patch: support for patches without dates and generated with -U1; shrink

function                                             old     new   delta
extract_filename                                       -      92     +92
extract_filename_and_free_line                        70       -     -70
patch_main                                          1096    1009     -87
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 0/1 up/down: 92/-157)           Total: -65 bytes

diff --git a/editors/patch.c b/editors/patch.c
index e0fb58f..7b39160 100644 (file)
--- a/editors/patch.c
+++ b/editors/patch.c
@@ -44,23 +44,23 @@ static unsigned copy_lines(FILE *src_stream, FILE *dest_stream, unsigned lines_c
  * returns malloc'ed filename
  * NB: frees 1st argument!
  */
-static char *extract_filename_and_free_line(char *line, int patch_level)
+static char *extract_filename(char *line, int patch_level, const char *pat)
 {
-       char *temp, *filename_start_ptr = line + 4;
+       char *temp = NULL, *filename_start_ptr = line + 4;
 
-       /* Terminate string at end of source filename */
-       temp = strchrnul(filename_start_ptr, '\t');
-       *temp = '\0';
+       if (strncmp(line, pat, 4) == 0) {
+               /* Terminate string at end of source filename */
+               line[strcspn(line,"\t\n\r")] = '\0';
 
-       /* Skip over (patch_level) number of leading directories */
-       while (patch_level--) {
-               temp = strchr(filename_start_ptr, '/');
-               if (!temp)
-                       break;
-               filename_start_ptr = temp + 1;
+               /* Skip over (patch_level) number of leading directories */
+               while (patch_level--) {
+                       temp = strchr(filename_start_ptr, '/');
+                       if (!temp)
+                               break;
+                       filename_start_ptr = temp + 1;
+               }
+               temp = xstrdup(filename_start_ptr);
        }
-
-       temp = xstrdup(filename_start_ptr);
        free(line);
        return temp;
 }
@@ -100,30 +100,26 @@ int patch_main(int argc ATTRIBUTE_UNUSED, char **argv)
                /* Skip everything upto the "---" marker
                 * No need to parse the lines "Only in <dir>", and "diff <args>"
                 */
-               while (strncmp(patch_line, "--- ", 4) != 0) {
-                       free(patch_line);
+               do {
+                       /* Extract the filename used before the patch was generated */
+                       original_filename = extract_filename(patch_line, patch_level, "--- ");
                        patch_line = xmalloc_getline(patch_file);
-                       if (!patch_line)
-                               bb_error_msg_and_die("invalid patch");
-               }
-
-               /* Extract the filename used before the patch was generated */
-               original_filename = extract_filename_and_free_line(patch_line, patch_level);
+                       if (!patch_line) goto quit;
+               } while (!original_filename);
 
-               patch_line = xmalloc_getline(patch_file);
-               if (!patch_line || strncmp(patch_line, "+++ ", 4) != 0)
+               new_filename = extract_filename(patch_line, patch_level, "+++ ");
+               if (!new_filename) {
                        bb_error_msg_and_die("invalid patch");
-               new_filename = extract_filename_and_free_line(patch_line, patch_level);
+               }
 
-               /* Get access rights from the file to be patched, -1 file does not exist */
+               /* Get access rights from the file to be patched */
                if (stat(new_filename, &saved_stat) != 0) {
-                       char *line_ptr;
-                       /* Create leading directories */
-                       line_ptr = strrchr(new_filename, '/');
-                       if (line_ptr) {
-                               *line_ptr = '\0';
+                       char *slash = strrchr(new_filename, '/');
+                       if (slash) {
+                               /* Create leading directories */
+                               *slash = '\0';
                                bb_make_directory(new_filename, -1, FILEUTILS_RECUR);
-                               *line_ptr = '/';
+                               *slash = '/';
                        }
                        backup_filename = NULL;
                        saved_stat.st_mode = 0644;
@@ -134,10 +130,16 @@ int patch_main(int argc ATTRIBUTE_UNUSED, char **argv)
                dst_stream = xfopen(new_filename, "w");
                fchmod(fileno(dst_stream), saved_stat.st_mode);
                src_stream = NULL;
-
-               if (backup_filename && !stat(original_filename, &saved_stat)) {
-                       src_stream = xfopen((strcmp(original_filename, new_filename)) ?
-                                                           original_filename : backup_filename, "r");
+               if (backup_filename && stat(original_filename, &saved_stat) == 0) {
+                       // strcmp() is never 0! Otherwise:
+                       // original_filename == new_filename,
+                       // stat(original_filename) == stat(new_filename),
+                       // stat(new_filename) == 0,
+                       // but we renamed new_filename if it existed!
+                       // stat() must fail!
+                       //src_stream = xfopen((strcmp(original_filename, new_filename)) ?
+                       //                      original_filename : backup_filename, "r");
+                       src_stream = xfopen(original_filename, "r");
                }
 
                printf("patching file %s\n", new_filename);
@@ -147,16 +149,12 @@ int patch_main(int argc ATTRIBUTE_UNUSED, char **argv)
                while (patch_line) {
                        unsigned count;
                        unsigned src_beg_line;
-                       unsigned unused;
-                       unsigned hunk_offset_start = 0;
-                       smallint hunk_error = 0;
-
-                       /* This bit should be improved */
-                       if ((sscanf(patch_line, "@@ -%d,%d +%d,%d @@", &src_beg_line, &unused, &dest_beg_line, &unused) != 4)
-                        && (sscanf(patch_line, "@@ -%d,%d +%d @@", &src_beg_line, &unused, &dest_beg_line) != 3)
-                        && (sscanf(patch_line, "@@ -%d +%d,%d @@", &src_beg_line, &dest_beg_line, &unused) != 3)
-                       ) {
-                               /* No more hunks for this file */
+                       unsigned hunk_offset_start;
+                       unsigned src_last_line = 1;
+
+                       if ((sscanf(patch_line, "@@ -%d,%d +%d", &src_beg_line, &src_last_line, &dest_beg_line) != 3)
+                        && (sscanf(patch_line, "@@ -%d +%d", &src_beg_line, &dest_beg_line) != 2)
+                       ) { /* No more hunks for this file */
                                break;
                        }
                        hunk_count++;
@@ -172,14 +170,22 @@ int patch_main(int argc ATTRIBUTE_UNUSED, char **argv)
                                dest_cur_line += count;
                                copy_trailing_lines_flag = 1;
                        }
-                       hunk_offset_start = src_cur_line;
+                       src_last_line += hunk_offset_start = src_cur_line;
 
                        while (1) {
                                free(patch_line);
                                patch_line = xmalloc_fgets(patch_file);
-                               if (patch_line == NULL) break;
-                               if ((*patch_line == '-') || (*patch_line == ' ')) {
+                               if (patch_line == NULL)
+                                       break; /* EOF */
+                               if ((*patch_line != '-') && (*patch_line != '+')
+                                && (*patch_line != ' ')
+                               ) {
+                                       break; /* End of hunk */
+                               }
+                               if (*patch_line != '+') { /* '-', ' ' or '\n' */
                                        char *src_line = NULL;
+                                       if (src_cur_line == src_last_line)
+                                               break;
                                        if (src_stream) {
                                                src_line = xmalloc_fgets(src_stream);
                                                if (src_line) {
@@ -188,26 +194,19 @@ int patch_main(int argc ATTRIBUTE_UNUSED, char **argv)
                                                        free(src_line);
                                                        if (diff) src_line = NULL;
                                                }
-                                               if (!src_line) {
-                                                       bb_error_msg("hunk #%d FAILED at %d", hunk_count, hunk_offset_start);
-                                                       hunk_error = 1;
-                                                       break;
-                                               }
                                        }
-                                       if (*patch_line == ' ') {
-                                               fputs(patch_line + 1, dst_stream);
-                                               dest_cur_line++;
+                                       if (!src_line) {
+                                               bb_error_msg("hunk #%u FAILED at %u", hunk_count, hunk_offset_start);
+                                               bad_hunk_count++;
+                                               break;
+                                       }
+                                       if (*patch_line == '-') {
+                                               continue;
                                        }
-                               } else if (*patch_line == '+') {
-                                       fputs(patch_line + 1, dst_stream);
-                                       dest_cur_line++;
-                               } else {
-                                       break;
                                }
+                               fputs(patch_line + 1, dst_stream);
+                               dest_cur_line++;
                        } /* end of while loop handling one hunk */
-                       if (hunk_error) {
-                               bad_hunk_count++;
-                       }
                } /* end of while loop handling one file */
 
                /* Cleanup last patched file */
@@ -217,9 +216,7 @@ int patch_main(int argc ATTRIBUTE_UNUSED, char **argv)
                if (src_stream) {
                        fclose(src_stream);
                }
-               if (dst_stream) {
-                       fclose(dst_stream);
-               }
+               fclose(dst_stream);
                if (bad_hunk_count) {
                        ret = 1;
                        bb_error_msg("%u out of %u hunk FAILED", bad_hunk_count, hunk_count);
@@ -232,11 +229,12 @@ int patch_main(int argc ATTRIBUTE_UNUSED, char **argv)
                        if ((dest_cur_line == 0) || (dest_beg_line == 0)) {
                                /* The new patched file is empty, remove it */
                                xunlink(new_filename);
-                               if (strcmp(new_filename, original_filename) != 0)
-                                       xunlink(original_filename);
+                               /* original_filename and new_filename may be the same file */
+                               unlink(original_filename);
                        }
                }
        } /* end of "while there are patch lines" */
+quit:
 
        /* 0 = SUCCESS
         * 1 = Some hunks failed