From 9dc946ba67a5d457ce00bf2853f624c3c7c344aa Mon Sep 17 00:00:00 2001
From: Nick Mathewson <nickm@torproject.org>
Date: Wed, 26 Feb 2020 10:10:27 -0500
Subject: Add a config_lines_partition() function to help with LINELIST_V.

This function works a little bit like strsep(), to get a chunk of
configuration lines with a given header.  We can use this to make
hidden service config easier to parse.
---
 src/lib/encoding/confline.c | 29 +++++++++++++++++++++++++++++
 src/lib/encoding/confline.h |  1 +
 2 files changed, 30 insertions(+)

(limited to 'src/lib/encoding')

diff --git a/src/lib/encoding/confline.c b/src/lib/encoding/confline.c
index ff8bacba3c..eb1a4e30f0 100644
--- a/src/lib/encoding/confline.c
+++ b/src/lib/encoding/confline.c
@@ -253,6 +253,35 @@ config_lines_dup_and_filter(const config_line_t *inp,
   return result;
 }
 
+/**
+ * Given a linelist <b>inp</b> beginning with the key <b>header</b>, find the
+ * next line with that key, and remove that instance and all following lines
+ * from the list.  Return the lines that were removed.  Operate
+ * case-insensitively.
+ *
+ * For example, if the header is "H", and <b>inp</b> contains "H, A, B, H, C,
+ * H, D", this function will alter <b>inp</b> to contain only "H, A, B", and
+ * return the elements "H, C, H, D" as a separate list.
+ **/
+config_line_t *
+config_lines_partition(config_line_t *inp, const char *header)
+{
+  if (BUG(inp == NULL))
+    return NULL;
+  if (BUG(strcasecmp(inp->key, header)))
+    return NULL;
+
+  /* Advance ptr until it points to the link to the next segment of this
+     list. */
+  config_line_t **ptr = &inp->next;
+  while (*ptr && strcasecmp((*ptr)->key, header)) {
+    ptr = &(*ptr)->next;
+  }
+  config_line_t *remainder = *ptr;
+  *ptr = NULL;
+  return remainder;
+}
+
 /** Return true iff a and b contain identical keys and values in identical
  * order. */
 int
diff --git a/src/lib/encoding/confline.h b/src/lib/encoding/confline.h
index cd343e0e99..ce0d6c6e17 100644
--- a/src/lib/encoding/confline.h
+++ b/src/lib/encoding/confline.h
@@ -50,6 +50,7 @@ const config_line_t *config_line_find(const config_line_t *lines,
                                       const char *key);
 const config_line_t *config_line_find_case(const config_line_t *lines,
                                            const char *key);
+config_line_t *config_lines_partition(config_line_t *inp, const char *header);
 int config_lines_eq(const config_line_t *a, const config_line_t *b);
 int config_count_key(const config_line_t *a, const char *key);
 void config_free_lines_(config_line_t *front);
-- 
cgit v1.2.3-54-g00ecf