1 files changed, 398 insertions, 0 deletions
diff --git a/lib/versioning.cpp b/lib/versioning.cpp
new file mode 100644
index 00000000..a285bb70
--- /dev/null
+++ b/lib/versioning.cpp
@@ -0,0 +1,398 @@
+#include "versioning.h"
+#include <map>
+#include <zen/file_handling.h>
+#include <zen/file_traverser.h>
+#include <zen/string_tools.h>
+
+using namespace zen;
+
+
+namespace
+{
+Zstring getExtension(const Zstring& relativeName) //including "." if extension is existing, returns empty string otherwise
+{
+    auto iterSep = find_last(relativeName.begin(), relativeName.end(), FILE_NAME_SEPARATOR);
+    auto iterName = iterSep != relativeName.end() ? iterSep + 1 : relativeName.begin(); //find beginning of short name
+    auto iterDot = find_last(iterName, relativeName.end(), Zstr('.')); //equal to relativeName.end() if file has no extension!!
+    return Zstring(&*iterDot, relativeName.end() - iterDot);
+};
+}
+
+bool impl::isMatchingVersion(const Zstring& shortname, const Zstring& shortnameVersion) //e.g. ("Sample.txt", "Sample.txt 2012-05-15 131513.txt")
+{
+    auto iter = shortnameVersion.begin();
+    auto last = shortnameVersion.end();
+
+    auto nextDigit = [&]() -> bool
+    {
+        if (iter == last || !isDigit(*iter))
+            return false;
+        ++iter;
+        return true;
+    };
+    auto nextDigits = [&](size_t count) -> bool
+    {
+        while (count-- > 0)
+            if (!nextDigit())
+                return false;
+        return true;
+    };
+    auto nextChar = [&](Zchar c) -> bool
+    {
+        if (iter == last || *iter != c)
+            return false;
+        ++iter;
+        return true;
+    };
+    auto nextStringI = [&](const Zstring& str) -> bool //windows: ignore case!
+    {
+        if (last - iter < static_cast<ptrdiff_t>(str.size()) || !EqualFilename()(str, Zstring(&*iter, str.size())))
+            return false;
+        iter += str.size();
+        return true;
+    };
+
+    return nextStringI(shortname) && //versioned file starts with original name
+           nextChar(Zstr(' ')) && //validate timestamp: e.g. "2012-05-15 131513"; Regex: \d{4}-\d{2}-\d{2} \d{6}
+           nextDigits(4)       && //YYYY
+           nextChar(Zstr('-')) && //
+           nextDigits(2)       && //MM
+           nextChar(Zstr('-')) && //
+           nextDigits(2)       && //DD
+           nextChar(Zstr(' ')) && //
+           nextDigits(6)       && //HHMMSS
+           nextStringI(getExtension(shortname)) &&
+           iter == last;
+}
+
+
+namespace
+{
+template <class Function>
+void moveItemToVersioning(const Zstring& sourceObj, //throw FileError
+                          const Zstring& relativeName,
+                          const Zstring& versioningDirectory,
+                          const Zstring& timestamp,
+                          Function moveObj) //move source -> target; allowed to throw FileError
+{
+    assert(!startsWith(relativeName, FILE_NAME_SEPARATOR));
+    assert(endsWith(sourceObj, relativeName)); //usually, yes, but we might relax this in the future
+
+    //assemble time-stamped version name
+    const Zstring targetObj = appendSeparator(versioningDirectory) + relativeName + Zstr(' ') + timestamp + getExtension(relativeName);
+    assert(impl::isMatchingVersion(afterLast(relativeName, FILE_NAME_SEPARATOR), afterLast(targetObj, FILE_NAME_SEPARATOR))); //paranoid? no!
+
+    try
+    {
+        moveObj(sourceObj, targetObj); //throw FileError
+    }
+    catch (FileError&) //expected to fail if target directory is not yet existing!
+    {
+        if (!somethingExists(sourceObj)) //no source at all is not an error (however a directory as source when a file is expected, *is* an error!)
+            return; //object *not* processed
+
+        //create intermediate directories if missing
+        const Zstring targetDir = beforeLast(targetObj, FILE_NAME_SEPARATOR);
+        if (!dirExists(targetDir)) //->(minor) file system race condition!
+        {
+            makeDirectory(targetDir); //throw FileError
+            moveObj(sourceObj, targetObj); //throw FileError -> this should work now!
+        }
+        else
+            throw;
+    }
+}
+
+
+//move source to target across volumes; prerequisite: all super-directories of target exist
+//if target already contains some files/dirs they are seen as remnants of a previous incomplete move
+void moveFile(const Zstring& sourceFile, const Zstring& targetFile, CallbackCopyFile& callback) //throw FileError
+{
+    //first try to move directly without copying
+    try
+    {
+        renameFile(sourceFile, targetFile); //throw FileError, ErrorDifferentVolume, ErrorTargetExisting
+        return; //great, we get away cheaply!
+    }
+    //if moving failed treat as error (except when it tried to move to a different volume: in this case we will copy the file)
+    catch (const ErrorDifferentVolume&) {}
+    catch (const ErrorTargetExisting&) {}
+
+    //create target
+    if (!fileExists(targetFile)) //check even if ErrorTargetExisting: me may have clashed with another item type of the same name!!!
+    {
+        //file is on a different volume: let's copy it
+        if (symlinkExists(sourceFile))
+            copySymlink(sourceFile, targetFile, false); //throw FileError; don't copy filesystem permissions
+        else
+            copyFile(sourceFile, targetFile, false, true, &callback); //throw FileError - permissions "false", transactional copy "true"
+    }
+
+    //delete source
+    removeFile(sourceFile); //throw FileError; newly copied file is NOT deleted if exception is thrown here!
+}
+
+
+void moveDirSymlink(const Zstring& sourceLink, const Zstring& targetLink) //throw FileError
+{
+    //first try to move directly without copying
+    try
+    {
+        renameFile(sourceLink, targetLink); //throw FileError, ErrorDifferentVolume, ErrorTargetExisting
+        return; //great, we get away cheaply!
+    }
+    //if moving failed treat as error (except when it tried to move to a different volume: in this case we will copy the file)
+    catch (const ErrorDifferentVolume&) {}
+    catch (const ErrorTargetExisting&) {}
+
+    //create target
+    if (!symlinkExists(targetLink)) //check even if ErrorTargetExisting: me may have clashed with another item type of the same name!!!
+    {
+        //link is on a different volume: let's copy it
+        copySymlink(sourceLink, targetLink, false); //throw FileError; don't copy filesystem permissions
+    }
+
+    //delete source
+    removeDirectory(sourceLink); //throw FileError; newly copied link is NOT deleted if exception is thrown here!
+}
+
+
+struct CopyCallbackImpl : public CallbackCopyFile
+{
+    CopyCallbackImpl(CallbackMoveFile& callback) : callback_(callback) {}
+
+private:
+    virtual void deleteTargetFile(const Zstring& targetFile) { assert(!somethingExists(targetFile)); }
+    virtual void updateCopyStatus(Int64 bytesDelta) { callback_.updateStatus(bytesDelta); }
+
+    CallbackMoveFile& callback_;
+};
+
+
+class TraverseFilesOneLevel : public TraverseCallback
+{
+public:
+    TraverseFilesOneLevel(std::vector<Zstring>& files, std::vector<Zstring>& dirs) : files_(files), dirs_(dirs) {}
+
+private:
+    virtual void onFile(const Zchar* shortName, const Zstring& fullName, const FileInfo& details)
+    {
+        files_.push_back(shortName);
+    }
+
+    virtual HandleLink onSymlink(const Zchar* shortName, const Zstring& fullName, const SymlinkInfo& details)
+    {
+        if (details.dirLink)
+            dirs_.push_back(shortName);
+        else
+            files_.push_back(shortName);
+        return LINK_SKIP;
+    }
+
+    virtual std::shared_ptr<TraverseCallback> onDir(const Zchar* shortName, const Zstring& fullName)
+    {
+        dirs_.push_back(shortName);
+        return nullptr; //DON'T traverse into subdirs; moveDirectory works recursively!
+    }
+
+    virtual HandleError onError(const std::wstring& msg) { throw FileError(msg); }
+
+    std::vector<Zstring>& files_;
+    std::vector<Zstring>& dirs_;
+};
+
+
+struct RemoveCallbackImpl : public CallbackRemoveDir
+{
+    RemoveCallbackImpl(CallbackMoveFile& callback) : callback_(callback) {}
+
+private:
+    virtual void notifyFileDeletion(const Zstring& filename) { callback_.updateStatus(0); }
+    virtual void notifyDirDeletion (const Zstring& dirname ) { callback_.updateStatus(0); }
+
+    CallbackMoveFile& callback_;
+};
+}
+
+
+void FileVersioner::revisionFile(const Zstring& sourceFile, const Zstring& relativeName, CallbackMoveFile& callback) //throw FileError
+{
+    moveItemToVersioning(sourceFile, //throw FileError
+                         relativeName,
+                         versioningDirectory_,
+                         timeStamp_,
+                         [&](const Zstring& source, const Zstring& target)
+    {
+        callback.onBeforeFileMove(source, target);
+
+        CopyCallbackImpl copyCallback(callback);
+        moveFile(source, target, copyCallback); //throw FileError
+        callback.objectProcessed();
+    });
+
+    fileRelnames.push_back(relativeName);
+}
+
+
+void FileVersioner::revisionDir(const Zstring& sourceDir, const Zstring& relativeName, CallbackMoveFile& callback) //throw FileError
+{
+    //note: we cannot support "throw exception if target already exists": If we did, we would have to do a full cleanup
+    //removing all newly created directories in case of an exception so that subsequent tries would not fail with "target already existing".
+    //However an exception may also happen during final deletion of source folder, in which case cleanup effectively leads to data loss!
+
+    //create target
+    if (symlinkExists(sourceDir)) //on Linux there is just one type of symlinks, and since we do revision file symlinks, we should revision dir symlinks as well!
+    {
+        moveItemToVersioning(sourceDir, //throw FileError
+                             relativeName,
+                             versioningDirectory_,
+                             timeStamp_,
+                             [&](const Zstring& source, const Zstring& target)
+        {
+            callback.onBeforeDirMove(source, target);
+            moveDirSymlink(source, target); //throw FileError
+            callback.objectProcessed();
+        });
+
+        fileRelnames.push_back(relativeName);
+    }
+    else
+    {
+        assert(!startsWith(relativeName, FILE_NAME_SEPARATOR));
+        assert(endsWith(sourceDir, relativeName));
+        const Zstring targetDir = appendSeparator(versioningDirectory_) + relativeName;
+
+        callback.onBeforeDirMove(sourceDir, targetDir);
+
+        //makeDirectory(targetDir); //FileError -> create only when needed in moveFileToVersioning(); avoids empty directories
+
+        //traverse source directory one level
+        std::vector<Zstring> fileList; //list of *short* names
+        std::vector<Zstring> dirList;  //
+        try
+        {
+            TraverseFilesOneLevel tol(fileList, dirList); //throw FileError
+            traverseFolder(sourceDir, tol);                   //
+        }
+        catch (FileError&)
+        {
+            if (!somethingExists(sourceDir)) //no source at all is not an error (however a file as source when a directory is expected, *is* an error!)
+                return; //object *not* processed
+            throw;
+        }
+
+        const Zstring sourceDirPf = appendSeparator(sourceDir);
+        const Zstring relnamePf   = appendSeparator(relativeName);
+
+        //move files
+        std::for_each(fileList.begin(), fileList.end(),
+                      [&](const Zstring& shortname)
+        {
+            revisionFile(sourceDirPf + shortname, //throw FileError
+                         relnamePf + shortname,
+                         callback);
+        });
+
+        //move directories
+        std::for_each(dirList.begin(), dirList.end(),
+                      [&](const Zstring& shortname)
+        {
+            revisionDir(sourceDirPf + shortname, //throw FileError
+                        relnamePf + shortname,
+                        callback);
+        });
+
+        //delete source
+        RemoveCallbackImpl removeCallback(callback);
+        removeDirectory(sourceDir, &removeCallback); //throw FileError
+
+        callback.objectProcessed();
+    }
+}
+
+
+namespace
+{
+class TraverseVersionsOneLevel : public TraverseCallback
+{
+public:
+    TraverseVersionsOneLevel(std::vector<Zstring>& files, std::function<void()> updateUI) : files_(files), updateUI_(updateUI) {}
+
+private:
+    virtual void onFile(const Zchar* shortName, const Zstring& fullName, const FileInfo& details) { files_.push_back(shortName); updateUI_(); }
+    virtual HandleLink onSymlink(const Zchar* shortName, const Zstring& fullName, const SymlinkInfo& details) { files_.push_back(shortName); updateUI_(); return LINK_SKIP; }
+    virtual std::shared_ptr<TraverseCallback> onDir(const Zchar* shortName, const Zstring& fullName) { updateUI_(); return nullptr; } //DON'T traverse into subdirs
+    virtual HandleError onError(const std::wstring& msg) { throw FileError(msg); }
+
+    std::vector<Zstring>& files_;
+    std::function<void()> updateUI_;
+};
+}
+
+
+void FileVersioner::limitVersions(std::function<void()> updateUI) //throw FileError
+{
+    if (versionCountLimit_ < 0) //no limit!
+        return;
+
+    //buffer map "directory |-> list of immediate child file and symlink short names"
+    std::map<Zstring, std::vector<Zstring>, LessFilename> dirBuffer;
+
+    auto getVersionsBuffered = [&](const Zstring& dirname) -> const std::vector<Zstring>&
+    {
+        auto iter = dirBuffer.find(dirname);
+        if (iter != dirBuffer.end())
+            return iter->second;
+
+        std::vector<Zstring> fileShortNames;
+        TraverseVersionsOneLevel tol(fileShortNames, updateUI); //throw FileError
+        traverseFolder(dirname, tol);
+
+        auto& newEntry = dirBuffer[dirname]; //transactional behavior!!!
+        newEntry.swap(fileShortNames);       //-> until C++11 emplace is available
+
+        return newEntry;
+    };
+
+    std::for_each(fileRelnames.begin(), fileRelnames.end(),
+                  [&](const Zstring& relativeName) //e.g. "subdir\Sample.txt"
+    {
+        const Zstring fullname = appendSeparator(versioningDirectory_) + relativeName; //e.g. "D:\Revisions\subdir\Sample.txt"
+        const Zstring parentDir = beforeLast(fullname, FILE_NAME_SEPARATOR);    //e.g. "D:\Revisions\subdir"
+        const Zstring shortname = afterLast(relativeName, FILE_NAME_SEPARATOR); //e.g. "Sample.txt"; returns the whole string if seperator not found
+
+        const std::vector<Zstring>& allVersions = getVersionsBuffered(parentDir);
+
+        //filter out only those versions that match the given relative name
+        std::vector<Zstring> matches; //e.g. "Sample.txt 2012-05-15 131513.txt"
+
+        std::copy_if(allVersions.begin(), allVersions.end(), std::back_inserter(matches),
+        [&](const Zstring& shortnameVer) { return impl::isMatchingVersion(shortname, shortnameVer); });
+
+        //take advantage of version naming convention to find oldest versions
+        if (matches.size() <= static_cast<size_t>(versionCountLimit_))
+            return;
+        std::nth_element(matches.begin(), matches.end() - versionCountLimit_, matches.end(), LessFilename()); //windows: ignore case!
+
+        //delete obsolete versions
+        std::for_each(matches.begin(), matches.end() - versionCountLimit_,
+                      [&](const Zstring& shortnameVer)
+        {
+            updateUI();
+            const Zstring fullnameVer = parentDir + FILE_NAME_SEPARATOR + shortnameVer;
+            try
+            {
+                removeFile(fullnameVer); //throw FileError
+            }
+            catch (FileError&)
+            {
+#ifdef FFS_WIN //if it's a directory symlink:
+                if (symlinkExists(fullnameVer) && dirExists(fullnameVer))
+                    removeDirectory(fullnameVer); //throw FileError
+                else
+#endif
+                    throw;
+            }
+        });
+    });
+}