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Re: [PATCH 1/2] Introduce string_appendf/string_vappendf (Re: [RFA 4/6] Simple cleanup removals in remote.c)
On 10/19/2017 04:11 AM, Simon Marchi wrote:
> string_appendf can be implemented using string_vappendf, to reduce
> duplication. It would basically be like string_vappendf_wrapper is. In
> the tests, we can probably just test string_appendf then.
>
> Unless there's a good reason for them not sharing code?
No really good reason. It'd save some branching, I guess.
I've done that now. I still left string_vappendf_wrapper
in place because I think it's better to test both entry points
in case the implementation of string_appendf changes from
the trivial wrapper to something else for some reason. At that
point, the string_vappendf_wrapper can still be left as the
simple wrapper that it is, irrespective of how string_appendf
is implemented.
>> @@ -83,4 +128,6 @@ _initialize_common_utils_selftests ()
>> {
>> selftests::register_test ("string_printf",
>> selftests::string_printf_tests);
>> selftests::register_test ("string_vprintf",
>> selftests::string_vprintf_tests);
>> + selftests::register_test ("string_appendf",
>> selftests::string_appendf_tests);
>> + selftests::register_test ("string_vappendf",
>> selftests::string_vappendf_tests);
>
> The last line is too long.
Fixed. Below's what I pushed.
>From 31b833b3eab69d91df67edc3e9a21792abc3f93e Mon Sep 17 00:00:00 2001
From: Pedro Alves <palves@redhat.com>
Date: Mon, 30 Oct 2017 11:41:34 +0000
Subject: [PATCH] Introduce string_appendf/string_vappendf
string_appendf is like string_printf, but instead of allocating a new
string, it appends to an existing string. This allows reusing a
std::string's memory buffer across several calls, for example.
gdb/ChangeLog:
2017-10-30 Pedro Alves <palves@redhat.com>
* common/common-utils.c (string_appendf, string_vappendf): New
functions.
* common/common-utils.h (string_appendf, string_vappendf): New
declarations.
* unittests/common-utils-selftests.c (string_appendf_func)
(test_appendf_func, string_vappendf_wrapper, string_appendf_tests)
(string_vappendf_tests): New functions.
(_initialize_common_utils_selftests): Register "string_appendf" and
"string_vappendf tests".
---
gdb/ChangeLog | 12 +++++++++
gdb/common/common-utils.c | 34 +++++++++++++++++++++++
gdb/common/common-utils.h | 9 +++++++
gdb/unittests/common-utils-selftests.c | 49 ++++++++++++++++++++++++++++++++++
4 files changed, 104 insertions(+)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 20d78ba..f3abf16 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,17 @@
2017-10-30 Pedro Alves <palves@redhat.com>
+ * common/common-utils.c (string_appendf, string_vappendf): New
+ functions.
+ * common/common-utils.h (string_appendf, string_vappendf): New
+ declarations.
+ * unittests/common-utils-selftests.c (string_appendf_func)
+ (test_appendf_func, string_vappendf_wrapper, string_appendf_tests)
+ (string_vappendf_tests): New functions.
+ (_initialize_common_utils_selftests): Register "string_appendf" and
+ "string_vappendf tests".
+
+2017-10-30 Pedro Alves <palves@redhat.com>
+
* unittests/common-utils-selftests.c (format_func): New typedef.
(string_printf_tests, string_vprintf_tests): Tests factored out
and merged to ...
diff --git a/gdb/common/common-utils.c b/gdb/common/common-utils.c
index d8c546a..7139302 100644
--- a/gdb/common/common-utils.c
+++ b/gdb/common/common-utils.c
@@ -195,6 +195,40 @@ string_vprintf (const char* fmt, va_list args)
return str;
}
+
+/* See documentation in common-utils.h. */
+
+void
+string_appendf (std::string &str, const char *fmt, ...)
+{
+ va_list vp;
+
+ va_start (vp, fmt);
+ string_vappendf (str, fmt, vp);
+ va_end (vp);
+}
+
+
+/* See documentation in common-utils.h. */
+
+void
+string_vappendf (std::string &str, const char *fmt, va_list args)
+{
+ va_list vp;
+ int grow_size;
+
+ va_copy (vp, args);
+ grow_size = vsnprintf (NULL, 0, fmt, vp);
+ va_end (vp);
+
+ size_t curr_size = str.size ();
+ str.resize (curr_size + grow_size);
+
+ /* C++11 and later guarantee std::string uses contiguous memory and
+ always includes the terminating '\0'. */
+ vsprintf (&str[curr_size], fmt, args);
+}
+
char *
savestring (const char *ptr, size_t len)
{
diff --git a/gdb/common/common-utils.h b/gdb/common/common-utils.h
index 19724f9..a32863c 100644
--- a/gdb/common/common-utils.h
+++ b/gdb/common/common-utils.h
@@ -67,6 +67,15 @@ std::string string_printf (const char* fmt, ...)
std::string string_vprintf (const char* fmt, va_list args)
ATTRIBUTE_PRINTF (1, 0);
+/* Like string_printf, but appends to DEST instead of returning a new
+ std::string. */
+void string_appendf (std::string &dest, const char* fmt, ...)
+ ATTRIBUTE_PRINTF (2, 3);
+
+/* Like string_appendf, but takes a va_list. */
+void string_vappendf (std::string &dest, const char* fmt, va_list args)
+ ATTRIBUTE_PRINTF (2, 0);
+
/* Make a copy of the string at PTR with LEN characters
(and add a null character at the end in the copy).
Uses malloc to get the space. Returns the address of the copy. */
diff --git a/gdb/unittests/common-utils-selftests.c b/gdb/unittests/common-utils-selftests.c
index 596406e..0e1d2c6 100644
--- a/gdb/unittests/common-utils-selftests.c
+++ b/gdb/unittests/common-utils-selftests.c
@@ -77,6 +77,52 @@ string_vprintf_tests ()
test_format_func (format);
}
+/* Type of both 'string_appendf' and the 'string_vappendf_wrapper'
+ function below. Used to run the same tests against both
+ string_appendf and string_vappendf. */
+typedef void (string_appendf_func) (std::string &str, const char *fmt, ...)
+ ATTRIBUTE_PRINTF (2, 3);
+
+static void
+test_appendf_func (string_appendf_func *func)
+{
+ std::string str;
+
+ func (str, "%s", "");
+ SELF_CHECK (str == "");
+
+ func (str, "%s", "test");
+ SELF_CHECK (str == "test");
+
+ func (str, "%d", 23);
+ SELF_CHECK (str == "test23");
+
+ func (str, "%s %d %s", "foo", 45, "bar");
+ SELF_CHECK (str == "test23foo 45 bar");
+}
+
+static void ATTRIBUTE_PRINTF (2, 3)
+string_vappendf_wrapper (std::string &str, const char *fmt, ...)
+{
+ va_list vp;
+
+ va_start (vp, fmt);
+ string_vappendf (str, fmt, vp);
+ va_end (vp);
+}
+
+static void
+string_appendf_tests ()
+{
+ test_appendf_func (string_appendf);
+}
+
+static void
+string_vappendf_tests ()
+{
+ test_appendf_func (string_vappendf_wrapper);
+}
+
} /* namespace selftests */
void
@@ -84,4 +130,7 @@ _initialize_common_utils_selftests ()
{
selftests::register_test ("string_printf", selftests::string_printf_tests);
selftests::register_test ("string_vprintf", selftests::string_vprintf_tests);
+ selftests::register_test ("string_appendf", selftests::string_appendf_tests);
+ selftests::register_test ("string_vappendf",
+ selftests::string_vappendf_tests);
}
--
2.5.5