util: buffer: Add support for adding text blocks with indentation

The current auto-indentation buffer code applies indentation only on
complete strings. To allow adding a string containing newlines and
having it properly indented this patch adds virBufferAddStr.

(cherry picked from commit 6ff59cbc83)

src/libvirt_private.syms

@@ -1083,6 +1083,7 @@ virBitmapToData;
 virBufferAdd;
 virBufferAddBuffer;
 virBufferAddChar;
+virBufferAddStr;
 virBufferAdjustIndent;
 virBufferAsprintf;
 virBufferCheckErrorInternal;

src/util/virbuffer.c

@@ -752,3 +752,32 @@ virBufferTrim(virBufferPtr buf, const char *str, int len)
     buf->use -= len < 0 ? len2 : len;
     buf->content[buf->use] = '\0';
 }
+
+
+/**
+ * virBufferAddStr:
+ * @buf: the buffer to append to
+ * @str: string to append
+ *
+ * Appends @str to @buffer. Applies autoindentation on the separate lines of
+ * @str.
+ */
+void
+virBufferAddStr(virBufferPtr buf,
+                const char *str)
+{
+    const char *end;
+
+    if (!buf || !str || buf->error)
+        return;
+
+    while (*str) {
+        if ((end = strchr(str, '\n'))) {
+            virBufferAdd(buf, str, (end - str) + 1);
+            str = end + 1;
+        } else {
+            virBufferAdd(buf, str, -1);
+            break;
+        }
+    }
+}

src/util/virbuffer.h

@@ -96,5 +96,6 @@ void virBufferAdjustIndent(virBufferPtr buf, int indent);
 int virBufferGetIndent(const virBuffer *buf, bool dynamic);
 
 void virBufferTrim(virBufferPtr buf, const char *trim, int len);
+void virBufferAddStr(virBufferPtr buf, const char *str);
 
 #endif /* __VIR_BUFFER_H__ */

tests/virbuftest.c

@@ -310,6 +310,43 @@ static int testBufAddBuffer(const void *data ATTRIBUTE_UNUSED)
     return ret;
 }
 
+struct testBufAddStrData {
+    const char *data;
+    const char *expect;
+};
+
+static int
+testBufAddStr(const void *opaque ATTRIBUTE_UNUSED)
+{
+    const struct testBufAddStrData *data = opaque;
+    virBuffer buf = VIR_BUFFER_INITIALIZER;
+    char *actual;
+    int ret = -1;
+
+    virBufferAddLit(&buf, "<c>\n");
+    virBufferAdjustIndent(&buf, 2);
+    virBufferAddStr(&buf, data->data);
+    virBufferAdjustIndent(&buf, -2);
+    virBufferAddLit(&buf, "</c>");
+
+    if (!(actual = virBufferContentAndReset(&buf))) {
+        TEST_ERROR("buf is empty");
+        goto cleanup;
+    }
+
+    if (STRNEQ_NULLABLE(actual, data->expect)) {
+        TEST_ERROR("testBufAddStr(): Strings don't match:\n");
+        virtTestDifference(stderr, data->expect, actual);
+        goto cleanup;
+    }
+
+    ret = 0;
+
+ cleanup:
+    VIR_FREE(actual);
+    return ret;
+}
+
 
 static int
 mymain(void)
@@ -330,6 +367,18 @@ mymain(void)
     DO_TEST("Trim", testBufTrim, 0);
     DO_TEST("AddBuffer", testBufAddBuffer, 0);
 
+#define DO_TEST_ADD_STR(DATA, EXPECT)                                  \
+    do {                                                               \
+        struct testBufAddStrData info = { DATA, EXPECT };              \
+        if (virtTestRun("Buf: AddStr", testBufAddStr, &info) < 0)      \
+            ret = -1;                                                  \
+    } while (0)
+
+    DO_TEST_ADD_STR("", "<c>\n</c>");
+    DO_TEST_ADD_STR("<a/>", "<c>\n  <a/></c>");
+    DO_TEST_ADD_STR("<a/>\n", "<c>\n  <a/>\n</c>");
+    DO_TEST_ADD_STR("<b>\n  <a/>\n</b>\n", "<c>\n  <b>\n    <a/>\n  </b>\n</c>");
+
     return ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
 }