[tracker] libtracker-data: Handle overflows on libicu-based normalization

[Carlos Garnacho <carlosg src gnome org>]

commit bc73a4878f03ab569641134d860c4b1ffe82a93f
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu Nov 3 01:16:07 2016 +0100

    libtracker-data: Handle overflows on libicu-based normalization
    
    We allocate by default double the string size, which is a pretty
    generous allotment most usually. If that is not enough for storing
    the normalized string, just reallocate the buffer with the given
    expected size and try again.
    
    Also, refactor string normalization to a separate function, so
    it's shared by both tracker:normalize and tracker:unaccent.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=769982

 src/libtracker-data/tracker-db-interface-sqlite.c |   58 ++++++++++++++-------
 1 files changed, 39 insertions(+), 19 deletions(-)
---
diff --git a/src/libtracker-data/tracker-db-interface-sqlite.c 
b/src/libtracker-data/tracker-db-interface-sqlite.c
index ff292eb..fa74f5c 100644
--- a/src/libtracker-data/tracker-db-interface-sqlite.c
+++ b/src/libtracker-data/tracker-db-interface-sqlite.c
@@ -1028,6 +1028,40 @@ function_sparql_case_fold (sqlite3_context *context,
        sqlite3_result_text16 (context, zOutput, -1, sqlite3_free);
 }
 
+static gunichar2 *
+normalize_string (const gunichar2    *string,
+                  gsize               string_len, /* In gunichar2s */
+                  UNormalizationMode  mode,
+                  gsize              *len_out,    /* In gunichar2s */
+                  UErrorCode         *status)
+{
+       int nInput, nOutput;
+       gunichar2 *zOutput;
+
+       nOutput = (string_len * 2) + 1;
+       zOutput = g_new0 (gunichar2, nOutput);
+
+       nOutput = unorm_normalize (string, string_len, mode, 0, zOutput, nOutput, status);
+
+       if (*status == U_BUFFER_OVERFLOW_ERROR) {
+               /* Try again after allocating enough space for the normalization */
+               *status = U_ZERO_ERROR;
+               zOutput = g_renew (gunichar2, zOutput, nOutput);
+               memset (zOutput, 0, nOutput * sizeof (gunichar2));
+               nOutput = unorm_normalize (string, string_len, mode, 0, zOutput, nOutput, status);
+       }
+
+       if (!U_SUCCESS (*status)) {
+               g_clear_pointer (&zOutput, g_free);
+               nOutput = 0;
+       }
+
+       if (len_out)
+               *len_out = nOutput;
+
+       return zOutput;
+}
+
 static void
 function_sparql_normalize (sqlite3_context *context,
                            int              argc,
@@ -1037,7 +1071,7 @@ function_sparql_normalize (sqlite3_context *context,
        const uint16_t *zInput;
        uint16_t *zOutput;
        int nInput;
-       int nOutput;
+       gsize nOutput;
        UNormalizationMode nf;
        UErrorCode status = U_ZERO_ERROR;
 
@@ -1067,15 +1101,8 @@ function_sparql_normalize (sqlite3_context *context,
        }
 
        nInput = sqlite3_value_bytes16 (argv[0]);
+       zOutput = normalize_string (zInput, nInput / 2, nf, &nOutput, &status);
 
-       nOutput = nInput * 2 + 2;
-       zOutput = sqlite3_malloc (nOutput);
-
-       if (!zOutput) {
-               return;
-       }
-
-       unorm_normalize (zInput, nInput/2, nf, 0, zOutput, nOutput/2, &status);
        if (!U_SUCCESS (status)) {
                char zBuf[128];
                sqlite3_snprintf (128, zBuf, "ICU error: unorm_normalize: %s", u_errorName (status));
@@ -1085,7 +1112,7 @@ function_sparql_normalize (sqlite3_context *context,
                return;
        }
 
-       sqlite3_result_text16 (context, zOutput, -1, sqlite3_free);
+       sqlite3_result_text16 (context, zOutput, nOutput * sizeof (gunichar2), g_free);
 }
 
 static void
@@ -1109,15 +1136,8 @@ function_sparql_unaccent (sqlite3_context *context,
        }
 
        nInput = sqlite3_value_bytes16 (argv[0]);
+       zOutput = normalize_string (zInput, nInput / 2, UNORM_NFKD, &nOutput, &status);
 
-       nOutput = nInput * 2 + 2;
-       zOutput = sqlite3_malloc (nOutput);
-
-       if (!zOutput) {
-               return;
-       }
-
-       nOutput = unorm_normalize (zInput, nInput/2, UNORM_NFKD, 0, zOutput, nOutput/2, &status);
        if (!U_SUCCESS (status)) {
                char zBuf[128];
                sqlite3_snprintf (128, zBuf, "ICU error: unorm_normalize: %s", u_errorName (status));
@@ -1130,7 +1150,7 @@ function_sparql_unaccent (sqlite3_context *context,
        /* Unaccenting is done in place */
        tracker_parser_unaccent_nfkd_string (zOutput, &nOutput);
 
-       sqlite3_result_text16 (context, zOutput, -1, sqlite3_free);
+       sqlite3_result_text16 (context, zOutput, nOutput * sizeof (gunichar2), g_free);
 }
 
 #endif