Logging: add MakePDFWarning constructor to LogMessage.

[API change]

Use this to pass LaTeX warnings on to user as warnings.

2 files changed, 23 insertions, 2 deletions

diff --git a/src/Text/Pandoc/Logging.hs b/src/Text/Pandoc/Logging.hs
index 3b5d63049..9245107ee 100644
--- a/src/Text/Pandoc/Logging.hs
+++ b/src/Text/Pandoc/Logging.hs
@@ -100,6 +100,7 @@ data LogMessage =
   | DuplicateAttribute Text Text
   | NotUTF8Encoded FilePath
   | MakePDFInfo Text Text
+  | MakePDFWarning Text
   deriving (Show, Eq, Data, Ord, Typeable, Generic)
 
 instance ToJSON LogMessage where
@@ -257,6 +258,8 @@ instance ToJSON LogMessage where
       MakePDFInfo description contents ->
            ["description" .= description
            ,"contents" .= contents]
+      MakePDFWarning message ->
+           ["message" .= message]
 
 showPos :: SourcePos -> Text
 showPos pos = Text.pack $ sn ++ "line " ++
@@ -396,6 +399,7 @@ showLogMessage msg =
           if Text.null contents
              then mempty
              else "\n" <> contents
+       MakePDFWarning message -> "[makePDF] " <> message
 
 messageVerbosity :: LogMessage -> Verbosity
 messageVerbosity msg =
@@ -450,3 +454,4 @@ messageVerbosity msg =
        DuplicateAttribute{}          -> WARNING
        NotUTF8Encoded{}              -> WARNING
        MakePDFInfo{}                 -> INFO
+       MakePDFWarning{}              -> WARNING
diff --git a/src/Text/Pandoc/PDF.hs b/src/Text/Pandoc/PDF.hs
index 2cef4404e..060262449 100644
--- a/src/Text/Pandoc/PDF.hs
+++ b/src/Text/Pandoc/PDF.hs
@@ -19,6 +19,7 @@ module Text.Pandoc.PDF ( makePDF ) where
 import qualified Codec.Picture as JP
 import qualified Control.Exception as E
 import Control.Monad.Trans (MonadIO (..))
+import Control.Monad (foldM_)
 import qualified Data.ByteString as BS
 import Data.ByteString.Lazy (ByteString)
 import qualified Data.ByteString.Lazy as BL
@@ -38,7 +39,7 @@ import System.IO (hClose)
 import System.IO.Temp (withSystemTempDirectory, withTempDirectory,
                        withTempFile)
 import qualified System.IO.Error as IE
-import Text.DocLayout (literal)
+import Text.DocLayout (literal, render, hsep)
 import Text.Pandoc.Definition
 import Text.Pandoc.Error (PandocError (PandocPDFProgramNotFoundError))
 import Text.Pandoc.MIME (getMimeType)
@@ -286,13 +287,14 @@ tex2pdf program args tmpDir' source = do
           return $ Left $ logmsg <> extramsg
        (ExitSuccess, Nothing)  -> return $ Left ""
        (ExitSuccess, Just pdf) -> do
+          latexWarnings log'
           missingCharacterWarnings log'
           return $ Right pdf
 
 missingCharacterWarnings :: PandocMonad m => ByteString -> m ()
 missingCharacterWarnings log' = do
   let ls = BC.lines log'
-  let isMissingCharacterWarning = BC.isPrefixOf "Missing character: "
+  let isMissingCharacterWarning = BC.isPrefixOf "Missing character:"
   let toCodePoint c
         | isAscii c   = T.singleton c
         | otherwise   = T.pack $ c : " (U+" ++ printf "%04X" (ord c) ++ ")"
@@ -303,6 +305,20 @@ missingCharacterWarnings log' = do
                  ]
   mapM_ (report . MissingCharacter) warnings
 
+latexWarnings :: PandocMonad m => ByteString -> m ()
+latexWarnings log' = foldM_ go Nothing (BC.lines log')
+ where
+   go Nothing ln
+     | BC.isPrefixOf "LaTeX Warning:" ln =
+       pure $ Just ln
+     | otherwise = pure Nothing
+   go (Just msg) ln
+     | ln == "" = do -- emit report and reset accumulator
+         report $ MakePDFWarning $ render (Just 60) $
+            hsep $ map literal $ T.words $ UTF8.toText $ BC.toStrict msg
+         pure Nothing
+     | otherwise = pure $ Just (msg <> ln)
+
 -- parsing output
 
 extractMsg :: ByteString -> ByteString