R/getTag.R

In envDocument: Document the R Working Environment

# getTag
# 
# Return git tag information if relavant
# Requires that repostiory have tags and that sha for last tag
# and last commit match.  
# 
getTag <- function(repo) {
  tagString <- NULL
  
  # get tags
  tagList <- git2r::tags(repo)
  
  # Abort if no tags in repo
  if(length(tagList) ==  0) {
    return(NULL)
  }
  
  tagInfo <- lapply(tagList, parseS3Tag)

  tagInfo <- do.call("rbind", tagInfo)
  
  # get sha for last commit
  lastCommit <- git2r::commits(repo, n = 1)[[1]]

  last <- as.data.frame(lastCommit) # will methods::as work on S3?


  # do any tag targets match last commit? if not, return null
  if( !any(last$sha == tagInfo$target) ) { return(NULL) }
  
  # return info for tag that matches target
  tagTarget <- tagInfo[ (last$sha == tagInfo$target), ]
  
  tagString <- paste( "[", substring(tagTarget$target, 1,6), "] ", tagTarget$name, 
                      sep = "" )
  return(tagString)
  
}

# parseS3Tags
#
# function to parse individual tags using S3 structure

parseS3Tag <- function(thisTag) {
  # if the repo has any lightweight tags, tagger is in author.
  # otherwise it's in tagger
  
  if("tagger" %in% names(thisTag)) {
    tagger <- thisTag$tagger
    tagName <- thisTag$name
    tagTarget <- thisTag$target
  } else if ("author" %in% names(thisTag)) {
    tagger <- thisTag$author
    tagName <- NA
    tagTarget <- thisTag$sha
  } else {
    return(NULL)
  }
  
  thisTagTime <- tagger$when$time
  
  thisTagInfo <- data.frame( #sha = thisTag$sha,
                             target= tagTarget,
                             when = thisTagTime,
                             name = tagName,
                             message = thisTag$message,
                             person = tagger$name,
                             email = tagger$email
                             )
  
  return(thisTagInfo)
  
}