view.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

#include "stdinc.h"
#include "dat.h"
#include "fns.h"
#include <draw.h>
#include <event.h>

/* --- tree.h */
typedef struct Tree Tree;
typedef struct Tnode Tnode;

struct Tree
{
	Tnode *root;
	Point offset;
	Image *clipr;
};

struct Tnode
{
	Point offset;

	char *str;
//	char *(*strfn)(Tnode*);
//	uint (*draw)(Tnode*, Image*, Image*, Point);
	void (*expand)(Tnode*);
	void (*collapse)(Tnode*);

	uint expanded;
	Tnode **kid;
	int nkid;
	void *aux;
};

typedef struct Atree Atree;
struct Atree
{
	int resizefd;
	Tnode *root;
};

Atree *atreeinit(char*);

/* --- visfossil.c */
Tnode *initxheader(void);
Tnode *initxcache(char *name);
Tnode *initxsuper(void);
Tnode *initxlocalroot(char *name, u32int addr);
Tnode *initxentry(Entry);
Tnode *initxsource(Entry, int);
Tnode *initxentryblock(Block*, Entry*);
Tnode *initxdatablock(Block*, uint);
Tnode *initxroot(char *name, uchar[VtScoreSize]);

int fd;
Header h;
Super super;
VtSession *z;
VtRoot vac;
int showinactive;

/*
 * dumbed down versions of fossil routines
 */
char*
bsStr(int state)
{
	static char s[100];

	if(state == BsFree)
		return "Free";
	if(state == BsBad)
		return "Bad";

	sprint(s, "%x", state);
	if(!(state&BsAlloc))
		strcat(s, ",Free");	/* should not happen */
	if(state&BsVenti)
		strcat(s, ",Venti");
	if(state&BsClosed)
		strcat(s, ",Closed");
	return s;
}

char *bttab[] = {
	"BtData",
	"BtData+1",
	"BtData+2",
	"BtData+3",
	"BtData+4",
	"BtData+5",
	"BtData+6",
	"BtData+7",
	"BtDir",
	"BtDir+1",
	"BtDir+2",
	"BtDir+3",
	"BtDir+4",
	"BtDir+5",
	"BtDir+6",
	"BtDir+7",
};

char*
btStr(int type)
{
	if(type < nelem(bttab))
		return bttab[type];
	return "unknown";
}
#pragma varargck argpos stringnode 1

Block*
allocBlock(void)
{
	Block *b;

	b = mallocz(sizeof(Block)+h.blockSize, 1);
	b->data = (void*)&b[1];
	return b;
}

void
blockPut(Block *b)
{
	free(b);
}

static u32int
partStart(int part)
{
	switch(part){
	default:
		assert(0);
	case PartSuper:
		return h.super;
	case PartLabel:
		return h.label;
	case PartData:
		return h.data;
	}
}


static u32int
partEnd(int part)
{
	switch(part){
	default:
		assert(0);
	case PartSuper:
		return h.super+1;
	case PartLabel:
		return h.data;
	case PartData:
		return h.end;
	}
}

Block*
readBlock(int part, u32int addr)
{
	u32int start, end;
	u64int offset;
	int n, nn;
	Block *b;
	uchar *buf;

	start = partStart(part);
	end = partEnd(part);
	if(addr >= end-start){
		werrstr("bad addr 0x%.8ux; wanted 0x%.8ux - 0x%.8ux", addr, start, end);
		return nil;
	}

	b = allocBlock();
	b->addr = addr;
	buf = b->data;
	offset = ((u64int)(addr+start))*h.blockSize;
	n = h.blockSize;
	while(n > 0){
		nn = pread(fd, buf, n, offset);
		if(nn < 0){
			blockPut(b);
			return nil;
		}
		if(nn == 0){
			werrstr("short read");
			blockPut(b);
			return nil;
		}
		n -= nn;
		offset += nn;
		buf += nn;
	}
	return b;
}

int vtType[BtMax] = {
	VtDataType,		/* BtData | 0  */
	VtPointerType0,		/* BtData | 1  */
	VtPointerType1,		/* BtData | 2  */
	VtPointerType2,		/* BtData | 3  */
	VtPointerType3,		/* BtData | 4  */
	VtPointerType4,		/* BtData | 5  */
	VtPointerType5,		/* BtData | 6  */
	VtPointerType6,		/* BtData | 7  */
	VtDirType,		/* BtDir | 0  */
	VtPointerType0,		/* BtDir | 1  */
	VtPointerType1,		/* BtDir | 2  */
	VtPointerType2,		/* BtDir | 3  */
	VtPointerType3,		/* BtDir | 4  */
	VtPointerType4,		/* BtDir | 5  */
	VtPointerType5,		/* BtDir | 6  */
	VtPointerType6,		/* BtDir | 7  */
};

Block*
ventiBlock(uchar score[VtScoreSize], uint type)
{
	int n;
	Block *b;

	b = allocBlock();
	memmove(b->score, score, VtScoreSize);
	b->addr = NilBlock;

	n = vtRead(z, b->score, vtType[type], b->data, h.blockSize);
	if(n < 0){
		fprint(2, "vtRead returns %d: %R\n", n);
		blockPut(b);
		return nil;
	}
	vtZeroExtend(vtType[type], b->data, n, h.blockSize);
	b->l.type = type;
	b->l.state = 0;
	b->l.tag = 0;
	b->l.epoch = 0;
	return b;
}

Block*
dataBlock(uchar score[VtScoreSize], uint type, uint tag)
{
	Block *b, *bl;
	int lpb;
	Label l;
	u32int addr;

	addr = globalToLocal(score);
	if(addr == NilBlock)
		return ventiBlock(score, type);

	lpb = h.blockSize/LabelSize;
	bl = readBlock(PartLabel, addr/lpb);
	if(bl == nil)
		return nil;
	if(!labelUnpack(&l, bl->data, addr%lpb)){
		werrstr("%R");
		blockPut(bl);
		return nil;
	}
	blockPut(bl);
	if(l.type != type){
		werrstr("type mismatch; got %d (%s) wanted %d (%s)",
			l.type, btStr(l.type), type, btStr(type));
		return nil;
	}
	if(tag && l.tag != tag){
		werrstr("tag mismatch; got 0x%.8ux wanted 0x%.8ux",
			l.tag, tag);
		return nil;
	}
	b = readBlock(PartData, addr);
	if(b == nil)
		return nil;
	b->l = l;
	return b;
}

Entry*
copyEntry(Entry e)
{
	Entry *p;

	p = mallocz(sizeof *p, 1);
	*p = e;
	return p;
}

MetaBlock*
copyMetaBlock(MetaBlock mb)
{
	MetaBlock *p;

	p = mallocz(sizeof mb, 1);
	*p = mb;
	return p;
}

/*
 * visualizer 
 */

Tnode*
stringnode(char *fmt, ...)
{
	va_list arg;
	Tnode *t;

	t = mallocz(sizeof(Tnode), 1);
	va_start(arg, fmt);
	t->str = vsmprint(fmt, arg);
	va_end(arg);
	t->nkid = -1;
	return t;
}

void
xcacheexpand(Tnode *t)
{
	if(t->nkid >= 0)
		return;

	t->nkid = 1;
	t->kid = mallocz(sizeof(t->kid[0])*t->nkid, 1);
	t->kid[0] = initxheader();
}

Tnode*
initxcache(char *name)
{
	Tnode *t;

	if((fd = open(name, OREAD)) < 0)
		sysfatal("cannot open %s: %r", name);

	t = stringnode("%s", name);
	t->expand = xcacheexpand;
	return t;
}

void
xheaderexpand(Tnode *t)
{
	if(t->nkid >= 0)
		return;

	t->nkid = 1;
	t->kid = mallocz(sizeof(t->kid[0])*t->nkid, 1);
	t->kid[0] = initxsuper();
	//t->kid[1] = initxlabel(h.label);
	//t->kid[2] = initxdata(h.data);
}

Tnode*
initxheader(void)
{
	u8int buf[HeaderSize];
	Tnode *t;

	if(pread(fd, buf, HeaderSize, HeaderOffset) < HeaderSize)
		return stringnode("error reading header: %r");
	if(!headerUnpack(&h, buf))
		return stringnode("error unpacking header: %R");

	t = stringnode("header "
		"version=%#ux (%d) "
		"blockSize=%#ux (%d) "
		"super=%#lux (%ld) "
		"label=%#lux (%ld) "
		"data=%#lux (%ld) "
		"end=%#lux (%ld)",
		h.version, h.version, h.blockSize, h.blockSize,
		h.super, h.super,
		h.label, h.label, h.data, h.data, h.end, h.end);
	t->expand = xheaderexpand;
	return t;
}

void
xsuperexpand(Tnode *t)
{
	if(t->nkid >= 0)
		return;

	t->nkid = 1;
	t->kid = mallocz(sizeof(t->kid[0])*t->nkid, 1);
	t->kid[0] = initxlocalroot("active", super.active);
//	t->kid[1] = initxlocalroot("next", super.next);
//	t->kid[2] = initxlocalroot("current", super.current);
}

Tnode*
initxsuper(void)
{
	Block *b;
	Tnode *t;

	b = readBlock(PartSuper, 0);
	if(b == nil)
		return stringnode("reading super: %r");
	if(!superUnpack(&super, b->data)){
		blockPut(b);
		return stringnode("unpacking super: %R");
	}
	blockPut(b);
	t = stringnode("super "
		"version=%#ux "
		"epoch=[%#ux,%#ux) "
		"qid=%#llux "
		"active=%#x "
		"next=%#x "
		"current=%#x "
		"last=%V "
		"name=%s",
		super.version, super.epochLow, super.epochHigh,
		super.qid, super.active, super.next, super.current,
		super.last, super.name);
	t->expand = xsuperexpand;
	return t;
}

void
xvacrootexpand(Tnode *t)
{
	if(t->nkid >= 0)
		return;

	t->nkid = 1;
	t->kid = mallocz(sizeof(t->kid[0])*t->nkid, 1);
	t->kid[0] = initxroot("root", vac.score);
}

Tnode*
initxvacroot(uchar score[VtScoreSize])
{
	Tnode *t;
	uchar buf[VtRootSize];
	int n;

	if((n = vtRead(z, score, VtRootType, buf, VtRootSize)) < 0)
		return stringnode("reading root %V: %R", score);

	if(!vtRootUnpack(&vac, buf))
		return stringnode("unpack %d-byte root: %R", n);

	h.blockSize = vac.blockSize;
	t = stringnode("vac version=%#ux name=%s type=%s blockSize=%ud score=%V prev=%V",
		vac.version, vac.name, vac.type, vac.blockSize, vac.score, vac.prev);
	t->expand = xvacrootexpand;
	return t;
}

Tnode*
initxlabel(Label l)
{
	return stringnode("label type=%s state=%s epoch=%#ux tag=%#ux",
		btStr(l.type), bsStr(l.state), l.epoch, l.tag);
}

typedef struct Xblock Xblock;
struct Xblock
{
	Tnode;
	Block *b;
	int (*gen)(void*, Block*, int, Tnode**);
	void *arg;
	int printlabel;
};

void
xblockexpand(Tnode *tt)
{
	int i, j;
	enum { Q = 32 };
	Xblock *t = (Xblock*)tt;
	Tnode *nn;

	if(t->nkid >= 0)
		return;

	j = 0;
	if(t->printlabel){
		t->kid = mallocz(Q*sizeof(t->kid[0]), 1);
		t->kid[0] = initxlabel(t->b->l);
		j = 1;
	}

	for(i=0;; i++){
		switch((*t->gen)(t->arg, t->b, i, &nn)){
		case -1:
			t->nkid = j;
			return;
		case 0:
			break;
		case 1:
			if(j%Q == 0)
				t->kid = realloc(t->kid, (j+Q)*sizeof(t->kid[0]));
			t->kid[j++] = nn;
			break;
		}
	}
}

int
nilgen(void*, Block*, int, Tnode**)
{
	return -1;
}

Tnode*
initxblock(Block *b, char *s, int (*gen)(void*, Block*, int, Tnode**), void *arg)
{
	Xblock *t;

	if(gen == nil)
		gen = nilgen;
	t = mallocz(sizeof(Xblock), 1);
	t->b = b;
	t->gen = gen;
	t->arg = arg;
	if(b->addr == NilBlock)
		t->str = smprint("Block %V: %s", b->score, s);
	else
		t->str = smprint("Block %#ux: %s", b->addr, s);
	t->printlabel = 1;
	t->nkid = -1;
	t->expand = xblockexpand;
	return t;
}

int
xentrygen(void *v, Block *b, int o, Tnode **tp)
{
	Entry e;
	Entry *ed;

	ed = v;
	if(o >= ed->dsize/VtEntrySize)
		return -1;

	entryUnpack(&e, b->data, o);
	if(!showinactive && !(e.flags & VtEntryActive))
		return 0;
	*tp = initxentry(e);
	return 1;
}

Tnode*
initxentryblock(Block *b, Entry *ed)
{
	return initxblock(b, "entry", xentrygen, ed);
}

typedef struct Xentry Xentry;
struct Xentry 
{
	Tnode;
	Entry e;
};

void
xentryexpand(Tnode *tt)