From 17d74c488353b1d14fe52caf7bd30e5cde1e5cce Mon Sep 17 00:00:00 2001
From: Corey Johnson & Nathan Sobo <cj+nathan@github.com>
Date: Fri, 26 Oct 2012 12:09:51 -0600
Subject: [PATCH] Detect softTabs/hardTabs when an `EditSession` is created

---
 spec/app/buffer-spec.coffee       |  9 +++++++++
 spec/app/edit-session-spec.coffee | 12 +++++++++++-
 src/app/buffer.coffee             |  6 ++++++
 src/app/edit-session.coffee       |  4 ++--
 4 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/spec/app/buffer-spec.coffee b/spec/app/buffer-spec.coffee
index ec9de0b84..3aa9340db 100644
--- a/spec/app/buffer-spec.coffee
+++ b/spec/app/buffer-spec.coffee
@@ -628,3 +628,12 @@ describe 'Buffer', ->
         buffer.delete([[3, 0], [5, 0]])
         expect(destroyHandler).toHaveBeenCalled()
         expect(buffer.getAnchors().indexOf(anchor)).toBe -1
+
+  describe ".usesSoftTabs()", ->
+    it "returns true if the first indented line begins with tabs", ->
+      buffer.setText("function() {\n  foo();\n}")
+      expect(buffer.usesSoftTabs()).toBeTruthy()
+      buffer.setText("function() {\n\tfoo();\n}")
+      expect(buffer.usesSoftTabs()).toBeFalsy()
+      buffer.setText("")
+      expect(buffer.usesSoftTabs()).toBeUndefined()
diff --git a/spec/app/edit-session-spec.coffee b/spec/app/edit-session-spec.coffee
index 69a06e1cb..abb3d854f 100644
--- a/spec/app/edit-session-spec.coffee
+++ b/spec/app/edit-session-spec.coffee
@@ -10,7 +10,6 @@ describe "EditSession", ->
     buffer.setText(buffer.getText().replace(/[ ]{2}/g, "\t"))
 
   beforeEach ->
-    buffer = new Buffer()
     editSession = fixturesProject.buildEditSessionForPath('sample.js', autoIndent: false)
     buffer = editSession.buffer
     lineLengths = buffer.getLines().map (line) -> line.length
@@ -1745,3 +1744,14 @@ describe "EditSession", ->
       editSession.setSelectedBufferRange([[0, 1], [0, 4]])
       editSession.transpose()
       expect(editSession.lineForBufferRow(0)).toBe 'xcbaz'
+
+  describe "soft-tabs detection", ->
+    it "assign soft / hard tabs based on the contents of the buffer, or uses the default if unknown", ->
+      editSession = fixturesProject.buildEditSessionForPath('sample.js', softTabs: false)
+      expect(editSession.softTabs).toBeTruthy()
+
+      editSession = fixturesProject.buildEditSessionForPath('sample-with-tabs.coffee', softTabs: true)
+      expect(editSession.softTabs).toBeFalsy()
+
+      editSession = fixturesProject.buildEditSessionForPath(null, softTabs: false)
+      expect(editSession.softTabs).toBeFalsy()
diff --git a/src/app/buffer.coffee b/src/app/buffer.coffee
index a7f10bd99..152cba605 100644
--- a/src/app/buffer.coffee
+++ b/src/app/buffer.coffee
@@ -352,6 +352,12 @@ class Buffer
         return row unless @isRowBlank(row)
     null
 
+  usesSoftTabs: ->
+    for line in @getLines()
+      if match = line.match(/^\s/)
+        return match[0][0] != '\t'
+    undefined
+
   logLines: (start=0, end=@getLastRow())->
     for row in [start..end]
       line = @lineForRow(row)
diff --git a/src/app/edit-session.coffee b/src/app/edit-session.coffee
index 262607744..7c94d928c 100644
--- a/src/app/edit-session.coffee
+++ b/src/app/edit-session.coffee
@@ -39,9 +39,9 @@ class EditSession
   softTabs: true
   softWrap: false
 
-  constructor: ({@project, @buffer, @tabLength, @autoIndent, @softTabs, @softWrap }) ->
+  constructor: ({@project, @buffer, @tabLength, @autoIndent, softTabs, @softWrap }) ->
     @id = @constructor.idCounter++
-    @softTabs ?= true
+    @softTabs = @buffer.usesSoftTabs() ? softTabs ? true
     @languageMode = new LanguageMode(this, @buffer.getExtension())
     @displayBuffer = new DisplayBuffer(@buffer, { @languageMode, @tabLength })
     @tokenizedBuffer = @displayBuffer.tokenizedBuffer