<p>Neels Hofmeyr has uploaded this change for <strong>review</strong>.</p><p><a href="https://gerrit.osmocom.org/13394">View Change</a></p><pre style="font-family: monospace,monospace; white-space: pre-wrap;">add osmo_str_startswith()<br><br>Move from a static implementation in tdef_vty.c to utils.c, I also want to use<br>this in osmo-msc.<br><br>The point is that the telnet VTY allows unambiguous partly matches of keyword<br>args. For example, if I have a command definition of:<br><br> compare (apples|oranges)<br><br>then it is perfectly legal as for the vty parser to write only<br><br> compare app<br><br>One could expect the VTY to then pass the unambiguous match of "apples" to the<br>parsing function, but that is not the case.<br><br>Hence a VTY function implementation is faced with parsing a keyword of "app"<br>instead of the expected "apples".<br><br>This is actually a very widespread bug in our VTY implementations, which assume<br>that exactly one full keyword will always be found. I am now writing new<br>commands in a way that are able to manage only the starts of keywords.<br><br>Arguably, strstr(a, b) == a does the same thing, but it searches the entire<br>string unnecessarily.<br><br>Change-Id: Ib2ffb0e9a870dd52e081c7e66d8818057d159513<br>---<br>M include/osmocom/core/utils.h<br>M src/utils.c<br>M src/vty/tdef_vty.c<br>M tests/utils/utils_test.c<br>M tests/utils/utils_test.ok<br>5 files changed, 60 insertions(+), 11 deletions(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;">git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/94/13394/1</pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;"><span>diff --git a/include/osmocom/core/utils.h b/include/osmocom/core/utils.h</span><br><span>index 16159d3..31ef49b 100644</span><br><span>--- a/include/osmocom/core/utils.h</span><br><span>+++ b/include/osmocom/core/utils.h</span><br><span>@@ -230,4 +230,6 @@</span><br><span> #define OSMO_STRBUF_PRINTF(STRBUF, fmt, args...) \</span><br><span> OSMO_STRBUF_APPEND(STRBUF, snprintf, fmt, ##args)</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+bool osmo_str_startswith(const char *str, const char *startswith_str);</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> /*! @} */</span><br><span>diff --git a/src/utils.c b/src/utils.c</span><br><span>index 2d5bcb0..fb4e71e 100644</span><br><span>--- a/src/utils.c</span><br><span>+++ b/src/utils.c</span><br><span>@@ -826,4 +826,18 @@</span><br><span> return (sum * 9) % 10 + '0';</span><br><span> }</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+/*! Compare start of a string.</span><br><span style="color: hsl(120, 100%, 40%);">+ * This is an optimisation of 'strstr(str, startswith_str) == str' because it doesn't search through the entire string.</span><br><span style="color: hsl(120, 100%, 40%);">+ * \param str (Longer) string to compare.</span><br><span style="color: hsl(120, 100%, 40%);">+ * \param startswith_str (Shorter) string to compare with the start of str.</span><br><span style="color: hsl(120, 100%, 40%);">+ * \return true iff the first characters of str fully match startswith_str or startswith_str is empty. */</span><br><span style="color: hsl(120, 100%, 40%);">+bool osmo_str_startswith(const char *str, const char *startswith_str)</span><br><span style="color: hsl(120, 100%, 40%);">+{</span><br><span style="color: hsl(120, 100%, 40%);">+ if (!startswith_str || !*startswith_str)</span><br><span style="color: hsl(120, 100%, 40%);">+ return true;</span><br><span style="color: hsl(120, 100%, 40%);">+ if (!str)</span><br><span style="color: hsl(120, 100%, 40%);">+ return false;</span><br><span style="color: hsl(120, 100%, 40%);">+ return strncmp(str, startswith_str, strlen(startswith_str)) == 0;</span><br><span style="color: hsl(120, 100%, 40%);">+}</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> /*! @} */</span><br><span>diff --git a/src/vty/tdef_vty.c b/src/vty/tdef_vty.c</span><br><span>index 28de21a..0dac2bf 100644</span><br><span>--- a/src/vty/tdef_vty.c</span><br><span>+++ b/src/vty/tdef_vty.c</span><br><span>@@ -247,16 +247,6 @@</span><br><span> /*! Singleton Tnnn groups definition as set by osmo_tdef_vty_groups_init(). */</span><br><span> static struct osmo_tdef_group *global_tdef_groups;</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">-/*! \return true iff the first characters of str fully match startswith_str or both are empty. */</span><br><span style="color: hsl(0, 100%, 40%);">-static bool startswith(const char *str, const char *startswith_str)</span><br><span style="color: hsl(0, 100%, 40%);">-{</span><br><span style="color: hsl(0, 100%, 40%);">- if (!startswith_str)</span><br><span style="color: hsl(0, 100%, 40%);">- return true;</span><br><span style="color: hsl(0, 100%, 40%);">- if (!str)</span><br><span style="color: hsl(0, 100%, 40%);">- return false;</span><br><span style="color: hsl(0, 100%, 40%);">- return strncmp(str, startswith_str, strlen(startswith_str)) == 0;</span><br><span style="color: hsl(0, 100%, 40%);">-}</span><br><span style="color: hsl(0, 100%, 40%);">-</span><br><span> DEFUN(show_timer, show_timer_cmd, "DYNAMIC", "DYNAMIC")</span><br><span> /* show timer [(alpha|beta|gamma)] [TNNNN] */</span><br><span> {</span><br><span>@@ -268,7 +258,7 @@</span><br><span> * like "softw" or "t" (which can also be ambiguous). */</span><br><span> </span><br><span> osmo_tdef_groups_for_each(g, global_tdef_groups) {</span><br><span style="color: hsl(0, 100%, 40%);">- if (!group_arg || startswith(g->name, group_arg))</span><br><span style="color: hsl(120, 100%, 40%);">+ if (!group_arg || osmo_str_startswith(g->name, group_arg))</span><br><span> osmo_tdef_vty_show_cmd(vty, g->tdefs, T_arg, "%s: ", g->name);</span><br><span> }</span><br><span> return CMD_SUCCESS;</span><br><span>diff --git a/tests/utils/utils_test.c b/tests/utils/utils_test.c</span><br><span>index d592fe0..9d36c5a 100644</span><br><span>--- a/tests/utils/utils_test.c</span><br><span>+++ b/tests/utils/utils_test.c</span><br><span>@@ -1022,6 +1022,33 @@</span><br><span> printf("(need %d chars, had size=63) %s\n", rc, buf);</span><br><span> }</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+static void startswith_test_str(const char *str, const char *startswith_str, bool expect_rc)</span><br><span style="color: hsl(120, 100%, 40%);">+{</span><br><span style="color: hsl(120, 100%, 40%);">+ bool rc = osmo_str_startswith(str, startswith_str);</span><br><span style="color: hsl(120, 100%, 40%);">+ printf("osmo_str_startswith(%s, ", osmo_quote_str(str, -1));</span><br><span style="color: hsl(120, 100%, 40%);">+ printf("%s) == %s\n", osmo_quote_str(startswith_str, -1), rc ? "true" : "false");</span><br><span style="color: hsl(120, 100%, 40%);">+ if (rc != expect_rc)</span><br><span style="color: hsl(120, 100%, 40%);">+ printf(" ERROR: EXPECTED %s\n", expect_rc ? "true" : "false");</span><br><span style="color: hsl(120, 100%, 40%);">+}</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+static void startswith_test()</span><br><span style="color: hsl(120, 100%, 40%);">+{</span><br><span style="color: hsl(120, 100%, 40%);">+ printf("\n%s()\n", __func__);</span><br><span style="color: hsl(120, 100%, 40%);">+ startswith_test_str(NULL, NULL, true);</span><br><span style="color: hsl(120, 100%, 40%);">+ startswith_test_str("", NULL, true);</span><br><span style="color: hsl(120, 100%, 40%);">+ startswith_test_str(NULL, "", true);</span><br><span style="color: hsl(120, 100%, 40%);">+ startswith_test_str("", "", true);</span><br><span style="color: hsl(120, 100%, 40%);">+ startswith_test_str("abc", NULL, true);</span><br><span style="color: hsl(120, 100%, 40%);">+ startswith_test_str("abc", "", true);</span><br><span style="color: hsl(120, 100%, 40%);">+ startswith_test_str(NULL, "abc", false);</span><br><span style="color: hsl(120, 100%, 40%);">+ startswith_test_str("", "abc", false);</span><br><span style="color: hsl(120, 100%, 40%);">+ startswith_test_str("abc", "a", true);</span><br><span style="color: hsl(120, 100%, 40%);">+ startswith_test_str("abc", "ab", true);</span><br><span style="color: hsl(120, 100%, 40%);">+ startswith_test_str("abc", "abc", true);</span><br><span style="color: hsl(120, 100%, 40%);">+ startswith_test_str("abc", "abcd", false);</span><br><span style="color: hsl(120, 100%, 40%);">+ startswith_test_str("abc", "xyz", false);</span><br><span style="color: hsl(120, 100%, 40%);">+}</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> int main(int argc, char **argv)</span><br><span> {</span><br><span> static const struct log_info log_info = {};</span><br><span>@@ -1040,5 +1067,6 @@</span><br><span> osmo_sockaddr_to_str_and_uint_test();</span><br><span> osmo_str_tolowupper_test();</span><br><span> strbuf_test();</span><br><span style="color: hsl(120, 100%, 40%);">+ startswith_test();</span><br><span> return 0;</span><br><span> }</span><br><span>diff --git a/tests/utils/utils_test.ok b/tests/utils/utils_test.ok</span><br><span>index 1215ddd..3579062 100644</span><br><span>--- a/tests/utils/utils_test.ok</span><br><span>+++ b/tests/utils/utils_test.ok</span><br><span>@@ -342,3 +342,18 @@</span><br><span> (need 134 chars)</span><br><span> T minus 10 9 8 7 6 5 4 3 2 1 ... Lift off! -- T minus 10 9 8 7 6 5 4 3 2 1 ... Lift off! -- T minus 10 9 8 7 6 5 4 3 2 1 ... Lift off!</span><br><span> (need 134 chars, had size=63) T minus 10 9 8 7 6 5 4 3 2 1 ... Lift off! -- T minus 10 9 8 7</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+startswith_test()</span><br><span style="color: hsl(120, 100%, 40%);">+osmo_str_startswith(NULL, NULL) == true</span><br><span style="color: hsl(120, 100%, 40%);">+osmo_str_startswith("", NULL) == true</span><br><span style="color: hsl(120, 100%, 40%);">+osmo_str_startswith(NULL, "") == true</span><br><span style="color: hsl(120, 100%, 40%);">+osmo_str_startswith("", "") == true</span><br><span style="color: hsl(120, 100%, 40%);">+osmo_str_startswith("abc", NULL) == true</span><br><span style="color: hsl(120, 100%, 40%);">+osmo_str_startswith("abc", "") == true</span><br><span style="color: hsl(120, 100%, 40%);">+osmo_str_startswith(NULL, "abc") == false</span><br><span style="color: hsl(120, 100%, 40%);">+osmo_str_startswith("", "abc") == false</span><br><span style="color: hsl(120, 100%, 40%);">+osmo_str_startswith("abc", "a") == true</span><br><span style="color: hsl(120, 100%, 40%);">+osmo_str_startswith("abc", "ab") == true</span><br><span style="color: hsl(120, 100%, 40%);">+osmo_str_startswith("abc", "abc") == true</span><br><span style="color: hsl(120, 100%, 40%);">+osmo_str_startswith("abc", "abcd") == false</span><br><span style="color: hsl(120, 100%, 40%);">+osmo_str_startswith("abc", "xyz") == false</span><br><span></span><br></pre><p>To view, visit <a href="https://gerrit.osmocom.org/13394">change 13394</a>. To unsubscribe, or for help writing mail filters, visit <a href="https://gerrit.osmocom.org/settings">settings</a>.</p><div itemscope itemtype="http://schema.org/EmailMessage"><div itemscope itemprop="action" itemtype="http://schema.org/ViewAction"><link itemprop="url" href="https://gerrit.osmocom.org/13394"/><meta itemprop="name" content="View Change"/></div></div>
<div style="display:none"> Gerrit-Project: libosmocore </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-MessageType: newchange </div>
<div style="display:none"> Gerrit-Change-Id: Ib2ffb0e9a870dd52e081c7e66d8818057d159513 </div>
<div style="display:none"> Gerrit-Change-Number: 13394 </div>
<div style="display:none"> Gerrit-PatchSet: 1 </div>
<div style="display:none"> Gerrit-Owner: Neels Hofmeyr <nhofmeyr@sysmocom.de> </div>