How to detect a file rename using Rugged? - rugged

I'm a novice Rugged user, and I'm attempting to detect file renames in the commit history. I'm diffing each commit against its first parent, as follows:
repo = Rugged::Repository.discover("foo")
walker = Rugged::Walker.new(repo)
walker.sorting(Rugged::SORT_TOPO)
walker.push("master")
walker.each.take(200).each do |commit|
puts commit.oid
puts commit.message
diffs = nil
# Handle Root commit
if commit.parents.count > 0 then
diffs = commit.parents[0].diff(commit)
else
diffs = commit.diff(nil)
end
(files,additions,deletions) = diffs.stat
puts "Files changed: #{files}, Additions: #{additions}, Deletions: #{deletions}"
paths = [];
diffs.each_delta do |delta|
old_file_path = delta.old_file[:path]
new_file_path = delta.new_file[:path]
puts delta.status
puts delta.renamed?
puts delta.similarity
paths += [delta]
end
puts "Paths:"
puts paths
puts "===================================="
end
walker.reset
However, when I do have a rename, the program will output an addition and a removal (A and D status). This matches the output of git log --name-status.
On the other hand, I found out that using git log --name-status --format='%H' --follow -- b.txt correctly shows the rename as R100.
The repo history and the outputs of git can be seen in the following gist: https://gist.github.com/ifigueroap/60716bbf4aa2f205b9c9
My question is how to use the Diff, or Delta objects of Rugged to detect such a file rename...
Thanks

Before accessing diffs.stat, you should call diffs.find_similar! with :renames => true. That'll modify the diffs object to do include rename information. This is not done by default, as the underlying operation is quite complex and not needed in most cases.
Check the documentation for find_similar! here: https://github.com/libgit2/rugged/blob/e96d26174b2bf763e9dd5dd2370e79f5e29077c9/ext/rugged/rugged_diff.c#L310-L366 for more options.

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Ruby Simple Read/Write File (Copy File)

I am practicing Ruby, and I am trying to copy contents from file "from" to file "to". can you tell me where I did it wrong?
thanks !
from = "1.txt"
to = "2.txt"
data = open(from).read
out = open(to, 'w')
out.write(data)
out.close
data.close
Maybe I am missing the point, but I think writing it like so is more 'ruby'
from = "1.txt"
to = "2.txt"
contents = File.open(from, 'r').read
File.open(to, 'w').write(contents)
Personally, however, I like to use the Operating systems terminal to do File operations like so. Here is an example on linux.
from = "1.txt"
to = "2.txt"
system("cp #{from} #{to}")
And for Windows I believe you would use..
from = "1.txt"
to = "2.txt"
system("copy #{from} #{to}")
Finally, if you were needing the output of the command for some sort of logging or other reason, I would use backticks.
#A nice one liner
`cp 1.txt 2.txt`
Here is the system and backtick methods documentation.
http://ruby-doc.org/core-1.9.3/Kernel.html
You can't perform data.close — data.class would show you that you have a String, and .close is not a valid String method. By opening from the way you chose to, you lost the File reference after using it with your read. One way to fix that would be:
from = "1.txt"
to = "2.txt"
infile = open(from) # Retain the File reference
data = infile.read # Use it to do the read
out = open(to, 'w')
out.write(data)
out.close
infile.close # And finally, close it

get all commit of a file/path with rugged

I would like to get the list of all the commits for a file/path but I don't know how to do it.
For example I want all the commit of the file "test", to get oid of each commit and thanks to this oid, I will get the blob of all revision for this file.
Is it possible ?
Thanks !
We can get all commits by this way :
tab = []
walker = Rugged::Walker.new(repo)
walker.sorting(Rugged::SORT_DATE)
walker.push(repo.head.target)
walker.each do |commit|
if commit.diff(paths: ["path_of_file"]).size > 0
tab.push(commit)
end
end

How to interactively run mount command from a (Ruby) script?

I am trying to write a Ruby script that runs the mount command interactively behind the scenes. The problem is, if I redirect input and output of the mount command to pipes, it doesn't work. Somehow, mount seems to realise that it's not talking directly to stdin/stdout and falls over. Either that, or it's a more wide-ranging problem that would affect all interactive commands; I don't know.
I want to be able to parse the output of mount, line by line, and shove answers into its input pipe when it asks questions. This shouldn't be an unreasonable expectation. Can someone help, please?
Examples:
def read_until(pipe, stop_at, timeoutsec = 10, verbose = false)
lines = []; line = ""
while result = IO.select([pipe], nil, nil, timeoutsec)
next if result.empty?
begin
c = pipe.read(1) rescue c = nil
end
break if c.nil?
line << c
break if line =~ stop_at
# Start a new line?
if line[-1] == ?\n
puts line if verbose
lines << line.strip
line = ""
end
end
return lines, line.match(stop_at)
end
cmd = "mount.ecryptfs -f /tmp/1 /tmp/2"
status = Open3::popen2e(cmd) { |i,o,t|
o.fcntl(3, 4) # Set non-blocking (this doesn't make any difference)
i.fcntl(3, 4) # Set non-blocking (this doesn't make any difference)
puts read_until(o, /some pattern/, 1, true) # Outputs [[], nil]
}
I've also tried spawn:
a, b = IO.pipe
c, d = IO.pipe
pid = spawn(cmd, :in=>a, :out=>d)
puts read_until(c, /some pattern/, 1, true) # Outputs [[], nil]
I've tried subprocess, pty and a host of other solutions - basically, if it's on Google, I've tried it. It seems that mount just knows if I'm not passing it a real shell, and deliberately blocks. See:
pid = spawn(cmd, :in=>STDIN, :out=>STDOUT) # Works
pid = spawn(cmd, :in=>somepipe, :out=>STDOUT) # Blocks after first line of output, for no reason whatsoever. It's not expecting any input at this point.
I even tried spawning a real shell (e.g. bash) and sending the mount command to it via an input pipe. Same problem.
Please ignore any obvious errors in the above: I have tried several solutions tonight, so the actual code has been rewritten many times. I wrote the above from memory.
What I want is the following:
Run mount command with arguments, getting pipes for its input and output streams
Wait for first specific question on output pipe
Answer specific question by writing to input pipe
Wait for second specific question on output pipe
...etc...
And so on.
You may find Kernel#system useful. It opens a subshell, so if you are ok w/ the user just interacting with mount directly this will make everything much easier.

Access git log data using ruby rugged gem?

For a given file in a git repo, I'd like to look up the SHA of the last commit in which the file was modified, along with the timestamp.
At the command line, this data is visible with git log for a particular file path, e.g.
git log -n 1 path/to/file
Using the "git" gem for ruby I can also do this:
require 'git'
g = Git.open("/path/to/repo")
modified = g.log(1).object(relative/path/to/file).first.date
sha = g.log(1).object(relative/path/to/file).first.sha
Which is great, but is running too slowly for me when looping through lots of paths. As Rugged uses C libraries instead, I was hoping it would be faster but cannot see how to construct the right query in the rugged syntax. Any suggestions?
This should work:
repo = Rugged::Repository.new("/path/to/repo")
walker = Rugged::Walker.new(repo)
walker.sorting(Rugged::SORT_DATE)
walker.push(repo.head.target)
commit = walker.find do |commit|
commit.parents.size == 1 && commit.diff(paths: ["relative/path/to/file"]).size > 0
end
sha = commit.oid
Taken and adapted from https://github.com/libgit2/pygit2/issues/200#issuecomment-15899713
As an aside: Just because rugged is written in C does not mean that costly operations suddenly become cheap and quick. Obviously, you save a lot of string parsing and stuff like that, but this is not always the bottleneck.
As you're not interested in the actual textual diff here, the libgit2 GIT_DIFF_FORCE_BINARY might be something that could also help in increasing the performance of this lookup - unfortunately this is not yet available in Rugged (but will be, soon).
Testing this with the Rugged repo itself, it works correctly:
repo = Rugged::Repository.new(".")
walker = Rugged::Walker.new(repo)
walker.sorting(Rugged::SORT_DATE)
walker.push(repo.head.target)
commit = walker.find do |commit|
commit.parents.size == 1 && commit.diff(paths: ["Gemfile"]).size > 0
end
sha = commit.oid # => "8f5c763377f5bf0fb88d196b7c45a7d715264ad4"
walker = Rugged::Walker.new(repo)
walker.sorting(Rugged::SORT_DATE)
walker.push(repo.head.target)
commit = walker.find do |commit|
commit.parents.size == 1 && commit.diff(paths: [".travis.yml"]).size > 0
end
sha = commit.oid # => "4e18e05944daa2ba8d63a2c6b149900e3b93a88f"

Find and delete oldest AVI file recursively

I've been trying to write a Ruby script to find and delete the oldest AVI file in a folder. I found a script in Python that is very close, and I got a good start on the Ruby solution myself with:
require 'fileutils'
stat = Sys::Filesystem.stat("/")
mb_available = stat.block_size * stat.blocks_available / 1024 / 1024
#if there is less than 130MB free
if mb_available < 130000
require 'find'
movie_file_paths = []
#grab all the files in the folder
Find.find('/Users/jody/Movies') do |path|
movie_file_paths << path if /.*\.avi/.match(path) != nil
end
end
But, I'm having a tough time with the rest. Any help would be appreciated!
EDIT:
This was the solution:
movie_file_paths = []
Dir.glob("/Users/jody/Movies/**/*.avi").each { |file| movie_file_paths << file if File.file? file }
movie_file_paths.sort_by {|f| File.mtime(f)}
deleteme = movie_file_paths.first
I see you've already selected an answer but it can be a one-liner:
File.delete(Dir.glob("/Users/jody/Movies/**/*.avi").sort_by{|f| File.mtime(f)}.first)
Update: I came across this a few years later and thought to myself, "I can make that shorter!"
File.delete(Dir["/Users/jody/Movies/**/*.avi"]).min_by{|f| File.mtime(f)})
File has the methods you want, specifically ctime for "last changed" times (creation times on NTFS), mtime if you want "last modified" times, or atime for "last accessed" times. Combining this with Dir::glob, you can easily get a list of files sorted by datetime:
videos = Dir['/Users/jody/Movies/*.avi'].sort_by(&:ctime)
Deleting the last one is very simple:
File.delete videos.last
Use File.mtime(filename) to get the last modified time of the file.
movie_file_path.sort_by {|f| File.mtime(f)} will return a sorted array by mtime. You can then delete the file using File.delete(filename).
Edit: Last accessed time atime might be a better option than mtime.

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