "Alt-IMS-Hit: true\n";
+	 try_emplace(fields, "Alt-IMS-Hit", "true");
+      printHashStringList(fields, "Alt-", Alt->Hashes);
    }
 
-   std::cout << "\n" << std::flush;
+   SendMessage("201 URI Done", std::move(fields));
    Dequeue();
 }
 									/*}}}*/
@@ -459,9 +468,10 @@ void pkgAcqMethod::Status(const char *Format,...)
  * the worker will enqueue again later on to the right queue */
 void pkgAcqMethod::Redirect(const string &NewURI)
 {
-   std::cout << "103 Redirect\nURI: " << Queue->Uri << "\n"
-	     << "New-URI: " << NewURI << "\n"
-	     << "\n" << std::flush;
+   std::unordered_map<std::string, std::string> fields;
+   try_emplace(fields, "URI", Queue->Uri);
+   try_emplace(fields, "New-URI", NewURI);
+   SendMessage("103 Redirect", std::move(fields));
    Dequeue();
 }
                                                                         /*}}}*/
diff --git a/apt-pkg/acquire-method.h b/apt-pkg/acquire-method.h
index 2de9cf5c2..fa22085b9 100644
--- a/apt-pkg/acquire-method.h
+++ b/apt-pkg/acquire-method.h
@@ -26,6 +26,7 @@
 #include <time.h>
 
 #include <string>
+#include <unordered_map>
 #include <vector>
 
 #ifndef APT_8_CLEANER_HEADERS
@@ -99,6 +100,7 @@ class pkgAcqMethod
    virtual void Fail(std::string Why, bool Transient = false);
    virtual void URIStart(FetchResult &Res);
    virtual void URIDone(FetchResult &Res,FetchResult *Alt = 0);
+   void SendMessage(std::string const &header, std::unordered_map<std::string, std::string> &&fields);
 
    bool MediaFail(std::string Required,std::string Drive);
    virtual void Exit() {};