--- toys/pending/git.c | 64 +++++++++++++++++++++++++--------------------- 1 file changed, 35 insertions(+), 29 deletions(-)
diff --git a/toys/pending/git.c b/toys/pending/git.c index 0e79ac60..36d046d7 100644 --- a/toys/pending/git.c +++ b/toys/pending/git.c @@ -70,20 +70,21 @@ config GITCHECKOUT #include "zlib.h" //ToDo: borrowed from libz to not refactor deflate.c GLOBALS( - char *url, *name; - struct IndexV2 *i; + char *url, *name; //git repo remote url and init directory name + struct IndexV2 *i; //git creates a index for each pack file, git clone just needs one index for the received pack file ) -//git index format v2 https://github.com/git/git/blob/master/Documentation/gitformat-pack.txt#L266 +//git index format v2 described at https://github.com/git/git/blob/master/Documentation/gitformat-pack.txt#L266 struct IndexV2 { - char header[8]; - unsigned fot[256]; - char (*sha1)[20]; - unsigned *crc, *offset; - long long *offset64; //not supported yet - char packsha1[20], idxsha1[20]; + char header[8];// Git 4 byte magic number and 4 byte version number + unsigned fot[256];//A fan-out table + char (*sha1)[20];//Table of sorted object names(SHA1 hashes) + unsigned *crc, *offset;//Table of 4-bit CRC32 values and object offsets in pack file + long long *offset64; //8 byte offests -- not supported yet + char packsha1[20], idxsha1[20];//SHA1 hash of pack file and SHA1 hash of index file }; +//TODO:This function is not used before git clone persists an index V2 static void read_index(struct IndexV2 *i) { FILE *fpi; @@ -116,21 +117,20 @@ static void read_index(struct IndexV2 *i) } } -static char *l; //for saving the insertion position +//static char *l; //for saving the insertion position -int cmp (const void *i, void *j) -{ - l = j; //inject inseration position in compare to binary search - return strncmp(i, j, 20); -} +//int cmp (const void *i, void *j) +//{ +// l = j; //inject inseration position in compare to binary search +// return strncmp(i, j, 20); +//} -//inspired by musl bsearch +//inspired by musl bsearch http://git.musl-libc.org/cgit/musl/tree/src/stdlib/bsearch.c long bsearchpos(const void *k, const void *a, size_t h, size_t w) { long l = 0, m = 0, r = 0; if (!h) return 0; - //printf("Array: %p Key:%p\n", a, k); while (h>0) { m = l+(h/2); r = strncmp(k, a+(m*w), 20); @@ -142,6 +142,7 @@ long bsearchpos(const void *k, const void *a, size_t h, size_t w) return m += (r>0) ? 1 : 0; } +//find offset position in packfile for given SHA1 hash long get_index(struct IndexV2 *i, char *h) { long pos = bsearchpos(h, i->sha1[0], i->fot[255], 20); @@ -150,8 +151,7 @@ long get_index(struct IndexV2 *i, char *h) //https://github.com/git/git/blob/master/Documentation/gitformat-pack.txt#L35 //https://yqintl.alicdn.com/eef7fe4f22cc97912cee011c99d3fe5821ae9e88.png - -//read type and lenght of an packed object +//read type and length of an packed object at a given offset unsigned long long unpack(FILE *fpp, int *type, long *offset) { int bitshift= 4; @@ -248,6 +248,7 @@ int inf(FILE *source, char *dest) //modified signature to ease use } //https://github.com/git/git/blob/master/Documentation/gitformat-pack.txt#L72 +//Set object to the index after adding prefix, calculating the hash and finding the position long set_object(struct IndexV2 *idx, int type, char *o, unsigned count, unsigned ofs) { @@ -258,7 +259,7 @@ long set_object(struct IndexV2 *idx, int type, char *o, unsigned count, long pos = 0; printf("Alloc... "); - if (h == NULL) error_exit("Hash malloc failed in set_object"); + //append a object prefix based on its type (not included in packfile) switch(type) { case 1: p = xmprintf("commit %d", count); break; //count is used as o can contain \0 in the string case 2: p = xmprintf("tree %d", count); break; @@ -284,7 +285,7 @@ long set_object(struct IndexV2 *idx, int type, char *o, unsigned count, printf("Resize sha1 array..idx->fot[255]%d\n", idx->fot[255]); //Memory management for insert //TODO:Could be also a single malloc at gitfetch based on the nbr of objects in pack - //Did not fix the TODO yet, because set_object could be reused for other command im mem mgmt is here + //Did not fix the TODO yet, because set_object could be reused for other commands adding single objects to the index idx->sha1 = realloc(idx->sha1, (idx->fot[255]+1)*20*sizeof(char)); printf("Mem copy sha1 array..sizeof(idx->sha1)%ld\n", sizeof(idx->sha1)); memmove(&idx->sha1[pos+1], &idx->sha1[pos], (idx->fot[255]-pos)*20*sizeof(char)); @@ -303,11 +304,12 @@ long set_object(struct IndexV2 *idx, int type, char *o, unsigned count, return ofs; } +//init a git repository in a given directory name static void gitinit(char *name) { - //For git clone actually only refs and object/pack needed + //For git clone actually only refs and object/pack are needed if (mkdir(name, 0755)!=0){ - //I create the other for a git compliant folder structure + //I create the others for a git compliant folder structure mkdir(xmprintf("%s%s", name, "/.git"), 0755); mkdir(xmprintf("%s%s", name, "/.git/objects"), 0755); mkdir(xmprintf("%s%s", name, "/.git/objects/pack"), 0755); @@ -325,6 +327,7 @@ static void gitinit(char *name) } } +//set basic configuration and add remote URL static void gitremote(char *url) { if (access(".git/config", F_OK)!=0) { @@ -346,6 +349,7 @@ static void gitremote(char *url) // this is most likely still buggy and create a late observable heap overflow larger deltafied repos // https://stackoverflow.com/a/14303988 +// resolve deltafied objects in the pack file, see URL in comments for further explainations char *resolve_delta(char *s, char *d, long dsize, unsigned *count) { long pos = 0, bitshift = 0; @@ -395,18 +399,14 @@ char *resolve_delta(char *s, char *d, long dsize, unsigned *count) printf("Pos\n"); } else { //https://github.com/git/git/blob/master/Documentation/gitformat-pack.txt#L153 -// printf("Case 0\n"); + printf("Case 0\n"); size = d[pos++]; //incrememt -// printf("Memcopy %d\n", size); memcpy(t+*count, d+pos, size); -// printf("Pos %ld\n", pos); pos += size; } *count += size; printf("Target: \n"); -// for (int k = 0; k<*count; k++) { printf("%c", t[k]); } -// printf("\n"); } free(s); free(d); @@ -414,6 +414,7 @@ char *resolve_delta(char *s, char *d, long dsize, unsigned *count) return t; } +//unpack object (,resolve deltafied objects recursively) and return the unpacked object char *unpack_object(FILE *fpp, struct IndexV2 *i, long offset, unsigned *count, int *type) { @@ -523,6 +524,8 @@ void write_children(char *hash, char *path, FILE *fpp) { printf("Child: %s done\n", path); } +//fetches the meta data from the remote repository,requests a pack file for the remote master head, +//unpacks all objects and set objects to the index static void gitfetch(void) { printf("refs\n"); @@ -549,6 +552,7 @@ static void gitfetch(void) strcpy(h,&h[4]); h[40]='\0'; printf("Master HEAD hash: %s\n",h); + //TODO: Persist hash to /refs/master/HEAD printf("pack\n"); if ((pid = fork())==0) execv("toybox", (char *[]){"toybox", "wget", "-O", ".git/objects/pack/temp.pack", "-p", xmprintf("$'0032want %s\n00000009done\n'", h), "https://github.com/landley/toybox/git-upload-pack";, (char*)0}); //TODO: does not skip 0008NAK printf("init\n"); perror("execv\n"); @@ -587,6 +591,8 @@ static void gitfetch(void) fclose(fpp); } +//Checkout HEAD to the working directory by recursing write_children +//TODO: Replase static hashes with hash read from refs/<branch>/head static void gitcheckout(char *name) { @@ -655,7 +661,7 @@ void gitcheckout_main(void) gitcheckout(xstrdup(toys.optargs[0])); } - +// Command to wget refs and pack file using toybox wget to place them manually into the repository // ./toybox wget -O - -d https://github.com/landley/toybox/info/refs?service=git-upload-pack | less // ./toybox wget -O pack.dat -d -p $'0032want 8cf1722f0fde510ea81d13b31bde1e48917a0306\n00000009done\n' https://github.com/landley/toybox/git-upload-pack -- 2.20.1 _______________________________________________ Toybox mailing list [email protected] http://lists.landley.net/listinfo.cgi/toybox-landley.net
