Add ref_extractor helper module for upcoming controllers

Robert Speicher
1 parent b389247c
Showing 2 changed files with 103 additions and 0 deletions Show diff stats
lib/ref_extractor.rb
spec/lib/ref_extractor_spec.rb
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+# Module providing an extract_ref method for controllers working with Git
+# tree-ish + path params
+#
+# Given a string containing both a Git ref - such as a branch or tag - and a
+# filesystem path joined by forward slashes, attempts to separate the two.
+#
+# Expects a @project instance variable to contain the active project. Used to
+# check the input against a list of valid repository refs.
+#
+# Examples
+#
+#   # No @project available
+#   extract_ref('master')
+#   # => ['', '']
+#
+#   extract_ref('master')
+#   # => ['master', '/']
+#
+#   extract_ref("f4b14494ef6abf3d144c28e4af0c20143383e062/CHANGELOG")
+#   # => ['f4b14494ef6abf3d144c28e4af0c20143383e062', '/CHANGELOG']
+#
+#   extract_ref("v2.0.0/README.md")
+#   # => ['v2.0.0', '/README.md']
+#
+#   extract_ref('issues/1234/app/models/project.rb')
+#   # => ['issues/1234', '/app/models/project.rb']
+#
+#   # Given an invalid branch, we fall back to just splitting on the first slash
+#   extract_ref('non/existent/branch/README.md')
+#   # => ['non', '/existent/branch/README.md']
+#
+# Returns an Array where the first value is the tree-ish and the second is the
+# path
+module RefExtractor
+  def extract_ref(input)
+    pair = ['', '']
+
+    return pair unless @project
+
+    if input.match(/^([[:alnum:]]{40})(.+)/)
+      # If the ref appears to be a SHA, we're done, just split the string
+      pair = $~.captures
+    else
+      # Append a trailing slash if we only get a ref and no file path
+      id = input
+      id += '/' unless id.include?('/')
+
+      # Otherwise, attempt to detect the ref using a list of the project's
+      # branches and tags
+      valid_refs = @project.branches + @project.tags
+      valid_refs.select! { |v| id.start_with?("#{v}/") }
+
+      if valid_refs.length != 1
+        # No exact ref match, so just try our best
+        pair = id.match(/([^\/]+)(.+)/).captures
+      else
+        # Partition the string into the ref and the path, ignoring the empty first value
+        pair = id.partition(valid_refs.first)[1..-1]
+      end
+    end
+
+    pair
+  end
+end
@@ -0,0 +1,39 @@
+require 'spec_helper'
+
+describe RefExtractor do
+  include RefExtractor
+
+  let(:project) { double('project') }
+
+  before do
+    @project = project
+    project.stub(:branches).and_return(['master', 'foo/bar/baz'])
+    project.stub(:tags).and_return(['v1.0.0', 'v2.0.0'])
+  end
+
+  it "extracts a ref without a path" do
+    extract_ref('master').should == ['master', '/']
+  end
+
+  it "extracts a valid branch ref" do
+    extract_ref('foo/bar/baz/CHANGELOG').should == ['foo/bar/baz', '/CHANGELOG']
+  end
+
+  it "extracts a valid tag ref" do
+    extract_ref('v2.0.0/CHANGELOG').should == ['v2.0.0', '/CHANGELOG']
+  end
+
+  it "extracts a valid commit ref" do
+    extract_ref('f4b14494ef6abf3d144c28e4af0c20143383e062/CHANGELOG').should ==
+      ['f4b14494ef6abf3d144c28e4af0c20143383e062', '/CHANGELOG']
+  end
+
+  it "falls back to a primitive split for an invalid ref" do
+    extract_ref('stable/CHANGELOG').should == ['stable', '/CHANGELOG']
+  end
+
+  it "returns an empty pair when no @project is set" do
+    @project = nil
+    extract_ref('master/CHANGELOG').should == ['', '']
+  end
+end
...	...	@@ -0,0 +1,64 @@
	1	+# Module providing an extract_ref method for controllers working with Git
	2	+# tree-ish + path params
	3	+#
	4	+# Given a string containing both a Git ref - such as a branch or tag - and a
	5	+# filesystem path joined by forward slashes, attempts to separate the two.
	6	+#
	7	+# Expects a @project instance variable to contain the active project. Used to
	8	+# check the input against a list of valid repository refs.
	9	+#
	10	+# Examples
	11	+#
	12	+# # No @project available
	13	+# extract_ref('master')
	14	+# # => ['', '']
	15	+#
	16	+# extract_ref('master')
	17	+# # => ['master', '/']
	18	+#
	19	+# extract_ref("f4b14494ef6abf3d144c28e4af0c20143383e062/CHANGELOG")
	20	+# # => ['f4b14494ef6abf3d144c28e4af0c20143383e062', '/CHANGELOG']
	21	+#
	22	+# extract_ref("v2.0.0/README.md")
	23	+# # => ['v2.0.0', '/README.md']
	24	+#
	25	+# extract_ref('issues/1234/app/models/project.rb')
	26	+# # => ['issues/1234', '/app/models/project.rb']
	27	+#
	28	+# # Given an invalid branch, we fall back to just splitting on the first slash
	29	+# extract_ref('non/existent/branch/README.md')
	30	+# # => ['non', '/existent/branch/README.md']
	31	+#
	32	+# Returns an Array where the first value is the tree-ish and the second is the
	33	+# path
	34	+module RefExtractor
	35	+ def extract_ref(input)
	36	+ pair = ['', '']
	37	+
	38	+ return pair unless @project
	39	+
	40	+ if input.match(/^([[:alnum:]]{40})(.+)/)
	41	+ # If the ref appears to be a SHA, we're done, just split the string
	42	+ pair = $~.captures
	43	+ else
	44	+ # Append a trailing slash if we only get a ref and no file path
	45	+ id = input
	46	+ id += '/' unless id.include?('/')
	47	+
	48	+ # Otherwise, attempt to detect the ref using a list of the project's
	49	+ # branches and tags
	50	+ valid_refs = @project.branches + @project.tags
	51	+ valid_refs.select! { \|v\| id.start_with?("#{v}/") }
	52	+
	53	+ if valid_refs.length != 1
	54	+ # No exact ref match, so just try our best
	55	+ pair = id.match(/([^\/]+)(.+)/).captures
	56	+ else
	57	+ # Partition the string into the ref and the path, ignoring the empty first value
	58	+ pair = id.partition(valid_refs.first)[1..-1]
	59	+ end
	60	+ end
	61	+
	62	+ pair
	63	+ end
	64	+end
...	...
...	...	@@ -0,0 +1,39 @@
	1	+require 'spec_helper'
	2	+
	3	+describe RefExtractor do
	4	+ include RefExtractor
	5	+
	6	+ let(:project) { double('project') }
	7	+
	8	+ before do
	9	+ @project = project
	10	+ project.stub(:branches).and_return(['master', 'foo/bar/baz'])
	11	+ project.stub(:tags).and_return(['v1.0.0', 'v2.0.0'])
	12	+ end
	13	+
	14	+ it "extracts a ref without a path" do
	15	+ extract_ref('master').should == ['master', '/']
	16	+ end
	17	+
	18	+ it "extracts a valid branch ref" do
	19	+ extract_ref('foo/bar/baz/CHANGELOG').should == ['foo/bar/baz', '/CHANGELOG']
	20	+ end
	21	+
	22	+ it "extracts a valid tag ref" do
	23	+ extract_ref('v2.0.0/CHANGELOG').should == ['v2.0.0', '/CHANGELOG']
	24	+ end
	25	+
	26	+ it "extracts a valid commit ref" do
	27	+ extract_ref('f4b14494ef6abf3d144c28e4af0c20143383e062/CHANGELOG').should ==
	28	+ ['f4b14494ef6abf3d144c28e4af0c20143383e062', '/CHANGELOG']
	29	+ end
	30	+
	31	+ it "falls back to a primitive split for an invalid ref" do
	32	+ extract_ref('stable/CHANGELOG').should == ['stable', '/CHANGELOG']
	33	+ end
	34	+
	35	+ it "returns an empty pair when no @project is set" do
	36	+ @project = nil
	37	+ extract_ref('master/CHANGELOG').should == ['', '']
	38	+ end
	39	+end
...	...