Add a cache for gradle output

2 files changed, 98 insertions, 26 deletions

diff --git a/bin/flycheck-android-java.py b/bin/flycheck-android-java.py
index 3f0f4bf..6f14425 100644
--- a/bin/flycheck-android-java.py
+++ b/bin/flycheck-android-java.py
@@ -7,21 +7,43 @@ import sys
 import tempfile
 import time
 
-def find_dominating_file(dir, file):
-    """Find directory containing file."""
-    if os.path.exists(os.path.join(dir, file)):
-        return dir
-    return find_dominating_file(os.path.dirname(dir), file)
+def get_gradle_command_and_project_mtime(dir):
+    """Find top-project gradlew or fallback to using gradle on sub-project dir.
+While iterating the paths, also check mtime on build.gradle files"""
+    topdir = dir
+    build_gradle = None
+    gradlew = None
+    mtime = -1
+    while True:
+        test = os.path.join(topdir, 'build.gradle')
+        if os.path.exists(test):
+            if not build_gradle:
+                build_gradle = test
 
-def get_gradle_command(dir):
-    """Find top-project gradlew or fallback to using gradle on sub-project dir."""
-    topdir = find_dominating_file(dir, 'gradlew')
-    if topdir:
-        return [os.path.join(topdir, 'gradlew'), '-p', topdir]
-    topdir = find_dominating_file(dir, 'build.gradle')
-    if topdir:
-        return ['gradle', '-p', topdir]
-    return ['gradle']
+            try:
+                m = os.path.getmtime(test)
+                if m > mtime:
+                    mtime = m
+            except OSError:
+                pass
+
+        test = os.path.join(topdir, 'gradlew')
+        if os.path.exists(test):
+            gradlew = test
+            break
+
+        test = os.path.dirname(topdir)
+        if test == topdir:
+            break
+        topdir = test
+
+    if gradlew:
+        cmd = [gradlew, '-p', topdir]
+    elif build_gradle:
+        cmd = ['gradle', '-p', os.path.dirname(build_gradle)]
+    else:
+        cmd = ['gradle']
+    return (cmd, mtime)
 
 def filter_source_files(files):
     """Remove any item not looking like a Java source file."""
@@ -61,11 +83,31 @@ Otherwise return None."""
             return files[0:i] + files[i + 1:]
     return None
 
-def figure_out_java_compilation(sourcefile, tempfile):
+def figure_out_java_compilation(sessiondir, sourcefile, tempfile):
     """Get options for Java compilation from gradle project and run javac."""
-    cmd = get_gradle_command(os.path.dirname(sourcefile))
-    cmd.extend(['-q', 'flycheckAndroidJava'])
-    output = subprocess.check_output(cmd, universal_newlines=True).split('\n')
+    (cmd, mtime) = get_gradle_command_and_project_mtime(
+        os.path.dirname(sourcefile))
+    output = None
+    if sessiondir != None:
+        cachefile = os.path.join(sessiondir, 'gradle_output')
+        try:
+            if os.path.getmtime(cachefile) >= mtime:
+                with open(cachefile, 'r') as f:
+                    output = f.read()
+        except (OSError, IOError):
+            pass
+
+    if not output:
+        cmd.extend(['-q', 'flycheckAndroidJava'])
+        output = subprocess.check_output(cmd, universal_newlines=True)
+        if sessiondir != None:
+            try:
+                with open(cachefile, 'w') as f:
+                    f.write(output)
+            except IOError:
+                pass
+
+    output = output.split('\n')
     data = None
     for line in output:
         if line == '***':
@@ -102,11 +144,23 @@ def figure_out_java_compilation(sourcefile, tempfile):
                              data['args'], tempfile)
     return 0
 
-if len(sys.argv) == 3:
-    sys.exit(figure_out_java_compilation(os.path.abspath(sys.argv[1]),
-                                         sys.argv[2]))
-elif len(sys.argv) == 2:
-    sys.exit(figure_out_java_compilation(os.path.abspath(sys.argv[1]),
-                                         sys.argv[1]))
-else:
-    sys.exit(-1)
+def main(argv):
+    sessiondir = None
+
+    if len(sys.argv) == 4:
+        sessiondir = sys.argv[1]
+        sourcefile = sys.argv[2]
+        tempfile = sys.argv[3]
+    elif len(sys.argv) == 3:
+        sourcefile = sys.argv[1]
+        tempfile = sys.argv[2]
+    elif len(sys.argv) == 2:
+        sourcefile = sys.argv[1]
+        tempfile = sourcefile
+    else:
+        return -1
+
+    sourcefile = os.path.abspath(sourcefile)
+    return figure_out_java_compilation(sessiondir, sourcefile, tempfile)
+
+sys.exit(main(sys.argv))
diff --git a/flycheck-android-experimental.el b/flycheck-android-experimental.el
index 00e0a4e..181b056 100644
--- a/flycheck-android-experimental.el
+++ b/flycheck-android-experimental.el
@@ -11,10 +11,14 @@
 
 (require 'flycheck)
 
+(defvar flycheck-android-sessiondir nil
+  "Session directory used for caching.")
+
 (flycheck-define-checker android-java
   "Java syntax checker using javac."
   :command ("python"
             (eval (flycheck-android-find-tool "java"))
+            (eval (flycheck-android-get-sessiondir))
             (eval buffer-file-name)
             source)
   :error-patterns
@@ -37,6 +41,20 @@ TOOL=name of tool"
      (concat (file-name-directory (symbol-file 'flycheck-android-find-tool))
              (file-name-as-directory "bin")))))
 
+(defun flycheck-android-remove-sessiondir ()
+  "Delete session dir if it exists and unsets the variable."
+  (when flycheck-android-sessiondir
+    (delete-directory flycheck-android-sessiondir t)
+    (setq flycheck-android-sessiondir nil)))
+
+(defun flycheck-android-get-sessiondir ()
+  "Return sessiondir if already set otherwise create and set it."
+  (or flycheck-android-sessiondir
+      (progn
+        (add-hook 'kill-emacs-hook 'flycheck-android-remove-sessiondir)
+        (setq flycheck-android-sessiondir
+              (make-temp-file "flycheck-android" t)))))
+
 (add-to-list 'flycheck-checkers 'android-java)
 
 (provide 'flycheck-android-experimental)