[gnome-builder] util: add IdeLineReader utility structure

[Christian Hergert <chergert src gnome org>]

commit 401dafe5dd9f5d49a449b3db8999ae6bbc406510
Author: Christian Hergert <christian hergert me>
Date:   Fri May 15 16:00:26 2015 -0700

    util: add IdeLineReader utility structure
    
    It's pretty common to have to walk through a file a line at a time, so
    lets make this more abstract. It's also helpful when you want to zero
    line endings to turn a contiguous buffer into a bunch of smaller strings.

 libide/Makefile.am               |    2 +
 libide/autotools/ide-makecache.c |   71 +++--------------------------
 libide/util/ide-line-reader.c    |   91 ++++++++++++++++++++++++++++++++++++++
 libide/util/ide-line-reader.h    |   41 +++++++++++++++++
 4 files changed, 141 insertions(+), 64 deletions(-)
---
diff --git a/libide/Makefile.am b/libide/Makefile.am
index 348c717..95304a9 100644
--- a/libide/Makefile.am
+++ b/libide/Makefile.am
@@ -306,6 +306,8 @@ libide_1_0_la_SOURCES = \
        util/ide-cairo.h \
        util/ide-doc-seq.c \
        util/ide-doc-seq.h \
+       util/ide-line-reader.c \
+       util/ide-line-reader.h \
        util/ide-pango.c \
        util/ide-pango.h \
        util/ide-rgba.c \
diff --git a/libide/autotools/ide-makecache.c b/libide/autotools/ide-makecache.c
index 4d2cca5..cd6dbad 100644
--- a/libide/autotools/ide-makecache.c
+++ b/libide/autotools/ide-makecache.c
@@ -40,6 +40,7 @@
 #include "ide-makecache.h"
 #include "ide-makecache-target.h"
 #include "ide-project.h"
+#include "ide-line-reader.h"
 #include "ide-thread-pool.h"
 #include "ide-vcs.h"
 
@@ -72,13 +73,6 @@ typedef struct
   gchar       *path;
 } FileTargetsLookup;
 
-typedef struct
-{
-  const gchar *contents;
-  gsize        length;
-  gssize       pos;
-} ReadLines;
-
 G_DEFINE_TYPE (IdeMakecache, ide_makecache, IDE_TYPE_OBJECT)
 
 EGG_DEFINE_COUNTER (instances, "IdeMakecache", "Instances", "The number of IdeMakecache")
@@ -92,60 +86,6 @@ enum {
 static GParamSpec *gParamSpecs [LAST_PROP];
 
 static void
-read_lines_init (ReadLines   *rl,
-                 const gchar *contents,
-                 gsize        length)
-{
-  g_assert (rl);
-  g_assert (contents);
-
-  if (length < G_MAXSIZE)
-    {
-      rl->contents = contents;
-      rl->length = length;
-      rl->pos = 0;
-    }
-  else
-    {
-      rl->contents = NULL;
-      rl->length = 0;
-      rl->pos = 0;
-    }
-}
-
-static const gchar *
-read_lines_next (ReadLines *rl,
-                 gsize     *length)
-{
-  const gchar *ret = NULL;
-
-  g_assert (rl);
-  g_assert (length);
-
-  if ((rl->contents == NULL) || (rl->pos >= rl->length))
-    {
-      *length = 0;
-      return NULL;
-    }
-
-  ret = &rl->contents [rl->pos];
-
-  for (; rl->pos < rl->length; rl->pos++)
-    {
-      if (rl->contents [rl->pos] == '\n')
-        {
-          *length = &rl->contents [rl->pos] - ret;
-          rl->pos++;
-          return ret;
-        }
-    }
-
-  *length = &rl->contents [rl->pos] - ret;
-
-  return ret;
-}
-
-static void
 file_flags_lookup_free (gpointer data)
 {
   FileFlagsLookup *lookup = data;
@@ -321,7 +261,7 @@ ide_makecache_get_file_targets_searched (GMappedFile *mapped,
   g_autoptr(GRegex) regex = NULL;
   const gchar *content;
   const gchar *line;
-  ReadLines rl = { 0 };
+  IdeLineReader rl;
   gsize len;
   gsize line_len;
 
@@ -359,9 +299,12 @@ ide_makecache_get_file_targets_searched (GMappedFile *mapped,
   }
 #endif
 
-  read_lines_init (&rl, content, len);
+  if (len > G_MAXSSIZE)
+    IDE_RETURN (NULL);
+
+  ide_line_reader_init (&rl, (gchar *)content, len);
 
-  while ((line = read_lines_next (&rl, &line_len)))
+  while ((line = ide_line_reader_next (&rl, &line_len)))
     {
       /*
        * Keep track of "subdir = <dir>" changes so we know what directory
diff --git a/libide/util/ide-line-reader.c b/libide/util/ide-line-reader.c
new file mode 100644
index 0000000..690db7c
--- /dev/null
+++ b/libide/util/ide-line-reader.c
@@ -0,0 +1,91 @@
+/* ide-line-reader.c
+ *
+ * Copyright (C) 2015 Christian Hergert <christian hergert me>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define G_LOG_DOMAIN "ide-line-reader"
+
+#include <string.h>
+
+#include "ide-line-reader.h"
+
+void
+ide_line_reader_init (IdeLineReader *reader,
+                      gchar         *contents,
+                      gssize         length)
+{
+  g_assert (reader);
+
+  if (length < 0)
+    length = strlen (contents);
+
+  if ((contents != NULL) && (length <= G_MAXSSIZE))
+    {
+      reader->contents = contents;
+      reader->length = length;
+      reader->pos = 0;
+    }
+  else
+    {
+      reader->contents = NULL;
+      reader->length = 0;
+      reader->pos = 0;
+    }
+}
+
+/**
+ * ide_line_reader_next:
+ * @reader: the #IdeLineReader
+ * @length: a location for the length of the line in bytes.
+ *
+ * Moves forward to the beginning of the next line in the buffer. No changes to the buffer
+ * are made, and the result is a pointer within the string passed as @contents in
+ * ide_line_reader_init(). Since the line most likely will not be terminated with a NULL byte,
+ * you must provide @length to determine the length of the line.
+ *
+ * Returns: (transfer none): The beginning of the line within the buffer.
+ */
+gchar *
+ide_line_reader_next (IdeLineReader *reader,
+                      gsize         *length)
+{
+  gchar *ret = NULL;
+
+  g_assert (reader);
+  g_assert (length != NULL);
+
+  if ((reader->contents == NULL) || (reader->pos >= reader->length))
+    {
+      *length = 0;
+      return NULL;
+    }
+
+  ret = &reader->contents [reader->pos];
+
+  for (; reader->pos < reader->length; reader->pos++)
+    {
+      if (reader->contents [reader->pos] == '\n')
+        {
+          *length = &reader->contents [reader->pos] - ret;
+          reader->pos++;
+          return ret;
+        }
+    }
+
+  *length = &reader->contents [reader->pos] - ret;
+
+  return ret;
+}
diff --git a/libide/util/ide-line-reader.h b/libide/util/ide-line-reader.h
new file mode 100644
index 0000000..aa5d64d
--- /dev/null
+++ b/libide/util/ide-line-reader.h
@@ -0,0 +1,41 @@
+/* ide-line-reader.h
+ *
+ * Copyright (C) 2015 Christian Hergert <christian hergert me>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef IDE_LINE_READER_H
+#define IDE_LINE_READER_H
+
+#include <glib.h>
+
+G_BEGIN_DECLS
+
+typedef struct
+{
+  gchar  *contents;
+  gsize   length;
+  gssize  pos;
+} IdeLineReader;
+
+void   ide_line_reader_init (IdeLineReader *reader,
+                             gchar         *contents,
+                             gssize         length);
+gchar *ide_line_reader_next (IdeLineReader *reader,
+                             gsize         *length);
+
+G_END_DECLS
+
+#endif /* IDE_LINE_READER_H */